Support tests in freestanding

Summary:
Freestanding is *weird*. The standard allows it to differ in a bunch of odd
manners from regular C++, and the committee would like to improve that
situation. I'd like to make libc++ behave better with what freestanding should
be, so that it can be a tool we use in improving the standard. To do that we
need to try stuff out, both with "freestanding the language mode" and
"freestanding the library subset".

Let's start with the super basic: run the libc++ tests in freestanding, using
clang as the compiler, and see what works. The easiest hack to do this:

In utils/libcxx/test/config.py add:

  self.cxx.compile_flags += ['-ffreestanding']

Run the tests and they all fail.

Why? Because in freestanding `main` isn't special. This "not special" property
has two effects: main doesn't get mangled, and main isn't allowed to omit its
`return` statement. The first means main gets mangled and the linker can't
create a valid executable for us to test. The second means we spew out warnings
(ew) and the compiler doesn't insert the `return` we omitted, and main just
falls of the end and does whatever undefined behavior (if you're luck, ud2
leading to non-zero return code).

Let's start my work with the basics. This patch changes all libc++ tests to
declare `main` as `int main(int, char**` so it mangles consistently (enabling us
to declare another `extern "C"` main for freestanding which calls the mangled
one), and adds `return 0;` to all places where it was missing. This touches 6124
files, and I apologize.

The former was done with The Magic Of Sed.

The later was done with a (not quite correct but decent) clang tool:

  https://gist.github.com/jfbastien/793819ff360baa845483dde81170feed

This works for most tests, though I did have to adjust a few places when e.g.
the test runs with `-x c`, macros are used for main (such as for the filesystem
tests), etc.

Once this is in we can create a freestanding bot which will prevent further
regressions. After that, we can start the real work of supporting C++
freestanding fairly well in libc++.

<rdar://problem/47754795>

Reviewers: ldionne, mclow.lists, EricWF

Subscribers: christof, jkorous, dexonsmith, arphaman, miyuki, libcxx-commits

Differential Revision: https://reviews.llvm.org/D57624

llvm-svn: 353086

5748 files changed, 17112 insertions, 5823 deletions

diff --git a/libcxx/test/std/algorithms/alg.c.library/tested_elsewhere.pass.cpp b/libcxx/test/std/algorithms/alg.c.library/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.c.library/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.c.library/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy.pass.cpp
index c18550a160a..9dcace7a03d 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy.pass.cpp
@@ -46,7 +46,7 @@ test()
         assert(ia[i] == ib[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<int*> >();
@@ -86,4 +86,6 @@ int main()
 // #if TEST_STD_VER > 17
 //     static_assert(test_constexpr());
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_backward.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_backward.pass.cpp
index bed5ff63629..3b20fbde5ba 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_backward.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_backward.pass.cpp
@@ -49,7 +49,7 @@ test()
         assert(ia[i] == ib[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
     test<bidirectional_iterator<const int*>, random_access_iterator<int*> >();
@@ -66,4 +66,6 @@ int main()
 // #if TEST_STD_VER > 17
 //     static_assert(test_constexpr());
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp
index 3d29d62971c..903bcbe6c25 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp
@@ -53,7 +53,7 @@ test()
         assert(ib[i] % 3 == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<int*> >();
@@ -93,4 +93,6 @@ int main()
 // #if TEST_STD_VER > 17
 //     static_assert(test_constexpr());
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp
index 540211752f3..2e181cfd49c 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp
@@ -49,7 +49,7 @@ test()
         assert(ia[i] == ib[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<int*> >();
@@ -89,4 +89,6 @@ int main()
 // #if TEST_STD_VER > 17
 //     static_assert(test_constexpr());
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill.pass.cpp
index bc6a2c80e6f..da56ec30f12 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill.pass.cpp
@@ -56,7 +56,7 @@ test_int()
     assert(ia[3] == 1);
 }
 
-int main()
+int main(int, char**)
 {
     test_char<forward_iterator<char*> >();
     test_char<bidirectional_iterator<char*> >();
@@ -71,4 +71,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
index a133ba63b5b..e774c915fa6 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
@@ -148,7 +148,7 @@ void test6()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_char<forward_iterator<char*> >();
     test_char<bidirectional_iterator<char*> >();
@@ -170,4 +170,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate.pass.cpp
index 4830ea5018b..29d32d71567 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate.pass.cpp
@@ -51,7 +51,7 @@ test()
     assert(ia[3] == 1);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -61,4 +61,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
index 5b6712d44ad..4ffdc648f62 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
@@ -74,7 +74,7 @@ test()
     test2<Iter, long double>();
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -84,4 +84,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move.pass.cpp
index cab5e5a4e7c..cdb126d4942 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move.pass.cpp
@@ -54,7 +54,7 @@ test1()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<int*> >();
@@ -127,4 +127,6 @@ int main()
     test1<std::unique_ptr<int>*, random_access_iterator<std::unique_ptr<int>*> >();
     test1<std::unique_ptr<int>*, std::unique_ptr<int>*>();
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp
index f9a6e77c815..365c1a1158d 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp
@@ -54,7 +54,7 @@ test1()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
     test<bidirectional_iterator<const int*>, random_access_iterator<int*> >();
@@ -81,4 +81,6 @@ int main()
     test1<std::unique_ptr<int>*, random_access_iterator<std::unique_ptr<int>*> >();
     test1<std::unique_ptr<int>*, std::unique_ptr<int>*>();
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp
index 460cc5e0588..6c741490f1f 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp
@@ -35,7 +35,7 @@ TEST_CONSTEXPR bool test_constexpr() {
 #endif
 
 
-int main() {
+int main(int, char**) {
   {
     const int ia[] = {1, 2, 3, 4, 5, 6};
     unary_counting_predicate<is_odd, int> pred((is_odd()));
@@ -94,4 +94,6 @@ int main() {
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp
index c3749868b97..97af585b932 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp
@@ -93,9 +93,11 @@ test()
         assert(!is_odd()(*i));
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp
index fcfcc7c7964..26713634654 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp
@@ -43,7 +43,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         const int ia[] = {1, 2, 3, 4, 6, 8, 5, 7};
@@ -68,4 +68,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_point.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_point.pass.cpp
index e6dd5c0414a..5da1b815043 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_point.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_point.pass.cpp
@@ -35,7 +35,7 @@ TEST_CONSTEXPR bool test_constexpr() {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
         const int ia[] = {2, 4, 6, 8, 10};
@@ -89,4 +89,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/stable_partition.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/stable_partition.pass.cpp
index 7e886576f76..0358f7030e8 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/stable_partition.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.partitions/stable_partition.pass.cpp
@@ -301,7 +301,7 @@ test1()
 
 #endif  // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<std::pair<int,int>*> >();
     test<random_access_iterator<std::pair<int,int>*> >();
@@ -310,4 +310,6 @@ int main()
 #if TEST_STD_VER >= 11
     test1<bidirectional_iterator<std::unique_ptr<int>*> >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp
index a9aa64e4812..c01104c0cfb 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp
@@ -32,9 +32,11 @@ template <class PopulationIterator, class SampleIterator> void test() {
                             SampleIterator(oa), os, g);
 }
 
-int main() {
+int main(int, char**) {
   // expected-error-re@algorithm:* {{static_assert failed{{( due to requirement '.*')?}} "SampleIterator must meet the requirements of RandomAccessIterator"}}
   // expected-error@algorithm:* 2 {{does not provide a subscript operator}}
   // expected-error@algorithm:* {{invalid operands}}
   test<input_iterator<int *>, output_iterator<int *> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
index bfc71e779fa..40f2037f00e 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
@@ -136,7 +136,7 @@ void test_small_population() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test<input_iterator, int, random_access_iterator, int>();
   test<forward_iterator, int, output_iterator, int>();
   test<forward_iterator, int, random_access_iterator, int>();
@@ -156,4 +156,6 @@ int main() {
   test_small_population<input_iterator, int, random_access_iterator, int>();
   test_small_population<forward_iterator, int, output_iterator, int>();
   test_small_population<forward_iterator, int, random_access_iterator, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp
index aa7c74788d7..58e6084626a 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp
@@ -48,7 +48,9 @@ void test_stability(bool expect_stable) {
   assert(expect_stable == !unstable);
 }
 
-int main() {
+int main(int, char**) {
   test_stability<forward_iterator<int *>, output_iterator<int *> >(true);
   test_stability<input_iterator<int *>, random_access_iterator<int *> >(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.pass.cpp
index 6ae7eb964a1..cb83cde936e 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.pass.cpp
@@ -39,7 +39,7 @@ test_with_iterator()
 }
 
 
-int main()
+int main(int, char**)
 {
     int ia[]  = {1, 2, 3, 4};
     int ia1[] = {1, 4, 3, 2};
@@ -57,4 +57,5 @@ int main()
     test_with_iterator<random_access_iterator<int*> >();
     test_with_iterator<int*>();
 
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_rand.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_rand.pass.cpp
index ffdb098fc53..dd5398dace1 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_rand.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_rand.pass.cpp
@@ -51,8 +51,9 @@ test_with_iterator()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_with_iterator<random_access_iterator<int*> >();
     test_with_iterator<int*>();
-}
\ No newline at end of file
+    return 0;
+}
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp
index 865eb488751..d5f162bced4 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
     int ia1[] = {2, 7, 1, 4, 3, 6, 5, 10, 9, 8};
@@ -31,4 +31,6 @@ int main()
     std::shuffle(ia, ia+sa, std::move(g));
     LIBCPP_ASSERT(std::equal(ia, ia+sa, ia2));
     assert(std::is_permutation(ia, ia+sa, ia2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove.pass.cpp
index 3c7651189e8..ebacec5f493 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove.pass.cpp
@@ -73,7 +73,7 @@ test1()
 }
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -90,4 +90,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy.pass.cpp
index ab8d6d8866f..8dedddb4c20 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy.pass.cpp
@@ -50,7 +50,7 @@ test()
     assert(ib[5] == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -85,4 +85,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy_if.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy_if.pass.cpp
index c4ad12fa8ca..7d10c6bd759 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_copy_if.pass.cpp
@@ -55,7 +55,7 @@ test()
     assert(ib[5] == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -90,4 +90,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_if.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_if.pass.cpp
index 35771b5a022..637a91707d3 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.remove/remove_if.pass.cpp
@@ -88,7 +88,7 @@ test1()
 }
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -105,4 +105,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace.pass.cpp
index 2f9dc692a89..1e91fc968cb 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace.pass.cpp
@@ -47,7 +47,7 @@ test()
     assert(ia[4] == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -57,4 +57,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy.pass.cpp
index a7e38b92bbe..da3fabf406b 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy.pass.cpp
@@ -54,7 +54,7 @@ test()
     assert(ib[4] == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -89,4 +89,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy_if.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy_if.pass.cpp
index 3daf1109ffc..26cbd705f49 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_copy_if.pass.cpp
@@ -58,7 +58,7 @@ test()
     assert(ib[4] == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -93,4 +93,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_if.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_if.pass.cpp
index d35927a1a9b..4f32b6e94a4 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/replace_if.pass.cpp
@@ -50,7 +50,7 @@ test()
     assert(ia[4] == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -60,4 +60,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp
index d39da540582..7838a0ca2f1 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp
@@ -51,9 +51,11 @@ test()
     assert(id[3] == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp
index 4758c4f1ebb..6967c446b75 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp
@@ -72,7 +72,7 @@ test()
     assert(jd[3] == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<const int*>, output_iterator<int*> >();
     test<bidirectional_iterator<const int*>, forward_iterator<int*> >();
@@ -95,4 +95,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
index a588b971c81..007faf685bf 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
@@ -419,7 +419,7 @@ test1()
 
 #endif  // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -434,4 +434,6 @@ int main()
     test1<std::unique_ptr<int>*>();
 
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate_copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate_copy.pass.cpp
index 5f71e094015..d66bf8caad6 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate_copy.pass.cpp
@@ -128,7 +128,7 @@ test()
     assert(ib[3] == 3);
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<const int*>, output_iterator<int*> >();
     test<bidirectional_iterator<const int*>, forward_iterator<int*> >();
@@ -151,4 +151,6 @@ int main()
 // #if TEST_STD_VER > 17
 //    static_assert(test_constexpr());
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/iter_swap.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/iter_swap.pass.cpp
index 182b17914c8..419bb4bbbff 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/iter_swap.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/iter_swap.pass.cpp
@@ -16,11 +16,13 @@
 #include <algorithm>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int i = 1;
     int j = 2;
     std::iter_swap(&i, &j);
     assert(i == 2);
     assert(j == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
index 43cd4ce63f3..a47bbd24d95 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
@@ -105,7 +105,7 @@ void test2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*>, forward_iterator<int*> >();
     test<forward_iterator<int*>, bidirectional_iterator<int*> >();
@@ -150,4 +150,6 @@ int main()
 #endif // TEST_STD_VER >= 11
 
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/binary_transform.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/binary_transform.pass.cpp
index dc8101a25e0..ca7287bf24b 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/binary_transform.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/binary_transform.pass.cpp
@@ -56,7 +56,7 @@ test()
     assert(ib[4] == 1);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, input_iterator<int*> >();
@@ -236,4 +236,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/unary_transform.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/unary_transform.pass.cpp
index 9fc25adc330..85c3868207b 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/unary_transform.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/unary_transform.pass.cpp
@@ -57,7 +57,7 @@ test()
     assert(ib[4] == 5);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<int*> >();
@@ -97,4 +97,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique.pass.cpp
index 680633745df..7046d6a2bd4 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique.pass.cpp
@@ -181,7 +181,7 @@ test1()
 }
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -198,4 +198,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy.pass.cpp
index 3c34a9a3160..ba533507cd9 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy.pass.cpp
@@ -105,7 +105,7 @@ test()
     assert(ji[2] == 2);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -140,4 +140,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy_pred.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy_pred.pass.cpp
index b91c05e7652..e8ebeaead8c 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_copy_pred.pass.cpp
@@ -133,7 +133,7 @@ test()
     assert(count_equal::count == si-1);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -168,4 +168,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_pred.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_pred.pass.cpp
index d48bb6a6743..9f0c695e212 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.unique/unique_pred.pass.cpp
@@ -223,7 +223,7 @@ test1()
 }
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
@@ -240,4 +240,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find.pass.cpp
index de03da4ba1d..6d57c5869ab 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find.pass.cpp
@@ -30,7 +30,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -47,4 +47,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find_pred.pass.cpp
index a542cb81f17..c80bc9fff83 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.adjacent.find/adjacent_find_pred.pass.cpp
@@ -34,7 +34,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -54,4 +54,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.all_of/all_of.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.all_of/all_of.pass.cpp
index 61f6c2ceede..5c49878f6a4 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.all_of/all_of.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.all_of/all_of.pass.cpp
@@ -36,7 +36,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         int ia[] = {2, 4, 6, 8};
@@ -58,4 +58,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.any_of/any_of.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.any_of/any_of.pass.cpp
index ea9f8a4c8d1..22ae581d64b 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.any_of/any_of.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.any_of/any_of.pass.cpp
@@ -36,7 +36,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         int ia[] = {2, 4, 6, 8};
@@ -66,4 +66,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp
index f2e93719e5a..d864080df8d 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp
@@ -29,7 +29,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -43,4 +43,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count_if.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count_if.pass.cpp
index 7f6be6a278f..978f5fcdbe5 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count_if.pass.cpp
@@ -36,7 +36,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -53,4 +53,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp
index 81d46ce62f1..afd57491a40 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp
@@ -44,7 +44,7 @@ TEST_CONSTEXPR bool test_constexpr() {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 4, 5};
     const unsigned s = sizeof(ia)/sizeof(ia[0]);
@@ -88,4 +88,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal_pred.pass.cpp
index 03de33a6b3f..2b9619b73ee 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal_pred.pass.cpp
@@ -58,7 +58,7 @@ bool counting_equals ( const T &a, const T &b ) {
     return a == b;
 }
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 4, 5};
     const unsigned s = sizeof(ia)/sizeof(ia[0]);
@@ -114,4 +114,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end.pass.cpp
index 36633ee12f4..3060528a8e8 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end.pass.cpp
@@ -62,7 +62,7 @@ test()
     assert(std::find_end(Iter1(ia), Iter1(ia), Iter2(b), Iter2(b+1)) == Iter1(ia));
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
@@ -77,4 +77,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end_pred.pass.cpp
index 2b3ca1b0404..7358cf5f701 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/find_end_pred.pass.cpp
@@ -92,7 +92,7 @@ test()
     assert(count_equal::count <= 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
@@ -107,4 +107,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of.pass.cpp
index 1df8c1b8270..04468f74103 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of.pass.cpp
@@ -38,7 +38,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -69,4 +69,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of_pred.pass.cpp
index cb64ee80acb..3c32aee0e24 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.first.of/find_first_of_pred.pass.cpp
@@ -40,7 +40,7 @@ constexpr bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -75,4 +75,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp
index de7a4181c2d..9dc265f1854 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp
@@ -29,7 +29,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 4, 5};
     const unsigned s = sizeof(ia)/sizeof(ia[0]);
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if.pass.cpp
index 7b0ae435a88..6151a55b8f6 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if.pass.cpp
@@ -37,7 +37,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 4, 5};
     const unsigned s = sizeof(ia)/sizeof(ia[0]);
@@ -53,4 +53,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if_not.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if_not.pass.cpp
index 90e952171d4..36a75426999 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if_not.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find_if_not.pass.cpp
@@ -37,7 +37,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 4, 5};
     const unsigned s = sizeof(ia)/sizeof(ia[0]);
@@ -53,4 +53,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/for_each_n.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/for_each_n.pass.cpp
index b43acc13a57..f4dcd2d577a 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/for_each_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/for_each_n.pass.cpp
@@ -40,7 +40,7 @@ struct for_each_test
     void operator()(int& i) {++i; ++count;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef input_iterator<int*> Iter;
     int ia[] = {0, 1, 2, 3, 4, 5};
@@ -76,4 +76,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/test.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/test.pass.cpp
index 66336b2f9fa..4d129e75578 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/test.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/test.pass.cpp
@@ -37,7 +37,7 @@ struct for_each_test
     void operator()(int& i) {++i; ++count;}
 };
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 3, 4, 5};
     const unsigned s = sizeof(ia)/sizeof(ia[0]);
@@ -51,4 +51,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation.pass.cpp
index 3173276d190..2a2c796caac 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation.pass.cpp
@@ -35,7 +35,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         const int ia[] = {0};
@@ -618,4 +618,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation_pred.pass.cpp
index 914eccdcd02..ea4270ec409 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.is_permutation/is_permutation_pred.pass.cpp
@@ -55,7 +55,7 @@ struct eq {
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         const int ia[] = {0};
@@ -769,4 +769,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.none_of/none_of.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.none_of/none_of.pass.cpp
index c77ffb220b5..f3a4fea9022 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.none_of/none_of.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.none_of/none_of.pass.cpp
@@ -36,7 +36,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         int ia[] = {2, 4, 6, 8};
@@ -66,4 +66,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp
index a3fedafdc85..5aaa832ded0 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search.pass.cpp
@@ -95,7 +95,7 @@ test()
     assert(std::search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk)) == Iter1(ij+6));
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
@@ -121,4 +121,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp
index 50d710e6735..3c86127f38b 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp
@@ -79,7 +79,7 @@ test()
     (void)std::search_n(Iter(ic), Iter(ic+sc), UserDefinedIntegral<unsigned>(0), 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -88,4 +88,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp
index befa432bf28..13568939099 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp
@@ -158,7 +158,7 @@ test()
     count_equal::count = 0;
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -167,4 +167,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_pred.pass.cpp
index e61f7f9f0f6..f835d2f0945 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_pred.pass.cpp
@@ -110,7 +110,7 @@ test()
     assert(count_equal::count <= sh*3);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
@@ -125,4 +125,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp
index 74502d63156..72281b47fd7 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp
@@ -58,7 +58,7 @@ TEST_CONSTEXPR bool test_constexpr() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -89,4 +89,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch_pred.pass.cpp
index 2b21daab0b8..15edec03a25 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch_pred.pass.cpp
@@ -68,7 +68,7 @@ TEST_CONSTEXPR bool test_constexpr() {
 #define HAS_FOUR_ITERATOR_VERSION
 #endif
 
-int main()
+int main(int, char**)
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
     const unsigned sa = sizeof(ia)/sizeof(ia[0]);
@@ -114,4 +114,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search.pass.cpp
index 45c50ed0139..3d04d516140 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search.pass.cpp
@@ -61,7 +61,7 @@ test()
     test(Iter(v.data()), Iter(v.data()+v.size()), M, false);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {0, 2, 4, 6};
     for (int* e = d; e <= d+4; ++e)
@@ -76,4 +76,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search_comp.pass.cpp
index 75d7a64a311..a447853d2da 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/binary.search/binary_search_comp.pass.cpp
@@ -62,7 +62,7 @@ test()
     test(Iter(v.data()), Iter(v.data()+v.size()), M, false);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {6, 4, 2, 0};
     for (int* e = d; e <= d+4; ++e)
@@ -77,4 +77,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range.pass.cpp
index e8b15983296..e22bd5ad245 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range.pass.cpp
@@ -69,7 +69,7 @@ test()
         test(Iter(v.data()), Iter(v.data()+v.size()), x);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {0, 1, 2, 3};
     for (int* e = d; e <= d+4; ++e)
@@ -84,4 +84,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range_comp.pass.cpp
index b7b43a829d1..ab36e70331a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/equal.range/equal_range_comp.pass.cpp
@@ -68,7 +68,7 @@ test()
         test(Iter(v.data()), Iter(v.data()+v.size()), x);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {3, 2, 1, 0};
     for (int* e = d; e <= d+4; ++e)
@@ -83,4 +83,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound.pass.cpp
index 8f99ed99e1d..ce9b71c0624 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound.pass.cpp
@@ -64,7 +64,7 @@ test()
         test(Iter(v.data()), Iter(v.data()+v.size()), x);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {0, 1, 2, 3};
     for (int* e = d; e <= d+4; ++e)
@@ -79,4 +79,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound_comp.pass.cpp
index 0190e0f2120..b9133028d9a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/lower.bound/lower_bound_comp.pass.cpp
@@ -64,7 +64,7 @@ test()
         test(Iter(v.data()), Iter(v.data()+v.size()), x);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {3, 2, 1, 0};
     for (int* e = d; e <= d+4; ++e)
@@ -79,4 +79,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound.pass.cpp
index 6748b5ec4a8..1f9babde5ec 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound.pass.cpp
@@ -61,7 +61,7 @@ test()
         test(Iter(v.data()), Iter(v.data()+v.size()), x);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {0, 1, 2, 3};
     for (int* e = d; e <= d+4; ++e)
@@ -76,4 +76,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound_comp.pass.cpp
index 5cbb01abee7..86066a620bb 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.binary.search/upper.bound/upper_bound_comp.pass.cpp
@@ -64,7 +64,7 @@ test()
         test(Iter(v.data()), Iter(v.data()+v.size()), x);
 }
 
-int main()
+int main(int, char**)
 {
     int d[] = {3, 2, 1, 0};
     for (int* e = d; e <= d+4; ++e)
@@ -79,4 +79,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp
index 4fd10376fa2..482af9ef331 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.comp.pass.cpp
@@ -38,7 +38,7 @@ test(const T& v, const T& lo, const T& hi, C c, const T& x)
     assert(&std::clamp(v, lo, hi, c) == &x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -123,4 +123,6 @@ int main()
     static_assert(std::clamp(x, y, z, std::greater<T>()) == y, "" );
     static_assert(std::clamp(y, x, z, std::greater<T>()) == y, "" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp
index 96c3b43df47..4066a39453e 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.clamp/clamp.pass.cpp
@@ -36,7 +36,7 @@ test(const T& a, const T& lo, const T& hi, const T& x)
     assert(&std::clamp(a, lo, hi) == &x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -121,4 +121,6 @@ int main()
     static_assert(std::clamp(x, y, z) == x, "" );
     static_assert(std::clamp(y, x, z) == x, "" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap.pass.cpp
index ec78c10af77..14b1d1754f2 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap.pass.cpp
@@ -525,11 +525,13 @@ void test()
     assert(std::is_heap(i246, i246+7) == (std::is_heap_until(i246, i246+7) == i246+7));
 }
 
-int main()
+int main(int, char**)
 {
     test();
 
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_comp.pass.cpp
index b48db542340..9e344588239 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_comp.pass.cpp
@@ -526,11 +526,13 @@ void test()
     assert(std::is_heap(i246, i246+7, std::greater<int>()) == (std::is_heap_until(i246, i246+7, std::greater<int>()) == i246+7));
 }
 
-int main()
+int main(int, char**)
 {
     test();
 
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until.pass.cpp
index 78eb5dd70d9..b9bb3e1f5bf 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until.pass.cpp
@@ -525,11 +525,13 @@ void test()
     assert(std::is_heap_until(i246, i246+7) == i246+7);
 }
 
-int main()
+int main(int, char**)
 {
     test();
 
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until_comp.pass.cpp
index 21b21deca64..6002f662e1a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/is.heap/is_heap_until_comp.pass.cpp
@@ -526,11 +526,13 @@ void test()
     assert(std::is_heap_until(i246, i246+7, std::greater<int>()) == i246+6);
 }
 
-int main()
+int main(int, char**)
 {
     test();
 
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap.pass.cpp
index 9d2bb6e2312..3d862ca4f25 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap.pass.cpp
@@ -30,7 +30,7 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(0);
     test(1);
@@ -38,4 +38,6 @@ int main()
     test(3);
     test(10);
     test(1000);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap_comp.pass.cpp
index 18fffd41ef9..0650f745479 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/make.heap/make_heap_comp.pass.cpp
@@ -74,7 +74,7 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(0);
     test(1);
@@ -97,4 +97,6 @@ int main()
     delete [] ia;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap.pass.cpp
index 1f26f6d15b7..2b434983cfc 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap.pass.cpp
@@ -35,7 +35,9 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(1000);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap_comp.pass.cpp
index 74474be43c6..63bd1520f46 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/pop.heap/pop_heap_comp.pass.cpp
@@ -47,7 +47,7 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(1000);
 
@@ -67,4 +67,6 @@ int main()
     delete [] ia;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap.pass.cpp
index d7f681edea1..7db79e3bc5d 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap.pass.cpp
@@ -34,7 +34,9 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(1000);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap_comp.pass.cpp
index 536a2687a5e..4a47f65bfc3 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/push.heap/push_heap_comp.pass.cpp
@@ -45,7 +45,7 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(1000);
 
@@ -64,4 +64,6 @@ int main()
     delete [] ia;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap.pass.cpp
index cae2c0d9b38..947affcf086 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap.pass.cpp
@@ -31,7 +31,7 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(0);
     test(1);
@@ -39,4 +39,6 @@ int main()
     test(3);
     test(10);
     test(1000);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap_comp.pass.cpp
index 8bad526bb42..151373b7181 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.heap.operations/sort.heap/sort_heap_comp.pass.cpp
@@ -42,7 +42,7 @@ void test(int N)
     delete [] ia;
 }
 
-int main()
+int main(int, char**)
 {
     test(0);
     test(1);
@@ -64,4 +64,6 @@ int main()
     delete [] ia;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp
index 096c58ce0b7..f421bfcb8bc 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp
@@ -46,7 +46,7 @@ test()
     assert(!std::lexicographical_compare(Iter1(ib+1), Iter1(ib+3),  Iter2(ia),   Iter2(ia+sa)));
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*> >();
     test<input_iterator<const int*>, forward_iterator<const int*> >();
@@ -81,4 +81,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare_comp.pass.cpp
index 50050c50aeb..b0e0ee7d77c 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare_comp.pass.cpp
@@ -51,7 +51,7 @@ test()
     assert( std::lexicographical_compare(Iter1(ib+1), Iter1(ib+3),  Iter2(ia),   Iter2(ia+sa), c));
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*> >();
     test<input_iterator<const int*>, forward_iterator<const int*> >();
@@ -86,4 +86,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp
index ebe7307289b..20822141681 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp
@@ -96,7 +96,7 @@ test()
     test<Iter>(1000);
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
@@ -107,4 +107,6 @@ int main()
     test<random_access_iterator<S*> >();
     test<S*>();
 #endif  // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp
index ce26335cb79..7ab5c0ca922 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp
@@ -135,7 +135,7 @@ void test_PR31166 ()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
@@ -167,4 +167,6 @@ int main()
 #endif  // TEST_STD_VER >= 11
 
     test_PR31166();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge.pass.cpp
index f373f04946b..6c6f0c46d44 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge.pass.cpp
@@ -89,7 +89,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -245,4 +245,6 @@ int main()
 //  Not yet - waiting on std::copy
 //     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge_comp.pass.cpp
index c4fd0746b4b..508a4f5ab73 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.merge/merge_comp.pass.cpp
@@ -100,7 +100,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -256,4 +256,6 @@ int main()
 //  Not yet - waiting on std::copy
 //     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max.pass.cpp
index 773e14c4668..f52c72b14ce 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max.pass.cpp
@@ -24,7 +24,7 @@ test(const T& a, const T& b, const T& x)
     assert(&std::max(a, b) == &x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -52,4 +52,6 @@ int main()
     static_assert(std::max(y, x) == x, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_comp.pass.cpp
index 8488f70033d..e554b3cd038 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_comp.pass.cpp
@@ -26,7 +26,7 @@ test(const T& a, const T& b, C c, const T& x)
     assert(&std::max(a, b, c) == &x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -54,4 +54,6 @@ int main()
     static_assert(std::max(y, x, std::greater<int>()) == y, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element.pass.cpp
index c6e9e634b1d..cb5341ca047 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element.pass.cpp
@@ -71,7 +71,7 @@ void constexpr_test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -79,4 +79,6 @@ int main()
     test<const int*>();
 
     constexpr_test ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element_comp.pass.cpp
index 0a7d6ef6a8a..fbcea97b636 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_element_comp.pass.cpp
@@ -91,7 +91,7 @@ void constexpr_test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -100,4 +100,6 @@ int main()
     test_eq();
 
     constexpr_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list.pass.cpp
index 560051e3167..ff58ba479bd 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     int i = std::max({2, 3, 1});
     assert(i == 3);
@@ -40,4 +40,6 @@ int main()
     static_assert(std::max({3, 2, 1}) == 3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list_comp.pass.cpp
index 0cdab3aa46a..4042f48af5b 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/max_init_list_comp.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     int i = std::max({2, 3, 1}, std::greater<int>());
     assert(i == 1);
@@ -41,4 +41,6 @@ int main()
     static_assert(std::max({3, 2, 1}, std::greater<int>()) == 1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min.pass.cpp
index a34cb31e7be..533077a55ae 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min.pass.cpp
@@ -24,7 +24,7 @@ test(const T& a, const T& b, const T& x)
     assert(&std::min(a, b) == &x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -52,4 +52,6 @@ int main()
     static_assert(std::min(y, x) == y, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_comp.pass.cpp
index 4a815dc0be9..4524fe47b80 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_comp.pass.cpp
@@ -26,7 +26,7 @@ test(const T& a, const T& b, C c, const T& x)
     assert(&std::min(a, b, c) == &x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -54,4 +54,6 @@ int main()
     static_assert(std::min(y, x, std::greater<int>()) == x, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element.pass.cpp
index b208096d4df..151bfa8127a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element.pass.cpp
@@ -71,7 +71,7 @@ void constexpr_test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -79,4 +79,6 @@ int main()
     test<const int*>();
 
     constexpr_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element_comp.pass.cpp
index 89a9227bd25..cada8b346c7 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element_comp.pass.cpp
@@ -91,7 +91,7 @@ void constexpr_test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -100,4 +100,6 @@ int main()
     test_eq();
 
     constexpr_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list.pass.cpp
index ba8da8dfa39..1253e1a6fff 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     int i = std::min({2, 3, 1});
     assert(i == 1);
@@ -40,4 +40,6 @@ int main()
     static_assert(std::min({3, 2, 1}) == 1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list_comp.pass.cpp
index e5f372367ac..b0bd5d492fd 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list_comp.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     int i = std::min({2, 3, 1}, std::greater<int>());
     assert(i == 3);
@@ -41,4 +41,6 @@ int main()
     static_assert(std::min({3, 2, 1}, std::greater<int>()) == 3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax.pass.cpp
index e7c2ffd5fdf..0dffd52742c 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax.pass.cpp
@@ -26,7 +26,7 @@ test(const T& a, const T& b, const T& x, const T& y)
     assert(&p.second == &y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -60,4 +60,6 @@ int main()
     static_assert(p2.second == x, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_comp.pass.cpp
index 8eb059119bf..38ee5a96e52 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_comp.pass.cpp
@@ -29,7 +29,7 @@ test(const T& a, const T& b, C c, const T& x, const T& y)
 }
 
 
-int main()
+int main(int, char**)
 {
     {
     int x = 0;
@@ -63,4 +63,6 @@ int main()
     static_assert(p2.second == y, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp
index 14e7b0c0658..8b56ac180e5 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp
@@ -89,7 +89,7 @@ void constexpr_test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -97,4 +97,6 @@ int main()
     test<const int*>();
 
    constexpr_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element_comp.pass.cpp
index ba7912ed3de..3ecc02ce10e 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_element_comp.pass.cpp
@@ -96,7 +96,7 @@ void constexpr_test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -104,4 +104,6 @@ int main()
     test<const int*>();
 
     constexpr_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list.pass.cpp
index 477a0b893e0..e02b9fb38b3 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert((std::minmax({1, 2, 3}) == std::pair<int, int>(1, 3)));
     assert((std::minmax({1, 3, 2}) == std::pair<int, int>(1, 3)));
@@ -37,4 +37,6 @@ int main()
     static_assert((std::minmax({3, 2, 1}) == std::pair<int, int>(1, 3)), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list_comp.pass.cpp
index 0b834257a55..efa0e92fb95 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/minmax_init_list_comp.pass.cpp
@@ -35,7 +35,7 @@ void test_all_equal(std::initializer_list<int> il)
     assert(pred.count() <= ((3 * il.size()) / 2));
 }
 
-int main()
+int main(int, char**)
 {
     assert((std::minmax({1, 2, 3}, std::greater<int>()) == std::pair<int, int>(3, 1)));
     assert((std::minmax({1, 3, 2}, std::greater<int>()) == std::pair<int, int>(3, 1)));
@@ -72,4 +72,6 @@ int main()
     static_assert((std::minmax({3, 2, 1}, std::greater<int>()) == std::pair<int, int>(3, 1)), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/requires_forward_iterator.fail.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/requires_forward_iterator.fail.cpp
index d19304458c4..e048501753f 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/requires_forward_iterator.fail.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/requires_forward_iterator.fail.cpp
@@ -16,7 +16,7 @@
 
 #include "test_iterators.h"
 
-int main() {
+int main(int, char**) {
   int arr[] = {1, 2, 3};
   const int *b = std::begin(arr), *e = std::end(arr);
   typedef input_iterator<const int*> Iter;
@@ -33,4 +33,6 @@ int main() {
     std::minmax_element(Iter(b), Iter(e));
   }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element.pass.cpp
index b331239f1f4..abde620d038 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element.pass.cpp
@@ -50,7 +50,7 @@ test(int N)
     test_one(N, N-1);
 }
 
-int main()
+int main(int, char**)
 {
     int d = 0;
     std::nth_element(&d, &d, &d);
@@ -62,4 +62,6 @@ int main()
     test(997);
     test(1000);
     test(1009);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element_comp.pass.cpp
index 5f46394278c..980b2b9881b 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.nth.element/nth_element_comp.pass.cpp
@@ -63,7 +63,7 @@ test(int N)
     test_one(N, N-1);
 }
 
-int main()
+int main(int, char**)
 {
     int d = 0;
     std::nth_element(&d, &d, &d);
@@ -85,4 +85,6 @@ int main()
     assert(static_cast<std::size_t>(*v[v.size()/2]) == v.size()/2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation.pass.cpp
index 74cd21c5c5b..62d5b42e23e 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation.pass.cpp
@@ -57,9 +57,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation_comp.pass.cpp
index fed1a2c51eb..4416ed1e4a8 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/next_permutation_comp.pass.cpp
@@ -59,9 +59,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation.pass.cpp
index 6f11ebda077..044a6444ab0 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation.pass.cpp
@@ -57,9 +57,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation_comp.pass.cpp
index 1c78728a53d..760daae36ba 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.permutation.generators/prev_permutation_comp.pass.cpp
@@ -59,9 +59,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes.pass.cpp
index 72f80df566d..f8e8884085d 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes.pass.cpp
@@ -62,7 +62,7 @@ test()
     assert(!std::includes(Iter1(ia), Iter1(ia+sa), Iter2(id), Iter2(id+4)));
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*> >();
     test<input_iterator<const int*>, forward_iterator<const int*> >();
@@ -97,4 +97,6 @@ int main()
 #if TEST_STD_VER > 17
    static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes_comp.pass.cpp
index 5d959a0a855..48bafcb3a84 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/includes/includes_comp.pass.cpp
@@ -65,7 +65,7 @@ test()
     assert(!std::includes(Iter1(ia), Iter1(ia+sa), Iter2(id), Iter2(id+4), std::less<int>()));
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*> >();
     test<input_iterator<const int*>, forward_iterator<const int*> >();
@@ -100,4 +100,6 @@ int main()
 #if TEST_STD_VER > 17
    static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference.pass.cpp
index 576b2889aab..4d1f537b7f1 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference.pass.cpp
@@ -45,7 +45,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), irr, irr+srr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -196,4 +196,6 @@ int main()
     test<const int*, const int*, bidirectional_iterator<int*> >();
     test<const int*, const int*, random_access_iterator<int*> >();
     test<const int*, const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference_comp.pass.cpp
index 8b2f1c0494c..2597174c606 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.difference/set_difference_comp.pass.cpp
@@ -47,7 +47,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), irr, irr+srr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -198,4 +198,6 @@ int main()
     test<const int*, const int*, bidirectional_iterator<int*> >();
     test<const int*, const int*, random_access_iterator<int*> >();
     test<const int*, const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection.pass.cpp
index 84b5aa0a96c..08e08f672ae 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection.pass.cpp
@@ -62,7 +62,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -217,4 +217,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection_comp.pass.cpp
index 0511d77f844..acdd7b0191b 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.intersection/set_intersection_comp.pass.cpp
@@ -65,7 +65,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -220,4 +220,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference.pass.cpp
index e869169b39b..c74d6623bc5 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference.pass.cpp
@@ -44,7 +44,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -195,4 +195,6 @@ int main()
     test<const int*, const int*, bidirectional_iterator<int*> >();
     test<const int*, const int*, random_access_iterator<int*> >();
     test<const int*, const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference_comp.pass.cpp
index a429e59bbc6..99e75b1224a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.symmetric.difference/set_symmetric_difference_comp.pass.cpp
@@ -48,7 +48,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -199,4 +199,6 @@ int main()
     test<const int*, const int*, bidirectional_iterator<int*> >();
     test<const int*, const int*, random_access_iterator<int*> >();
     test<const int*, const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union.pass.cpp
index bc517543815..827c2c19001 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union.pass.cpp
@@ -43,7 +43,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -194,4 +194,6 @@ int main()
     test<const int*, const int*, bidirectional_iterator<int*> >();
     test<const int*, const int*, random_access_iterator<int*> >();
     test<const int*, const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_comp.pass.cpp
index 8ce76754c46..c8d1d28828c 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_comp.pass.cpp
@@ -45,7 +45,7 @@ test()
     assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
@@ -196,4 +196,6 @@ int main()
     test<const int*, const int*, bidirectional_iterator<int*> >();
     test<const int*, const int*, random_access_iterator<int*> >();
     test<const int*, const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_move.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_move.pass.cpp
index 7af3f23ff43..45bd455bb81 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_move.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.set.operations/set.union/set_union_move.pass.cpp
@@ -28,7 +28,7 @@
 #include "MoveOnly.h"
 
 
-int main()
+int main(int, char**)
 {
     std::vector<MoveOnly> lhs, rhs;
     lhs.push_back(MoveOnly(2));
@@ -42,4 +42,6 @@ int main()
 
     assert(res.size() == 1);
     assert(res[0].get() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted.pass.cpp
index f500aeb0c5a..6e2ea5f3aed 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted.pass.cpp
@@ -182,7 +182,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -192,4 +192,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_comp.pass.cpp
index 5a490977b6b..c5624d994d6 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_comp.pass.cpp
@@ -183,7 +183,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -193,4 +193,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until.pass.cpp
index 726772c5b78..4396a4fc820 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until.pass.cpp
@@ -182,7 +182,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -192,4 +192,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until_comp.pass.cpp
index cb20c0cbad4..48696cf0838 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/is.sorted/is_sorted_until_comp.pass.cpp
@@ -183,7 +183,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
@@ -193,4 +193,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy.pass.cpp
index ddea611b158..45a6fef6701 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy.pass.cpp
@@ -75,7 +75,7 @@ test()
     test_larger_sorts<Iter>(1009);
 }
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::partial_sort_copy(&i, &i, &i, &i+5);
@@ -85,4 +85,6 @@ int main()
     test<bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*> >();
     test<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy_comp.pass.cpp
index d3e30b9d04b..a1c2b0f9c8a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort.copy/partial_sort_copy_comp.pass.cpp
@@ -79,7 +79,7 @@ test()
     test_larger_sorts<Iter>(1009);
 }
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::partial_sort_copy(&i, &i, &i, &i+5);
@@ -89,4 +89,6 @@ int main()
     test<bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*> >();
     test<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort.pass.cpp
index 7e52c5747f8..b41eb12d6aa 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort.pass.cpp
@@ -53,7 +53,7 @@ test_larger_sorts(int N)
     test_larger_sorts(N, N);
 }
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::partial_sort(&i, &i, &i);
@@ -66,4 +66,6 @@ int main()
     test_larger_sorts(997);
     test_larger_sorts(1000);
     test_larger_sorts(1009);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort_comp.pass.cpp
index e1143f592f9..f50d04005a4 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort_comp.pass.cpp
@@ -66,7 +66,7 @@ test_larger_sorts(int N)
     test_larger_sorts(N, N);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int i = 0;
@@ -92,4 +92,6 @@ int main()
         assert(*v[i] == i);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort.pass.cpp
index c65f13c0748..8f2845732cc 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort.pass.cpp
@@ -130,7 +130,7 @@ test_larger_sorts(int N)
     test_larger_sorts(N, N);
 }
 
-int main()
+int main(int, char**)
 {
     // test null range
     int d = 0;
@@ -152,4 +152,6 @@ int main()
     test_larger_sorts(997);
     test_larger_sorts(1000);
     test_larger_sorts(1009);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort_comp.pass.cpp
index e6896bea416..832d190ce47 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/sort/sort_comp.pass.cpp
@@ -30,7 +30,7 @@ struct indirect_less
         {return *x < *y;}
 };
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<int> v(1000);
@@ -53,4 +53,6 @@ int main()
     assert(*v[2] == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort.pass.cpp
index 9341d699410..c433baab44a 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort.pass.cpp
@@ -130,7 +130,7 @@ test_larger_sorts(int N)
     test_larger_sorts(N, N);
 }
 
-int main()
+int main(int, char**)
 {
     // test null range
     int d = 0;
@@ -152,4 +152,6 @@ int main()
     test_larger_sorts(997);
     test_larger_sorts(1000);
     test_larger_sorts(1009);
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort_comp.pass.cpp
index 6c5dcabfe32..8da2b964b7e 100644
--- a/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.sort/stable.sort/stable_sort_comp.pass.cpp
@@ -66,7 +66,7 @@ void test()
     assert(std::is_sorted(v.begin(), v.end()));
 }
 
-int main()
+int main(int, char**)
 {
     test();
 
@@ -82,4 +82,6 @@ int main()
     assert(*v[2] == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/alg.sorting/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/alg.sorting/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/algorithms/algorithms.general/nothing_to_do.pass.cpp b/libcxx/test/std/algorithms/algorithms.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/algorithms/algorithms.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/algorithms/algorithms.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.fences/atomic_signal_fence.pass.cpp b/libcxx/test/std/atomics/atomics.fences/atomic_signal_fence.pass.cpp
index ae4af5c9750..bf5325940e4 100644
--- a/libcxx/test/std/atomics/atomics.fences/atomic_signal_fence.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.fences/atomic_signal_fence.pass.cpp
@@ -14,7 +14,9 @@
 
 #include <atomic>
 
-int main()
+int main(int, char**)
 {
     std::atomic_signal_fence(std::memory_order_seq_cst);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.fences/atomic_thread_fence.pass.cpp b/libcxx/test/std/atomics/atomics.fences/atomic_thread_fence.pass.cpp
index 91aeff28238..d237f2de118 100644
--- a/libcxx/test/std/atomics/atomics.fences/atomic_thread_fence.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.fences/atomic_thread_fence.pass.cpp
@@ -14,7 +14,9 @@
 
 #include <atomic>
 
-int main()
+int main(int, char**)
 {
     std::atomic_thread_fence(std::memory_order_seq_cst);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear.pass.cpp b/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear.pass.cpp
index 846d86e7a6b..23cb3d2b6fa 100644
--- a/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear.pass.cpp
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::atomic_flag f;
@@ -34,4 +34,6 @@ int main()
         atomic_flag_clear(&f);
         assert(f.test_and_set() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear_explicit.pass.cpp
index 104c22b57c0..d87291297ee 100644
--- a/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/atomic_flag_clear_explicit.pass.cpp
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::atomic_flag f; // uninitialized first
@@ -62,4 +62,6 @@ int main()
         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
         assert(f.test_and_set() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set.pass.cpp b/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set.pass.cpp
index 009c859ffe4..d73dc316d96 100644
--- a/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set.pass.cpp
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::atomic_flag f;
@@ -32,4 +32,6 @@ int main()
         assert(atomic_flag_test_and_set(&f) == 0);
         assert(f.test_and_set() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set_explicit.pass.cpp
index 3a40328be84..972a6e84b6f 100644
--- a/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/atomic_flag_test_and_set_explicit.pass.cpp
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::atomic_flag f;
@@ -92,4 +92,6 @@ int main()
         assert(atomic_flag_test_and_set_explicit(&f, std::memory_order_seq_cst) == 0);
         assert(f.test_and_set() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp b/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp
index cc877a477b1..33378e4bd87 100644
--- a/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::atomic_flag f; // uninitialized
@@ -76,4 +76,6 @@ int main()
         f.clear(std::memory_order_seq_cst);
         assert(f.test_and_set() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/copy_assign.fail.cpp b/libcxx/test/std/atomics/atomics.flag/copy_assign.fail.cpp
index 9fa766cad2c..aa5a24b9e90 100644
--- a/libcxx/test/std/atomics/atomics.flag/copy_assign.fail.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/copy_assign.fail.cpp
@@ -15,9 +15,11 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::atomic_flag f0;
     std::atomic_flag f;
     f = f0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/copy_ctor.fail.cpp b/libcxx/test/std/atomics/atomics.flag/copy_ctor.fail.cpp
index f167651c925..10deaf1256d 100644
--- a/libcxx/test/std/atomics/atomics.flag/copy_ctor.fail.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/copy_ctor.fail.cpp
@@ -15,8 +15,10 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::atomic_flag f0;
     std::atomic_flag f(f0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/copy_volatile_assign.fail.cpp b/libcxx/test/std/atomics/atomics.flag/copy_volatile_assign.fail.cpp
index 128778ab92f..a453fab2876 100644
--- a/libcxx/test/std/atomics/atomics.flag/copy_volatile_assign.fail.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/copy_volatile_assign.fail.cpp
@@ -15,9 +15,11 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::atomic_flag f0;
     volatile std::atomic_flag f;
     f = f0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/default.pass.cpp b/libcxx/test/std/atomics/atomics.flag/default.pass.cpp
index 515e8108c1b..6a0d907fde9 100644
--- a/libcxx/test/std/atomics/atomics.flag/default.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/default.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::atomic_flag f;
     f.clear();
@@ -32,4 +32,6 @@ int main()
         assert(!zero.test_and_set());
         zero.~A();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/init.pass.cpp b/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
index 8ca3bc9ccda..a45784d802b 100644
--- a/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
@@ -18,8 +18,10 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::atomic_flag f = ATOMIC_FLAG_INIT;
     assert(f.test_and_set() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.flag/test_and_set.pass.cpp b/libcxx/test/std/atomics/atomics.flag/test_and_set.pass.cpp
index d567734d146..1a198c1be84 100644
--- a/libcxx/test/std/atomics/atomics.flag/test_and_set.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/test_and_set.pass.cpp
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::atomic_flag f;
@@ -104,4 +104,6 @@ int main()
         assert(f.test_and_set(std::memory_order_seq_cst) == 0);
         assert(f.test_and_set(std::memory_order_seq_cst) == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.general/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.general/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.general/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.general/replace_failure_order.pass.cpp b/libcxx/test/std/atomics/atomics.general/replace_failure_order.pass.cpp
index b246fc016fb..ee23841382b 100644
--- a/libcxx/test/std/atomics/atomics.general/replace_failure_order.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.general/replace_failure_order.pass.cpp
@@ -23,7 +23,7 @@
 
 #include <atomic>
 
-int main() {
+int main(int, char**) {
     std::atomic<int> i;
     volatile std::atomic<int> v;
     int exp = 0;
diff --git a/libcxx/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp b/libcxx/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
index 5d1f3ba9a7c..d2ce1cefd28 100644
--- a/libcxx/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
@@ -134,4 +134,4 @@ void run()
     static_assert(std::atomic<std::nullptr_t>::is_always_lock_free == (2 == ATOMIC_POINTER_LOCK_FREE));
 }
 
-int main() { run(); }
+int main(int, char**) { run(); return 0; }
diff --git a/libcxx/test/std/atomics/atomics.lockfree/lockfree.pass.cpp b/libcxx/test/std/atomics/atomics.lockfree/lockfree.pass.cpp
index cc448e66288..b86893e0b9c 100644
--- a/libcxx/test/std/atomics/atomics.lockfree/lockfree.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.lockfree/lockfree.pass.cpp
@@ -24,7 +24,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(ATOMIC_BOOL_LOCK_FREE == 0 ||
            ATOMIC_BOOL_LOCK_FREE == 1 ||
@@ -56,4 +56,6 @@ int main()
     assert(ATOMIC_POINTER_LOCK_FREE == 0 ||
            ATOMIC_POINTER_LOCK_FREE == 1 ||
            ATOMIC_POINTER_LOCK_FREE == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.order/kill_dependency.pass.cpp b/libcxx/test/std/atomics/atomics.order/kill_dependency.pass.cpp
index 144bf505907..998b0cef38b 100644
--- a/libcxx/test/std/atomics/atomics.order/kill_dependency.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.order/kill_dependency.pass.cpp
@@ -15,8 +15,10 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::kill_dependency(5) == 5);
     assert(std::kill_dependency(-5.5) == -5.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.order/memory_order.pass.cpp b/libcxx/test/std/atomics/atomics.order/memory_order.pass.cpp
index 69a46eac3d1..973f58583ca 100644
--- a/libcxx/test/std/atomics/atomics.order/memory_order.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.order/memory_order.pass.cpp
@@ -19,7 +19,7 @@
 #include <atomic>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::memory_order_relaxed == 0);
     assert(std::memory_order_consume == 1);
@@ -29,4 +29,6 @@ int main()
     assert(std::memory_order_seq_cst == 5);
     std::memory_order o = std::memory_order_seq_cst;
     assert(o == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.syn/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.syn/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.syn/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.syn/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/address.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/address.pass.cpp
index 98c8d4f24a2..598889736ab 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/address.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/address.pass.cpp
@@ -136,7 +136,9 @@ void test()
     do_test<volatile A, T>();
 }
 
-int main()
+int main(int, char**)
 {
     test<std::atomic<int*>, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/bool.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/bool.pass.cpp
index 33901ce9b31..154d0bfe67d 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/bool.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/bool.pass.cpp
@@ -58,7 +58,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         volatile std::atomic<bool> obj(true);
@@ -232,4 +232,6 @@ int main()
         assert(zero == false);
         zero.~A();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/cstdint_typedefs.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/cstdint_typedefs.pass.cpp
index 0c76e7b0fd6..a0648ff9c0a 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/cstdint_typedefs.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/cstdint_typedefs.pass.cpp
@@ -39,7 +39,7 @@
 #include <type_traits>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::atomic<  std::int_least8_t>,   std::atomic_int_least8_t>::value), "");
     static_assert((std::is_same<std::atomic< std::uint_least8_t>,  std::atomic_uint_least8_t>::value), "");
@@ -65,4 +65,6 @@ int main()
     static_assert((std::is_same<std::atomic<std::ptrdiff_t>, std::atomic_ptrdiff_t>::value), "");
     static_assert((std::is_same<std::atomic< std::intmax_t>,  std::atomic_intmax_t>::value), "");
     static_assert((std::is_same<std::atomic<std::uintmax_t>, std::atomic_uintmax_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/integral.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/integral.pass.cpp
index e59bee43c55..62ef06bcc16 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/integral.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/integral.pass.cpp
@@ -167,7 +167,7 @@ void test()
 }
 
 
-int main()
+int main(int, char**)
 {
     test<std::atomic_char, char>();
     test<std::atomic_schar, signed char>();
@@ -220,4 +220,6 @@ int main()
     test<volatile std::atomic_uint32_t, uint32_t>();
     test<volatile std::atomic_int64_t,   int64_t>();
     test<volatile std::atomic_uint64_t, uint64_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/integral_typedefs.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/integral_typedefs.pass.cpp
index d63043b8473..faa682b8cef 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/integral_typedefs.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/integral_typedefs.pass.cpp
@@ -40,7 +40,7 @@
 #include <atomic>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::atomic<char>, std::atomic_char>::value), "");
     static_assert((std::is_same<std::atomic<signed char>, std::atomic_schar>::value), "");
@@ -71,4 +71,6 @@ int main()
     static_assert((std::is_same<std::atomic<uint32_t>,  std::atomic_uint32_t>::value), "");
     static_assert((std::is_same<std::atomic<int64_t>,   std::atomic_int64_t>::value), "");
     static_assert((std::is_same<std::atomic<uint64_t>,  std::atomic_uint64_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.fail.cpp b/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.fail.cpp
index 6ea65495c43..3ec8ed25c97 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.fail.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.fail.cpp
@@ -63,7 +63,9 @@ void test ( T t ) {
     std::atomic<T> t0(t);
 }
 
-int main()
+int main(int, char**)
 {
     test(NotTriviallyCopyable(42));
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.pass.cpp b/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.pass.cpp
index 03c68de8658..229761eb326 100644
--- a/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.pass.cpp
@@ -68,9 +68,11 @@ void test ( T t ) {
     std::atomic<T> t0(t);
     }
 
-int main()
+int main(int, char**)
 {
     test(TriviallyCopyable(42));
     test(std::this_thread::get_id());
     test(std::chrono::nanoseconds(2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.arith/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.arith/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.arith/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.arith/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.general/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.general/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.general/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.pointer/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.pointer/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.pointer/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.pointer/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong.pass.cpp
index 8d96adeea74..041845d5be2 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong.pass.cpp
@@ -55,7 +55,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong_explicit.pass.cpp
index b557817d690..99a85088633 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong_explicit.pass.cpp
@@ -62,7 +62,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak.pass.cpp
index 53f4174ec86..a2a9e205db8 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak.pass.cpp
@@ -56,7 +56,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak_explicit.pass.cpp
index 7edfb91cdc6..2ad17f1cbe6 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak_explicit.pass.cpp
@@ -64,7 +64,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange.pass.cpp
index 43e6b804ba2..d13238e6528 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange.pass.cpp
@@ -41,7 +41,9 @@ struct TestFn {
 };
 
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange_explicit.pass.cpp
index 14e8ed1af60..2acbcb20f7c 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange_explicit.pass.cpp
@@ -43,7 +43,9 @@ struct TestFn {
 };
 
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add.pass.cpp
index deb68b170e4..f84a4898348 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add.pass.cpp
@@ -74,9 +74,11 @@ void testp()
     }
 }
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add_explicit.pass.cpp
index a75acb34118..fbdf3fffcd7 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add_explicit.pass.cpp
@@ -79,9 +79,11 @@ testp()
     }
 }
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and.pass.cpp
index f80d7a82c5d..dfaaaa3e5b4 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and.pass.cpp
@@ -44,7 +44,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and_explicit.pass.cpp
index 77a89dc79e7..d31245a8421 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and_explicit.pass.cpp
@@ -46,7 +46,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or.pass.cpp
index 19c321539e3..741dca00e86 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or.pass.cpp
@@ -44,7 +44,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or_explicit.pass.cpp
index af0a7e8ab8c..e56e946f43c 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or_explicit.pass.cpp
@@ -46,7 +46,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub.pass.cpp
index 8298327a994..13fde4ad6a7 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub.pass.cpp
@@ -74,9 +74,11 @@ void testp()
     }
 }
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub_explicit.pass.cpp
index b7447ad7a72..af97bcc6022 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub_explicit.pass.cpp
@@ -79,9 +79,11 @@ void testp()
     }
 }
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor.pass.cpp
index 5eaf5039faa..0e6f99f3629 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor.pass.cpp
@@ -44,7 +44,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor_explicit.pass.cpp
index 83ac8dbe52f..ece15694561 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor_explicit.pass.cpp
@@ -46,7 +46,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachIntegralType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_init.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_init.pass.cpp
index bcb729469fb..0e5b920f91e 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_init.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_init.pass.cpp
@@ -38,7 +38,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_is_lock_free.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_is_lock_free.pass.cpp
index e8352cd8e3c..bfa24dae562 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_is_lock_free.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_is_lock_free.pass.cpp
@@ -40,8 +40,10 @@ struct A
     char _[4];
 };
 
-int main()
+int main(int, char**)
 {
     TestFn<A>()();
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load.pass.cpp
index 9431331d676..b775c546737 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load.pass.cpp
@@ -38,7 +38,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load_explicit.pass.cpp
index d6cf0860502..0384baa5a7f 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load_explicit.pass.cpp
@@ -38,7 +38,9 @@ struct TestFn {
   }
 };
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store.pass.cpp
index 6f91792fba6..0fb3bc7dda9 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store.pass.cpp
@@ -38,7 +38,9 @@ struct TestFn {
 };
 
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store_explicit.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store_explicit.pass.cpp
index c63c5cc1bbb..11aa295dee4 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store_explicit.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store_explicit.pass.cpp
@@ -38,7 +38,9 @@ struct TestFn {
 };
 
 
-int main()
+int main(int, char**)
 {
     TestEachAtomicType<TestFn>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp
index 9111d8bd037..1588af3273f 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp
@@ -17,8 +17,10 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::atomic<int> v = ATOMIC_VAR_INIT(5);
     assert(v == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp
index 563a053373e..d692e931b49 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp
@@ -56,8 +56,10 @@ struct TestFunc {
 };
 
 
-int main()
+int main(int, char**)
 {
     TestFunc<UserType>()();
     TestEachIntegralType<TestFunc>()();
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.templ/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.templ/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.templ/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.templ/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/atomics/atomics.types.operations/nothing_to_do.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/atomics/atomics.types.operations/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/iterator_types.pass.cpp b/libcxx/test/std/containers/associative/iterator_types.pass.cpp
index f18fa2b4fc4..1b8556fb558 100644
--- a/libcxx/test/std/containers/associative/iterator_types.pass.cpp
+++ b/libcxx/test/std/containers/associative/iterator_types.pass.cpp
@@ -50,7 +50,7 @@ void testSet() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef std::map<int, int> Map;
     typedef std::pair<const int, int> ValueTp;
@@ -127,4 +127,6 @@ int main() {
     testSet<Set, ValueTp, min_pointer<const ValueTp>>();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/PR28469_undefined_behavior_segfault.sh.cpp b/libcxx/test/std/containers/associative/map/PR28469_undefined_behavior_segfault.sh.cpp
index ff0be20842d..030fdaf3918 100644
--- a/libcxx/test/std/containers/associative/map/PR28469_undefined_behavior_segfault.sh.cpp
+++ b/libcxx/test/std/containers/associative/map/PR28469_undefined_behavior_segfault.sh.cpp
@@ -24,7 +24,9 @@ struct F {
     F() { m[42] = &dummy; }
 };
 
-int main() {
+int main(int, char**) {
     F f;
     f = F();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/associative/map/allocator_mismatch.fail.cpp
index 08f5ee94fb0..faec5aa401e 100644
--- a/libcxx/test/std/containers/associative/map/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <map>
 
-int main()
+int main(int, char**)
 {
     std::map<int, int, std::less<int>, std::allocator<long> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/compare.pass.cpp b/libcxx/test/std/containers/associative/map/compare.pass.cpp
index fedc9d2b3a1..84de271842b 100644
--- a/libcxx/test/std/containers/associative/map/compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/compare.pass.cpp
@@ -24,7 +24,7 @@ struct Key {
   bool operator< (const Key&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::map<Key, int> MapT;
     typedef MapT::iterator Iter;
@@ -48,4 +48,6 @@ int main()
         assert(!result2.second);
         assert(map[Key(0)] == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/gcc_workaround.pass.cpp b/libcxx/test/std/containers/associative/map/gcc_workaround.pass.cpp
index 622449facc1..9e05b66a5eb 100644
--- a/libcxx/test/std/containers/associative/map/gcc_workaround.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/gcc_workaround.pass.cpp
@@ -15,7 +15,4 @@ std::map<int,int>::iterator it;
 using std::set;
 using std::multiset;
 
-int main(void)
-{
-       return 0;
-}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/containers/associative/map/incomplete_type.pass.cpp b/libcxx/test/std/containers/associative/map/incomplete_type.pass.cpp
index 1bc320e9cbf..a45c50c3294 100644
--- a/libcxx/test/std/containers/associative/map/incomplete_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/incomplete_type.pass.cpp
@@ -23,6 +23,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 inline bool operator<(A const& L, A const& R)  { return L.data < R.data; }
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/at.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/at.pass.cpp
index 475dd641cc2..c13c6a64acb 100644
--- a/libcxx/test/std/containers/associative/map/map.access/at.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/at.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -160,4 +160,6 @@ int main()
         assert(m.size() == 7);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/empty.fail.cpp b/libcxx/test/std/containers/associative/map/map.access/empty.fail.cpp
index 0305fdb5684..61c4e757b0c 100644
--- a/libcxx/test/std/containers/associative/map/map.access/empty.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::map<int, int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/empty.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/empty.pass.cpp
index 1317ee31048..cff13df7af2 100644
--- a/libcxx/test/std/containers/associative/map/map.access/empty.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/empty.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double> M;
@@ -39,4 +39,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/index_key.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/index_key.pass.cpp
index 1d842205a8f..8df052e0162 100644
--- a/libcxx/test/std/containers/associative/map/map.access/index_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/index_key.pass.cpp
@@ -23,7 +23,7 @@
 #include "container_test_types.h"
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -139,4 +139,6 @@ int main()
     assert(m.size() == 8);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/index_rv_key.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/index_rv_key.pass.cpp
index 523d4e6d882..7effa0c6415 100644
--- a/libcxx/test/std/containers/associative/map/map.access/index_rv_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/index_rv_key.pass.cpp
@@ -23,7 +23,7 @@
 #include "min_allocator.h"
 #include "container_test_types.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::map<MoveOnly, double> m;
@@ -76,4 +76,6 @@ int main()
             }
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/index_tuple.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/index_tuple.pass.cpp
index 5f39bece03b..bc99f6ef8e3 100644
--- a/libcxx/test/std/containers/associative/map/map.access/index_tuple.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/index_tuple.pass.cpp
@@ -22,9 +22,11 @@
 #include <tuple>
 
 
-int main()
+int main(int, char**)
 {
     using namespace std;
     map<tuple<int,int>, size_t> m;
     m[make_tuple(2,3)]=7;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/iterator.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/iterator.pass.cpp
index c1c503733f2..39b573a1392 100644
--- a/libcxx/test/std/containers/associative/map/map.access/iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/iterator.pass.cpp
@@ -32,7 +32,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -225,4 +225,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/max_size.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/max_size.pass.cpp
index 1bb873f4b5d..b38cf114638 100644
--- a/libcxx/test/std/containers/associative/map/map.access/max_size.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   typedef std::pair<const int, int> KV;
   {
@@ -47,4 +47,6 @@ int main()
     assert(c.max_size() <= max_dist);
     assert(c.max_size() <= alloc_max_size(c.get_allocator()));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.access/size.pass.cpp b/libcxx/test/std/containers/associative/map/map.access/size.pass.cpp
index 4408dc54e64..bb4b14e026f 100644
--- a/libcxx/test/std/containers/associative/map/map.access/size.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.access/size.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double> M;
@@ -55,4 +55,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/alloc.pass.cpp
index 04000bec93e..5bb9abc88f7 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::less<int> C;
@@ -46,4 +46,6 @@ int main()
     assert(m.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/assign_initializer_list.pass.cpp
index 664d6cf083e..612838ef667 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/assign_initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -69,4 +69,6 @@ int main()
     assert(*next(m.begin()) == V(2, 1));
     assert(*next(m.begin(), 2) == V(3, 1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/compare.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/compare.pass.cpp
index 2fb00ebde7c..40a8e38aef2 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/compare.pass.cpp
@@ -20,7 +20,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > C;
@@ -38,4 +38,6 @@ int main()
     assert(m.key_comp() == C(3));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/compare_alloc.pass.cpp
index d4de57163d9..71bc32295e0 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/compare_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > C;
@@ -50,4 +50,6 @@ int main()
     assert(m.get_allocator() == A{});
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/associative/map/map.cons/compare_copy_constructible.fail.cpp
index 1e75326dee2..3c714de40af 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/compare_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::map<int, int, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/copy.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/copy.pass.cpp
index 0e7266d59db..8eec27b3eab 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/copy.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -126,4 +126,6 @@ int main()
         assert(*next(mo.begin(), 2) == V(3, 1));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/copy_alloc.pass.cpp
index 0e01b3674df..d25504382e4 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/copy_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -125,4 +125,6 @@ int main()
     assert(*next(mo.begin(), 2) == V(3, 1));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/copy_assign.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/copy_assign.pass.cpp
index e63cbe951fa..a902e05603b 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/copy_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/copy_assign.pass.cpp
@@ -108,7 +108,7 @@ bool balanced_allocs() {
     }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -337,4 +337,6 @@ int main()
     }
     assert(balanced_allocs());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/default.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/default.pass.cpp
index 3a2b7fb4837..5d3fcaee117 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/default.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::map<int, double> m;
@@ -50,4 +50,6 @@ int main()
     assert(m.begin() == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/default_noexcept.pass.cpp
index 61f87b3c1c2..2e4b4242d2d 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/default_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
 #if defined(_LIBCPP_VERSION)
@@ -54,4 +54,6 @@ int main()
         typedef std::map<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp
index fb01aacf639..af8fbe79f0b 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp
@@ -23,6 +23,8 @@ struct X
     std::map<int, X>::const_reverse_iterator cri;
 };
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/dtor_noexcept.pass.cpp
index fb07754c6ac..2a2e89bf440 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_comp
     bool operator()(const T&, const T&) const noexcept { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -48,4 +48,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/initializer_list.pass.cpp
index b7f916c1119..1303f7ef2ba 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -61,4 +61,6 @@ int main()
     assert(*next(m.begin()) == V(2, 1));
     assert(*next(m.begin(), 2) == V(3, 1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare.pass.cpp
index 887597768bc..9b6a47ac334 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -63,4 +63,6 @@ int main()
     assert(*next(m.begin(), 2) == V(3, 1));
     assert(m.key_comp() == C(3));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare_alloc.pass.cpp
index 5288d64f01d..0da3115f76f 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/initializer_list_compare_alloc.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -116,4 +116,6 @@ int main()
     assert(m.key_comp() == C(3));
     assert(m.get_allocator() == a);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/iter_iter.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/iter_iter.pass.cpp
index 2a17bffb50a..243800cfd9b 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/iter_iter.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -64,4 +64,6 @@ int main()
     assert(*next(m.begin(), 2) == V(3, 1));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp.pass.cpp
index 41672578333..12a079ea01c 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -69,4 +69,6 @@ int main()
     assert(*next(m.begin(), 2) == V(3, 1));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp_alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp_alloc.pass.cpp
index c8861573a77..56396799dc9 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/iter_iter_comp_alloc.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -119,4 +119,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/move.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/move.pass.cpp
index f2f8dd8a976..ecf8c9dabfd 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/move.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -114,4 +114,6 @@ int main()
         assert(mo.size() == 0);
         assert(distance(mo.begin(), mo.end()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp
index cec9253561a..aa87e9ff07a 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp
@@ -24,7 +24,7 @@
 #include "min_allocator.h"
 #include "Counter.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<MoveOnly, MoveOnly> V;
@@ -268,4 +268,6 @@ int main()
         assert(m3.key_comp() == C(5));
         LIBCPP_ASSERT(m1.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/move_assign.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/move_assign.pass.cpp
index be06d49c958..758d0f83f86 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/move_assign.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<MoveOnly, MoveOnly> V;
@@ -184,4 +184,6 @@ int main()
         assert(m3.key_comp() == C(5));
         assert(m1.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/move_assign_noexcept.pass.cpp
index 42bc980b7e0..fcb92607163 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/move_assign_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -54,4 +54,6 @@ int main()
         typedef std::map<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/move_noexcept.pass.cpp
index dd61439ca5f..44b2b7e22b6 100644
--- a/libcxx/test/std/containers/associative/map/map.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/move_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     typedef std::pair<const MoveOnly, MoveOnly> V;
@@ -52,4 +52,6 @@ int main()
         typedef std::map<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/associative/map/map.erasure/erase_if.pass.cpp
index af7accdffc0..88a95836828 100644
--- a/libcxx/test/std/containers/associative/map/map.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.erasure/erase_if.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0<S>({1,2,3}, False, {1,2,3});
 }
 
-int main()
+int main(int, char**)
 {
     test<std::map<int, int>>();
     test<std::map<int, int, std::less<int>, min_allocator<std::pair<const int, int>>>> ();
@@ -74,5 +74,7 @@ int main()
 
     test<std::map<long, short>>();
     test<std::map<short, double>>();
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/clear.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/clear.pass.cpp
index 895a8115aa0..5c6d00e9f3a 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/clear.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, double> M;
@@ -62,4 +62,6 @@ int main()
         assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/emplace.pass.cpp
index 8680ab8213b..382e5c8badf 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/emplace.pass.cpp
@@ -23,7 +23,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, DefaultOnly> M;
@@ -159,4 +159,6 @@ int main()
         assert(m.begin()->first == 2);
         assert(m.begin()->second == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/emplace_hint.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/emplace_hint.pass.cpp
index 1c649093fe8..516d88054b7 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/emplace_hint.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, DefaultOnly> M;
@@ -154,4 +154,6 @@ int main()
         assert(m.begin()->first == 2);
         assert(m.begin()->second == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter.pass.cpp
index 57de16478fa..0f23ef63810 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter.pass.cpp
@@ -25,7 +25,7 @@ struct TemplateConstructor
 
 bool operator<(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, double> M;
@@ -255,4 +255,6 @@ int main()
             c.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter_iter.pass.cpp
index 875fab53897..71fa96ce11b 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/erase_iter_iter.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, double> M;
@@ -153,4 +153,6 @@ int main()
         assert(i == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/erase_key.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/erase_key.pass.cpp
index 23fae9a6079..da96499b09f 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/erase_key.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, double> M;
@@ -271,4 +271,6 @@ int main()
         assert(s == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/extract_iterator.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/extract_iterator.pass.cpp
index 95ba2b711b9..f2b67c9ff63 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/extract_iterator.pass.cpp
@@ -40,7 +40,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using map_type = std::map<int, int>;
@@ -63,4 +63,6 @@ int main()
         min_alloc_map m = {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {5, 5}, {6, 6}};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/extract_key.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/extract_key.pass.cpp
index 70afd45ffb6..018e9acf898 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/extract_key.pass.cpp
@@ -45,7 +45,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::map<int, int> m = {{1,1}, {2,2}, {3,3}, {4,4}, {5,5}, {6,6}};
@@ -72,4 +72,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp
index 9adb3d61957..f3e84002123 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp
@@ -21,10 +21,12 @@
 #include "container_test_types.h"
 #include "../../../map_allocator_requirement_test_templates.h"
 
-int main()
+int main(int, char**)
 {
   testMapInsert<TCT::map<> >();
   testMapInsertHint<TCT::map<> >();
   testMapEmplace<TCT::map<> >();
   testMapEmplaceHint<TCT::map<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_cv.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_cv.pass.cpp
index 50801f72183..079b0eaca01 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_cv.pass.cpp
@@ -59,7 +59,7 @@ void do_insert_cv_test()
     assert(r.first->second == 3.5);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_cv_test<std::map<int, double> >();
 #if TEST_STD_VER >= 11
@@ -68,4 +68,6 @@ int main()
         do_insert_cv_test<M>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_initializer_list.pass.cpp
index 124a40c330e..ea6c1380054 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -65,4 +65,6 @@ int main()
     assert(*next(m.begin()) == V(2, 1));
     assert(*next(m.begin(), 2) == V(3, 1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_cv.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_cv.pass.cpp
index f993bc2027f..a49a28c67bf 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_cv.pass.cpp
@@ -55,7 +55,7 @@ void do_insert_iter_cv_test()
     assert(r->second == 3.5);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_iter_cv_test<std::map<int, double> >();
 #if TEST_STD_VER >= 11
@@ -64,4 +64,6 @@ int main()
         do_insert_iter_cv_test<M>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_iter.pass.cpp
index 6315bc40ef8..a6a7763363b 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::map<int, double> M;
@@ -73,4 +73,6 @@ int main()
         assert(next(m.begin(), 2)->second == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_rv.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_rv.pass.cpp
index 45665a411c3..8cbbebe5d3c 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_iter_rv.pass.cpp
@@ -53,7 +53,7 @@ void do_insert_iter_rv_test()
     assert(r->first == 3);
     assert(r->second == 3);
 }
-int main()
+int main(int, char**)
 {
     do_insert_iter_rv_test<std::map<int, MoveOnly>, std::pair<int, MoveOnly>>();
     do_insert_iter_rv_test<std::map<int, MoveOnly>, std::pair<const int, MoveOnly>>();
@@ -94,4 +94,6 @@ int main()
         assert(r->second == 3);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type.pass.cpp
index 3ad5f46b43b..f3f1662600e 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type.pass.cpp
@@ -75,10 +75,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::map<int, int> m;
     test(m);
     std::map<int, int, std::less<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type_hint.pass.cpp
index 41d264f3f7b..084f7ee2c74 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_node_type_hint.pass.cpp
@@ -54,10 +54,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::map<int, int> m;
     test(m);
     std::map<int, int, std::less<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_or_assign.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_or_assign.pass.cpp
index 69caa8434a4..bd9625a0950 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_or_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_or_assign.pass.cpp
@@ -56,7 +56,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     { // pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);
         typedef std::map<int, Moveable> M;
@@ -181,4 +181,6 @@ int main()
         assert(r->first.get()  == 3);  // key
         assert(r->second.get() == 5);  // value
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/insert_rv.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/insert_rv.pass.cpp
index 439adfde27f..e6fb13ee32c 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/insert_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/insert_rv.pass.cpp
@@ -59,7 +59,7 @@ void do_insert_rv_test()
     assert(r.first->second == 3);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_rv_test<std::map<int, MoveOnly>, std::pair<int, MoveOnly>>();
     do_insert_rv_test<std::map<int, MoveOnly>, std::pair<const int, MoveOnly>>();
@@ -103,4 +103,6 @@ int main()
         assert(r.first->first == 3);
         assert(r.first->second == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/merge.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/merge.pass.cpp
index 1cef30944a8..ae943df6a45 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/merge.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_comparator
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::map<int, int> src{{1, 0}, {3, 0}, {5, 0}};
@@ -146,4 +146,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.modifiers/try.emplace.pass.cpp b/libcxx/test/std/containers/associative/map/map.modifiers/try.emplace.pass.cpp
index 43d5c3cac41..fe9484a3ce3 100644
--- a/libcxx/test/std/containers/associative/map/map.modifiers/try.emplace.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.modifiers/try.emplace.pass.cpp
@@ -54,7 +54,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     { // pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);
         typedef std::map<int, Moveable> M;
@@ -178,4 +178,6 @@ int main()
         assert(r->first.get()  == 3); // key
         assert(r->second.get() == 4); // value
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/count.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/count.pass.cpp
index 9ac980670de..8abae288bd8 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/count.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/count.pass.cpp
@@ -20,7 +20,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -190,4 +190,6 @@ int main()
     assert(r == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/count0.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/count0.pass.cpp
index eeaa41a00b3..cce0444fdc3 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/count0.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/count0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less> M;
@@ -35,4 +35,6 @@ int main()
     typedef std::map<int, double, transparent_less_not_referenceable> M;
     assert(M().count(C2Int{5}) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/count1.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/count1.fail.cpp
index 049ee980a8b..42dc59c2789 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/count1.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/count1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/count2.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/count2.fail.cpp
index 6b4c07572f9..1fe6b927d8d 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/count2.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/count2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/count3.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/count3.fail.cpp
index 525c57cefdd..3fd930eb254 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/count3.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/count3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/count_transparent.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/count_transparent.pass.cpp
index fb33d3b0adf..fa649024269 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/count_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/count_transparent.pass.cpp
@@ -40,10 +40,12 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::map<std::pair<int, int>, int, Comp> s{
       {{2, 1}, 1}, {{1, 2}, 2}, {{1, 3}, 3}, {{1, 4}, 4}, {{2, 2}, 5}};
 
   auto cnt = s.count(1);
   assert(cnt == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/equal_range.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/equal_range.pass.cpp
index 3c0c16fb5c2..c46e52c711c 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/equal_range.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/equal_range.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -487,4 +487,6 @@ int main()
     assert(r.second == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp
index 27dac20aed6..22f067a2a70 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less> M;
@@ -41,4 +41,6 @@ int main()
     P result = example.equal_range(C2Int{5});
     assert(result.first == result.second);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/equal_range1.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/equal_range1.fail.cpp
index 629541c1d63..f8ccfc3d8a5 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/equal_range1.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/equal_range1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/equal_range2.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/equal_range2.fail.cpp
index db3fe9eea61..dcde9fc2e19 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/equal_range2.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/equal_range2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/equal_range3.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/equal_range3.fail.cpp
index bdd1ae68140..f773c482c9f 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/equal_range3.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/equal_range3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/equal_range_transparent.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/equal_range_transparent.pass.cpp
index 4387967eb1f..44221356165 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/equal_range_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/equal_range_transparent.pass.cpp
@@ -43,7 +43,7 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::map<std::pair<int, int>, int, Comp> s{
       {{2, 1}, 1}, {{1, 2}, 2}, {{1, 3}, 3}, {{1, 4}, 4}, {{2, 2}, 5}};
 
@@ -56,4 +56,6 @@ int main() {
   }
 
   assert(nels == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/find.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/find.pass.cpp
index ca01e839c13..bcf498ecf23 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/find.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/find.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -257,4 +257,6 @@ int main()
     assert(r == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/find0.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/find0.pass.cpp
index a684738df96..affc61efb54 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/find0.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/find0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less> M;
@@ -37,4 +37,6 @@ int main()
     M example;
     assert(example.find(C2Int{5}) == example.end());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/find1.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/find1.fail.cpp
index 1cad78a398a..6bd1a95abc5 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/find1.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/find1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/find2.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/find2.fail.cpp
index cd88583160b..7af1c0eb8b2 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/find2.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/find2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/find3.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/find3.fail.cpp
index 62a4a648f70..32164fd3a97 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/find3.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/find3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/lower_bound.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/lower_bound.pass.cpp
index 3572b08f7fa..5b1c925a6c4 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/lower_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/lower_bound.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -369,4 +369,6 @@ int main()
     assert(r == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp
index 50752e8da33..a92790f2bd6 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less> M;
@@ -37,4 +37,6 @@ int main()
     M example;
     assert(example.lower_bound(C2Int{5}) == example.end());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/lower_bound1.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/lower_bound1.fail.cpp
index 095e1b3b3ed..efdc762e8b7 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/lower_bound1.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/lower_bound1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/lower_bound2.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/lower_bound2.fail.cpp
index 455e8fa9999..362b223ffa0 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/lower_bound2.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/lower_bound2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/lower_bound3.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/lower_bound3.fail.cpp
index 8c9ac1d6509..cc8bdf92af7 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/lower_bound3.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/lower_bound3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/upper_bound.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/upper_bound.pass.cpp
index 58ccd7f4343..c7fdd879a35 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/upper_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/upper_bound.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -332,4 +332,6 @@ int main()
     assert(r == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp b/libcxx/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp
index 723cdc6df6f..8f58df61b7d 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less> M;
@@ -37,4 +37,6 @@ int main()
     M example;
     assert(example.upper_bound(C2Int{5}) == example.end());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.ops/upper_bound1.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/upper_bound1.fail.cpp
index fa4afc987c9..8ed0eed59dc 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/upper_bound1.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/upper_bound1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/upper_bound2.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/upper_bound2.fail.cpp
index 5be763366c6..d08b6c0f04e 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/upper_bound2.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/upper_bound2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/map/map.ops/upper_bound3.fail.cpp b/libcxx/test/std/containers/associative/map/map.ops/upper_bound3.fail.cpp
index 773f114f9a6..df7cd226993 100644
--- a/libcxx/test/std/containers/associative/map/map.ops/upper_bound3.fail.cpp
+++ b/libcxx/test/std/containers/associative/map/map.ops/upper_bound3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/map/map.special/member_swap.pass.cpp b/libcxx/test/std/containers/associative/map/map.special/member_swap.pass.cpp
index 4f985bae3db..a41e43f7a06 100644
--- a/libcxx/test/std/containers/associative/map/map.special/member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.special/member_swap.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -172,4 +172,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.special/non_member_swap.pass.cpp b/libcxx/test/std/containers/associative/map/map.special/non_member_swap.pass.cpp
index aea80f9c3ca..811acc4573e 100644
--- a/libcxx/test/std/containers/associative/map/map.special/non_member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.special/non_member_swap.pass.cpp
@@ -20,7 +20,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -277,4 +277,6 @@ int main()
         assert(m2.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp
index 346057415b2..4e1497f7abe 100644
--- a/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp
@@ -91,7 +91,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -138,4 +138,6 @@ int main()
 #endif // _LIBCPP_VERSION
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/map/types.pass.cpp b/libcxx/test/std/containers/associative/map/types.pass.cpp
index f9f7abc28a8..35fc067433f 100644
--- a/libcxx/test/std/containers/associative/map/types.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/types.pass.cpp
@@ -33,7 +33,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::map<int, double> C;
@@ -66,4 +66,6 @@ int main()
     static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/associative/multimap/allocator_mismatch.fail.cpp
index f59df265af3..47dd64ebcaf 100644
--- a/libcxx/test/std/containers/associative/multimap/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <map>
 
-int main()
+int main(int, char**)
 {
     std::multimap<int, int, std::less<int>, std::allocator<long> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/empty.fail.cpp b/libcxx/test/std/containers/associative/multimap/empty.fail.cpp
index 91fc1026f37..bc305b9cc8d 100644
--- a/libcxx/test/std/containers/associative/multimap/empty.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::multimap<int, int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/empty.pass.cpp b/libcxx/test/std/containers/associative/multimap/empty.pass.cpp
index a83e2265cfa..12866a0f2d1 100644
--- a/libcxx/test/std/containers/associative/multimap/empty.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/empty.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double> M;
@@ -39,4 +39,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/incomplete_type.pass.cpp b/libcxx/test/std/containers/associative/multimap/incomplete_type.pass.cpp
index 5f83dce469e..0132ce9fe12 100644
--- a/libcxx/test/std/containers/associative/multimap/incomplete_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/incomplete_type.pass.cpp
@@ -23,6 +23,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 inline bool operator<(A const& L, A const& R)  { return L.data < R.data; }
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/iterator.pass.cpp b/libcxx/test/std/containers/associative/multimap/iterator.pass.cpp
index f27bce16d5c..0a61531187e 100644
--- a/libcxx/test/std/containers/associative/multimap/iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/iterator.pass.cpp
@@ -32,7 +32,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -229,4 +229,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/max_size.pass.cpp b/libcxx/test/std/containers/associative/multimap/max_size.pass.cpp
index 106bb667ca7..a4537c3d1b2 100644
--- a/libcxx/test/std/containers/associative/multimap/max_size.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   typedef std::pair<const int, int> KV;
   {
@@ -47,4 +47,6 @@ int main()
     assert(c.max_size() <= max_dist);
     assert(c.max_size() <= alloc_max_size(c.get_allocator()));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/alloc.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/alloc.pass.cpp
index e8c35d5a881..6e7e3aa0972 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::less<int> C;
@@ -46,4 +46,6 @@ int main()
     assert(m.get_allocator() == A{});
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/assign_initializer_list.pass.cpp
index 47e4e71a39f..0374062515c 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/assign_initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double> C;
@@ -79,4 +79,6 @@ int main()
     assert(*++i == V(3, 1.5));
     assert(*++i == V(3, 2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/compare.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/compare.pass.cpp
index 5b83bb0be1c..54bf998ecdd 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/compare.pass.cpp
@@ -20,7 +20,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > C;
@@ -38,4 +38,6 @@ int main()
     assert(m.key_comp() == C(3));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_alloc.pass.cpp
index 1f11066f86e..44942036c73 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > C;
@@ -50,4 +50,6 @@ int main()
     assert(m.get_allocator() == A{});
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_copy_constructible.fail.cpp
index 19276a0eef2..23fe479f56c 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/compare_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::multimap<int, int, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/copy.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/copy.pass.cpp
index c691a196535..d3b06425677 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/copy.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -99,4 +99,6 @@ int main()
         assert(mo.key_comp() == C(5));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_alloc.pass.cpp
index 3c549d6aed1..7144a25f9d4 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -98,4 +98,6 @@ int main()
     assert(mo.key_comp() == C(5));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_assign.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_assign.pass.cpp
index d4929086813..6816a5ee43f 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/copy_assign.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<const int, double> V;
@@ -121,4 +121,6 @@ int main()
         assert(mo.key_comp() == C(5));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/default.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/default.pass.cpp
index 6c59b603bdf..6b33088434d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/default.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::multimap<int, double> m;
@@ -50,4 +50,6 @@ int main()
     assert(m.begin() == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/default_noexcept.pass.cpp
index d55adedc906..e5a28601eec 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/default_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
 #if defined(_LIBCPP_VERSION)
@@ -54,4 +54,6 @@ int main()
         typedef std::multimap<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp
index 8d960dbe32d..b51b6b63b7d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp
@@ -23,6 +23,8 @@ struct X
     std::multimap<int, X>::const_reverse_iterator cri;
 };
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/dtor_noexcept.pass.cpp
index 01cdff8c310..100746789ac 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -48,4 +48,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list.pass.cpp
index bd26b397c5d..2642ba6a8ee 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double> C;
@@ -77,4 +77,6 @@ int main()
     assert(*++i == V(3, 1.5));
     assert(*++i == V(3, 2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare.pass.cpp
index a3f29e60794..c8e2d293fa0 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > Cmp;
@@ -85,4 +85,6 @@ int main()
     assert(*++i == V(3, 2));
     assert(m.key_comp() == Cmp(4));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare_alloc.pass.cpp
index 572a3cfb0b6..592dec99749 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/initializer_list_compare_alloc.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > Cmp;
@@ -155,4 +155,6 @@ int main()
     assert(m.key_comp() == Cmp(4));
     assert(m.get_allocator() == A{});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter.pass.cpp
index 0ea352404d1..4d92b3d0b7d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -109,4 +109,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp.pass.cpp
index aa114a25a6e..d10904a4d44 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp.pass.cpp
@@ -20,7 +20,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -82,4 +82,6 @@ int main()
     assert(*next(m.begin(), 8) == V(3, 2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp_alloc.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp_alloc.pass.cpp
index 7d02c753935..a71c757ffd7 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/iter_iter_comp_alloc.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<const int, double> V;
@@ -118,4 +118,6 @@ int main()
     assert(*next(m.begin(), 8) == V(3, 2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/move.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/move.pass.cpp
index 324e0a140c5..cef6857740c 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/move.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -126,4 +126,6 @@ int main()
         assert(mo.size() == 0);
         assert(distance(mo.begin(), mo.end()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_alloc.pass.cpp
index 3342a4edaab..712afbeaa6a 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_alloc.pass.cpp
@@ -24,7 +24,7 @@
 #include "min_allocator.h"
 #include "Counter.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<MoveOnly, MoveOnly> V;
@@ -268,4 +268,6 @@ int main()
         assert(m3.key_comp() == C(5));
         LIBCPP_ASSERT(m1.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign.pass.cpp
index c1f8e7e5a64..386c11ecba2 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<MoveOnly, MoveOnly> V;
@@ -184,4 +184,6 @@ int main()
         assert(m3.key_comp() == C(5));
         assert(m1.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign_noexcept.pass.cpp
index 41ea6585330..2afcc5e58f8 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_assign_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -54,4 +54,6 @@ int main()
         typedef std::multimap<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_noexcept.pass.cpp
index b1c148a9fac..37716748420 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/move_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     typedef std::pair<const MoveOnly, MoveOnly> V;
@@ -52,4 +52,6 @@ int main()
         typedef std::multimap<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.erasure/erase_if.pass.cpp
index dc448f58d9d..15893f77b63 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.erasure/erase_if.pass.cpp
@@ -77,7 +77,7 @@ void test()
     test0<S>({1,2,3}, False, {1,2,3});
 }
 
-int main()
+int main(int, char**)
 {
     test<std::multimap<int, int>>();
     test<std::multimap<int, int, std::less<int>, min_allocator<std::pair<const int, int>>>> ();
@@ -85,4 +85,6 @@ int main()
 
     test<std::multimap<long, short>>();
     test<std::multimap<short, double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/clear.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/clear.pass.cpp
index 0cb5cb29b42..d05a13b5f19 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/clear.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, double> M;
@@ -62,4 +62,6 @@ int main()
         assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace.pass.cpp
index 2780d3a5320..76d9b171832 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, DefaultOnly> M;
@@ -144,4 +144,6 @@ int main()
         assert(m.begin()->first == 2);
         assert(m.begin()->second == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace_hint.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace_hint.pass.cpp
index 49ee3069b28..3ad09f38a70 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/emplace_hint.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, DefaultOnly> M;
@@ -154,4 +154,6 @@ int main()
         assert(m.begin()->first == 2);
         assert(m.begin()->second == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter.pass.cpp
index 62ab3f5fd31..a0f70d640bd 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter.pass.cpp
@@ -25,7 +25,7 @@ struct TemplateConstructor
 
 bool operator<(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, double> M;
@@ -297,4 +297,6 @@ int main()
             c.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter_iter.pass.cpp
index f561d149b53..deef1a1461d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_iter_iter.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, double> M;
@@ -153,4 +153,6 @@ int main()
         assert(i == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_key.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_key.pass.cpp
index f881c77c27a..0ab1d4cb8ab 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/erase_key.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, double> M;
@@ -149,4 +149,6 @@ int main()
         assert(i == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_iterator.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_iterator.pass.cpp
index a0992d75157..fe3c7883244 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_iterator.pass.cpp
@@ -40,7 +40,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using map_type = std::multimap<int, int>;
@@ -63,4 +63,6 @@ int main()
         min_alloc_map m = {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {5, 5}, {6, 6}};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_key.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_key.pass.cpp
index 687043a4cc5..e2a80dab25f 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/extract_key.pass.cpp
@@ -45,7 +45,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::multimap<int, int> m = {{1,1}, {2,2}, {3,3}, {4,4}, {5,5}, {6,6}};
@@ -72,4 +72,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_allocator_requirements.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_allocator_requirements.pass.cpp
index 008770cbfdd..9a791af57e6 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_allocator_requirements.pass.cpp
@@ -20,8 +20,10 @@
 #include "../../../map_allocator_requirement_test_templates.h"
 
 
-int main()
+int main(int, char**)
 {
   testMultimapInsert<TCT::multimap<> >();
   testMultimapInsertHint<TCT::multimap<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_cv.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_cv.pass.cpp
index 8c4e51b2481..b83034448a1 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_cv.pass.cpp
@@ -53,7 +53,7 @@ void do_insert_test() {
     assert(r->second == 3.5);
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, double> Container;
@@ -65,4 +65,6 @@ int main()
         do_insert_test<Container>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_initializer_list.pass.cpp
index 2da3e7d4941..33104ca88b5 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double> C;
@@ -85,4 +85,6 @@ int main()
     assert(*++i == V(3, 2));
     assert(*++i == V(3, 1.5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_cv.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_cv.pass.cpp
index 946193446b5..fb3283f8384 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_cv.pass.cpp
@@ -54,7 +54,7 @@ void do_insert_hint_test()
     assert(r->second == 4.5);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_hint_test<std::multimap<int, double> >();
 #if TEST_STD_VER >= 11
@@ -63,4 +63,6 @@ int main()
         do_insert_hint_test<M>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_iter.pass.cpp
index f7a11f86c4f..9533a62896d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multimap<int, double> M;
@@ -97,4 +97,6 @@ int main()
         assert(next(m.begin(), 8)->second == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_rv.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_rv.pass.cpp
index 0912136f180..5eea856a0d8 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_iter_rv.pass.cpp
@@ -54,7 +54,7 @@ void do_insert_rv_test()
     assert(r->second == 2);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_rv_test<std::multimap<int, MoveOnly>, std::pair<int, MoveOnly> >();
     do_insert_rv_test<std::multimap<int, MoveOnly>, std::pair<const int, MoveOnly> >();
@@ -95,4 +95,6 @@ int main()
         assert(r->first == 3);
         assert(r->second == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type.pass.cpp
index 71122d3a39a..7fb62a7c16e 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type.pass.cpp
@@ -68,10 +68,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::multimap<int, int> m;
     test(m);
     std::multimap<int, int, std::less<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type_hint.pass.cpp
index edc7d2bd326..847a7013692 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_node_type_hint.pass.cpp
@@ -54,10 +54,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::multimap<int, int> m;
     test(m);
     std::multimap<int, int, std::less<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_rv.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_rv.pass.cpp
index 041ce97a63d..05393345c12 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_rv.pass.cpp
@@ -54,7 +54,7 @@ void do_insert_rv_test()
     assert(r->second == 3);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_rv_test<std::multimap<int, MoveOnly>>();
     {
@@ -89,4 +89,6 @@ int main()
         assert(r->first == 3);
         assert(r->second == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/merge.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/merge.pass.cpp
index 449d5d92dda..78b24323d44 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.modifiers/merge.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.modifiers/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_comparator
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::multimap<int, int> src{{1, 0}, {3, 0}, {5, 0}};
@@ -146,4 +146,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/count.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/count.pass.cpp
index 7bdb4d20070..053a771bae3 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/count.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/count.pass.cpp
@@ -20,7 +20,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -172,4 +172,6 @@ int main()
     assert(r == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp
index f725d16f8b3..75f9f222816 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less> M;
@@ -35,4 +35,6 @@ int main()
     typedef std::multimap<int, double, transparent_less_not_referenceable> M;
     assert(M().count(C2Int{5}) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/count1.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/count1.fail.cpp
index 28842553b5f..594a424fad4 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/count1.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/count1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     typedef std::multimap<int, double, transparent_less_no_type> M;
 
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/count2.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/count2.fail.cpp
index 5f06d322618..1f98052b7b2 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/count2.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/count2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     typedef std::multimap<int, double, transparent_less_private> M;
 
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/count3.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/count3.fail.cpp
index 2f3aa4dcbf9..3304d9f0640 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/count3.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/count3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     typedef std::multimap<int, double, transparent_less_not_a_type> M;
 
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/count_transparent.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/count_transparent.pass.cpp
index 0483276f84b..e6348cbef2a 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/count_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/count_transparent.pass.cpp
@@ -40,10 +40,12 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::multimap<std::pair<int, int>, int, Comp> s{
       {{2, 1}, 1}, {{1, 1}, 2}, {{1, 1}, 3}, {{1, 1}, 4}, {{2, 2}, 5}};
 
   auto cnt = s.count(1);
   assert(cnt == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range.pass.cpp
index 47380d881ca..3d4997f4844 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -283,4 +283,6 @@ int main()
     assert(r.second == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp
index 48002b38123..c01395f0a41 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less> M;
@@ -41,4 +41,6 @@ int main()
     P result = example.equal_range(C2Int{5});
     assert(result.first == result.second);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range1.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range1.fail.cpp
index ea7941c71f6..b826f018fae 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range1.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     typedef std::multimap<int, double, transparent_less_no_type> M;
 
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range2.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range2.fail.cpp
index a6fc925a807..a533a7144e7 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range2.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range3.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range3.fail.cpp
index 8b5e77242df..2a26a5849c9 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range3.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range_transparent.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range_transparent.pass.cpp
index 34326a453b1..95af97cee52 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/equal_range_transparent.pass.cpp
@@ -43,7 +43,7 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::multimap<std::pair<int, int>, int, Comp> s{
       {{2, 1}, 1}, {{1, 1}, 2}, {{1, 1}, 3}, {{1, 1}, 4}, {{2, 2}, 5}};
 
@@ -56,4 +56,6 @@ int main() {
   }
 
   assert(nels == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/find.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/find.pass.cpp
index 006f98b9635..e526d9a3270 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/find.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/find.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -219,4 +219,6 @@ int main()
     assert(r == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp
index 2516b16e7e5..39a8735bccb 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less> M;
@@ -37,4 +37,6 @@ int main()
     M example;
     assert(example.find(C2Int{5}) == example.end());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/find1.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/find1.fail.cpp
index 754df859a8a..a22d1b5a037 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/find1.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/find1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/find2.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/find2.fail.cpp
index 898fdbafbbf..cf2e4b4987b 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/find2.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/find2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/find3.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/find3.fail.cpp
index 68608e8d049..2be4062bb5d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/find3.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/find3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound.pass.cpp
index c94f99d4940..77550b5186a 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -233,4 +233,6 @@ int main()
     }
 
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp
index fd604d14ebc..1311c9c5a47 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less> M;
@@ -37,4 +37,6 @@ int main()
     M example;
     assert(example.lower_bound(C2Int{5}) == example.end());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound1.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound1.fail.cpp
index 510421a8abd..0279f54bf44 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound1.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound2.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound2.fail.cpp
index afcf3285ad5..2282003f4d4 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound2.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound3.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound3.fail.cpp
index 3c7e276763e..f5751647ac6 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound3.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/lower_bound3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound.pass.cpp
index 5a0d7c3ce43..762387d800d 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound.pass.cpp
@@ -21,7 +21,7 @@
 #include "private_constructor.hpp"
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -232,4 +232,6 @@ int main()
     }
 
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp
index 5f257ece9f9..28c9ff75a75 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "is_transparent.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less> M;
@@ -37,4 +37,6 @@ int main()
     M example;
     assert(example.upper_bound(C2Int{5}) == example.end());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound1.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound1.fail.cpp
index 33775d23872..39ecc3cc4cf 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound1.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound1.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_no_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound2.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound2.fail.cpp
index c2be3e7ebe5..f51a199c119 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound2.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound2.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_private> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound3.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound3.fail.cpp
index 5c1d2a77bf1..68d05710048 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound3.fail.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.ops/upper_bound3.fail.cpp
@@ -28,7 +28,7 @@
 #error "This test requires is C++14 (or later)"
 #else
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double, transparent_less_not_a_type> M;
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.special/member_swap.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.special/member_swap.pass.cpp
index 09740b3f331..fe8399713ef 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.special/member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.special/member_swap.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -172,4 +172,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.special/non_member_swap.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.special/non_member_swap.pass.cpp
index b776766dda6..3e75991ee95 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.special/non_member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.special/non_member_swap.pass.cpp
@@ -20,7 +20,7 @@
 #include "../../../test_compare.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const int, double> V;
     {
@@ -277,4 +277,6 @@ int main()
         assert(m2.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp
index 7c42ff170d8..9d5dab06c89 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp
@@ -91,7 +91,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -137,4 +137,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/scary.pass.cpp b/libcxx/test/std/containers/associative/multimap/scary.pass.cpp
index 2032bfc9699..faf839b8ee1 100644
--- a/libcxx/test/std/containers/associative/multimap/scary.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/scary.pass.cpp
@@ -14,11 +14,13 @@
 
 #include <map>
 
-int main()
+int main(int, char**)
 {
     typedef std::map<int, int> M1;
     typedef std::multimap<int, int> M2;
     M2::iterator i;
     M1::iterator j = i;
     ((void)j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/size.pass.cpp b/libcxx/test/std/containers/associative/multimap/size.pass.cpp
index b608b99e93c..df18f7b58cc 100644
--- a/libcxx/test/std/containers/associative/multimap/size.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/size.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double> M;
@@ -55,4 +55,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multimap/types.pass.cpp b/libcxx/test/std/containers/associative/multimap/types.pass.cpp
index 7c91ab3bdad..67723f5cdc4 100644
--- a/libcxx/test/std/containers/associative/multimap/types.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/types.pass.cpp
@@ -33,7 +33,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multimap<int, double> C;
@@ -66,4 +66,6 @@ int main()
     static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/associative/multiset/allocator_mismatch.fail.cpp
index ffa0e964074..86e1b307a3d 100644
--- a/libcxx/test/std/containers/associative/multiset/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/associative/multiset/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <set>
 
-int main()
+int main(int, char**)
 {
     std::multiset<int, std::less<int>, std::allocator<long> > ms;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/clear.pass.cpp b/libcxx/test/std/containers/associative/multiset/clear.pass.cpp
index b5ad9e4f304..93f9fef2caa 100644
--- a/libcxx/test/std/containers/associative/multiset/clear.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/clear.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<int> M;
@@ -62,4 +62,6 @@ int main()
         assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/count.pass.cpp b/libcxx/test/std/containers/associative/multiset/count.pass.cpp
index 61d64adb6ae..3ac6f942304 100644
--- a/libcxx/test/std/containers/associative/multiset/count.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/count.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -157,4 +157,6 @@ int main()
     assert(r == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/count_transparent.pass.cpp b/libcxx/test/std/containers/associative/multiset/count_transparent.pass.cpp
index e26744a75f2..1239286f76c 100644
--- a/libcxx/test/std/containers/associative/multiset/count_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/count_transparent.pass.cpp
@@ -42,9 +42,11 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::multiset<std::pair<int, int>, Comp> s{{2, 1}, {1, 1}, {1, 1}, {1, 1}, {2, 2}};
 
   auto cnt = s.count(1);
   assert(cnt == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/emplace.pass.cpp b/libcxx/test/std/containers/associative/multiset/emplace.pass.cpp
index 8e7b6946c35..1cabd12fce0 100644
--- a/libcxx/test/std/containers/associative/multiset/emplace.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/emplace.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<DefaultOnly> M;
@@ -77,4 +77,6 @@ int main()
         assert(m.size() == 1);
         assert(*r == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/emplace_hint.pass.cpp b/libcxx/test/std/containers/associative/multiset/emplace_hint.pass.cpp
index d8723d8d916..17db3b4b366 100644
--- a/libcxx/test/std/containers/associative/multiset/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/emplace_hint.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<DefaultOnly> M;
@@ -77,4 +77,6 @@ int main()
         assert(m.size() == 1);
         assert(*r == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/empty.fail.cpp b/libcxx/test/std/containers/associative/multiset/empty.fail.cpp
index 29c31a0899a..4467b487089 100644
--- a/libcxx/test/std/containers/associative/multiset/empty.fail.cpp
+++ b/libcxx/test/std/containers/associative/multiset/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::multiset<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/empty.pass.cpp b/libcxx/test/std/containers/associative/multiset/empty.pass.cpp
index f0591d8e3d9..2ca20491fca 100644
--- a/libcxx/test/std/containers/associative/multiset/empty.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/empty.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multiset<int> M;
@@ -39,4 +39,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/equal_range.pass.cpp b/libcxx/test/std/containers/associative/multiset/equal_range.pass.cpp
index 740ecc7f290..44c6c17ecce 100644
--- a/libcxx/test/std/containers/associative/multiset/equal_range.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/equal_range.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -260,4 +260,6 @@ int main()
     assert(r.second == next(m.begin(), 9));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/equal_range_transparent.pass.cpp b/libcxx/test/std/containers/associative/multiset/equal_range_transparent.pass.cpp
index 075aab1a365..d052cf169b7 100644
--- a/libcxx/test/std/containers/associative/multiset/equal_range_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/equal_range_transparent.pass.cpp
@@ -44,7 +44,7 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::multiset<std::pair<int, int>, Comp> s{{2, 1}, {1, 1}, {1, 1}, {1, 1}, {2, 2}};
 
   auto er = s.equal_range(1);
@@ -56,4 +56,6 @@ int main() {
   }
 
   assert(nels == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/erase_iter.pass.cpp b/libcxx/test/std/containers/associative/multiset/erase_iter.pass.cpp
index 506a0a7c2f9..bcedbf338a6 100644
--- a/libcxx/test/std/containers/associative/multiset/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/erase_iter.pass.cpp
@@ -25,7 +25,7 @@ struct TemplateConstructor
 
 bool operator<(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<int> M;
@@ -199,4 +199,6 @@ int main()
             c.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/multiset/erase_iter_iter.pass.cpp
index b1e2d143b72..03c72528594 100644
--- a/libcxx/test/std/containers/associative/multiset/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/erase_iter_iter.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<int> M;
@@ -137,4 +137,6 @@ int main()
         assert(i == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/erase_key.pass.cpp b/libcxx/test/std/containers/associative/multiset/erase_key.pass.cpp
index d2c3d17db32..4b1db052960 100644
--- a/libcxx/test/std/containers/associative/multiset/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/erase_key.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<int> M;
@@ -125,4 +125,6 @@ int main()
         assert(i == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/extract_iterator.pass.cpp b/libcxx/test/std/containers/associative/multiset/extract_iterator.pass.cpp
index f162081902f..ef2a64eded0 100644
--- a/libcxx/test/std/containers/associative/multiset/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/extract_iterator.pass.cpp
@@ -36,7 +36,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using set_type = std::multiset<int>;
@@ -56,4 +56,6 @@ int main()
         min_alloc_set m = {1, 2, 3, 4, 5, 6};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/extract_key.pass.cpp b/libcxx/test/std/containers/associative/multiset/extract_key.pass.cpp
index 7fc0459cae0..d95667def3a 100644
--- a/libcxx/test/std/containers/associative/multiset/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/extract_key.pass.cpp
@@ -43,7 +43,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::multiset<int> m = {1, 2, 3, 4, 5, 6};
@@ -67,4 +67,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/find.pass.cpp b/libcxx/test/std/containers/associative/multiset/find.pass.cpp
index 44d8d051cfc..7a6584b2bb1 100644
--- a/libcxx/test/std/containers/associative/multiset/find.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/find.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -237,4 +237,6 @@ int main()
     assert(r == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/incomplete_type.pass.cpp b/libcxx/test/std/containers/associative/multiset/incomplete_type.pass.cpp
index 71166b2ecd3..a118a6230eb 100644
--- a/libcxx/test/std/containers/associative/multiset/incomplete_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/incomplete_type.pass.cpp
@@ -23,6 +23,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 inline bool operator<(A const& L, A const& R)  { return L.data < R.data; }
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_cv.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_cv.pass.cpp
index 21fec2cd95b..856d54da0d4 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_cv.pass.cpp
@@ -48,7 +48,7 @@ void do_insert_cv_test()
     assert(*r == 3);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_cv_test<std::multiset<int> >();
 #if TEST_STD_VER >= 11
@@ -57,4 +57,6 @@ int main()
         do_insert_cv_test<M>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_emplace_allocator_requirements.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_emplace_allocator_requirements.pass.cpp
index 6b6c22f2851..083dea73917 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_emplace_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_emplace_allocator_requirements.pass.cpp
@@ -19,8 +19,10 @@
 #include "container_test_types.h"
 #include "../../set_allocator_requirement_test_templates.h"
 
-int main()
+int main(int, char**)
 {
   testMultisetInsert<TCT::multiset<> >();
   testMultisetEmplace<TCT::multiset<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_initializer_list.pass.cpp
index 29a746696b6..7f7a00c15f8 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_initializer_list.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multiset<int> C;
@@ -56,4 +56,6 @@ int main()
     assert(*++i == V(8));
     assert(*++i == V(10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_iter_cv.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_iter_cv.pass.cpp
index b0da5f4f2d7..e29e7b484eb 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_iter_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_iter_cv.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<int> M;
@@ -69,4 +69,6 @@ int main()
         assert(*r == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_iter_iter.pass.cpp
index 07b8000d941..242b9d7f6cc 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<int> M;
@@ -81,4 +81,6 @@ int main()
         assert(*next(m.begin(), 8) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_iter_rv.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_iter_rv.pass.cpp
index 3dea1f8a222..e905c5c4072 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_iter_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_iter_rv.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<MoveOnly> M;
@@ -70,4 +70,6 @@ int main()
         assert(m.size() == 4);
         assert(*r == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_node_type.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_node_type.pass.cpp
index b8aad6c8cc6..7cf2cebfb58 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_node_type.pass.cpp
@@ -67,10 +67,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::multiset<int> m;
     test(m);
     std::multiset<int, std::less<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_node_type_hint.pass.cpp
index 3e5b40b96c5..d4d6871fb13 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_node_type_hint.pass.cpp
@@ -49,10 +49,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::multiset<int> m;
     test(m);
     std::multiset<int, std::less<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/insert_rv.pass.cpp b/libcxx/test/std/containers/associative/multiset/insert_rv.pass.cpp
index 9d50c617dc9..3f73a2813b0 100644
--- a/libcxx/test/std/containers/associative/multiset/insert_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/insert_rv.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<MoveOnly> M;
@@ -70,4 +70,6 @@ int main()
         assert(m.size() == 4);
         assert(*r == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/iterator.pass.cpp b/libcxx/test/std/containers/associative/multiset/iterator.pass.cpp
index bda2c7faa82..4ab1d79a049 100644
--- a/libcxx/test/std/containers/associative/multiset/iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/iterator.pass.cpp
@@ -32,7 +32,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -213,4 +213,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/lower_bound.pass.cpp b/libcxx/test/std/containers/associative/multiset/lower_bound.pass.cpp
index dd9fdf70c7a..6d31f04c8ee 100644
--- a/libcxx/test/std/containers/associative/multiset/lower_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/lower_bound.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -220,4 +220,6 @@ int main()
     assert(r == next(m.begin(), 9));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/max_size.pass.cpp b/libcxx/test/std/containers/associative/multiset/max_size.pass.cpp
index 64baa6cb046..5986df29554 100644
--- a/libcxx/test/std/containers/associative/multiset/max_size.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
       typedef limited_allocator<int, 10> A;
@@ -46,4 +46,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/merge.pass.cpp b/libcxx/test/std/containers/associative/multiset/merge.pass.cpp
index 9d566484c33..e7e05b155f4 100644
--- a/libcxx/test/std/containers/associative/multiset/merge.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_comparator
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::multiset<int> src{1, 3, 5};
@@ -145,4 +145,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/alloc.pass.cpp
index 4debe7b4278..9ceac884b64 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/alloc.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::less<int> C;
     typedef test_allocator<int> A;
@@ -25,4 +25,6 @@ int main()
     assert(m.empty());
     assert(m.begin() == m.end());
     assert(m.get_allocator() == A(5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/assign_initializer_list.pass.cpp
index f325fe919d4..c84b042930a 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/assign_initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multiset<int> C;
@@ -51,4 +51,6 @@ int main()
     assert(*++i == V(5));
     assert(*++i == V(6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/compare.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/compare.pass.cpp
index b628d50ff86..d35de106f85 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/compare.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > C;
     const std::multiset<int, C> m(C(3));
@@ -29,4 +29,6 @@ int main()
     assert(m.begin() == m.end());
     assert(m.key_comp() == C(3));
     assert(m.value_comp() == C(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_alloc.pass.cpp
index e06c21719b3..f044b2790b9 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > C;
     typedef test_allocator<int> A;
@@ -27,4 +27,6 @@ int main()
     assert(m.begin() == m.end());
     assert(m.key_comp() == C(4));
     assert(m.get_allocator() == A(5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_copy_constructible.fail.cpp
index 09c2ac0936c..ae987c64c85 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/compare_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::multiset<int, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/copy.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/copy.pass.cpp
index a055b15fce1..ac196b5ae33 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/copy.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -115,4 +115,6 @@ int main()
         assert(*next(mo.begin(), 8) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_alloc.pass.cpp
index 4466438ca1e..25e6d6efb2d 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef int V;
     V ar[] =
@@ -64,4 +64,6 @@ int main()
     assert(*next(mo.begin(), 6) == 3);
     assert(*next(mo.begin(), 7) == 3);
     assert(*next(mo.begin(), 8) == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_assign.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_assign.pass.cpp
index 0efa8bec69a..7992c7cae95 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/copy_assign.pass.cpp
@@ -18,7 +18,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -134,4 +134,6 @@ int main()
         assert(*next(mo.begin(), 7) == 3);
         assert(*next(mo.begin(), 8) == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/default.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/default.pass.cpp
index a84bc6d10e2..88c5244f8f9 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/default.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::multiset<int> m;
@@ -50,4 +50,6 @@ int main()
     assert(m.begin() == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/default_noexcept.pass.cpp
index 747e948ed89..7fa25ac4786 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/default_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -53,4 +53,6 @@ int main()
         typedef std::multiset<MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/dtor_noexcept.pass.cpp
index e268282651f..8a18a2977de 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list.pass.cpp
index c0a682e91a1..68a74e80cdc 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multiset<int> C;
@@ -66,4 +66,6 @@ int main()
     assert(*++i == V(6));
     assert(m.get_allocator() == a);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare.pass.cpp
index 719476c7d17..cf4c11dcfb6 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > Cmp;
     typedef std::multiset<int, Cmp> C;
@@ -34,4 +34,6 @@ int main()
     assert(*++i == V(5));
     assert(*++i == V(6));
     assert(m.key_comp() == Cmp(10));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare_alloc.pass.cpp
index 61a1f3ca0ff..5f26864cd21 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/initializer_list_compare_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > Cmp;
     typedef test_allocator<int> A;
@@ -37,4 +37,6 @@ int main()
     assert(*++i == V(6));
     assert(m.key_comp() == Cmp(10));
     assert(m.get_allocator() == A(4));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter.pass.cpp
index a1806ecf9c3..9d521c27905 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -79,4 +79,6 @@ int main()
     assert(*next(m.begin(), 8) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_alloc.pass.cpp
index 3a37ac014ea..82d9f4aea1c 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_alloc.pass.cpp
@@ -22,7 +22,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -91,4 +91,6 @@ int main()
     assert(m.get_allocator() == a);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_comp.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_comp.pass.cpp
index 77f6b10c4b5..25b4364c182 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_comp.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/iter_iter_comp.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef int V;
     V ar[] =
@@ -49,4 +49,6 @@ int main()
     assert(*next(m.begin(), 6) == 3);
     assert(*next(m.begin(), 7) == 3);
     assert(*next(m.begin(), 8) == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/move.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/move.pass.cpp
index 8d43c098ef0..0d6cc72a66e 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/move.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -113,4 +113,6 @@ int main()
         assert(mo.size() == 0);
         assert(distance(mo.begin(), mo.end()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp
index c91a97b490f..1abe5b928b5 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_allocator.h"
 #include "Counter.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly V;
@@ -184,4 +184,6 @@ int main()
         }
         assert(Counter_base::gConstructed == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign.pass.cpp
index 263e48b46fc..6f584f22cf8 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly V;
@@ -180,4 +180,6 @@ int main()
         assert(m3.key_comp() == C(5));
         assert(m1.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign_noexcept.pass.cpp
index aa164edf0c1..026fc1ba7f1 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_assign_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<MoveOnly> C;
@@ -53,4 +53,6 @@ int main()
         typedef std::multiset<MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_noexcept.pass.cpp
index 41fd86269bc..88bbb59a43d 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -51,4 +51,6 @@ int main()
         typedef std::multiset<MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.erasure/erase_if.pass.cpp
index 19a0d131f87..84d665cb151 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.erasure/erase_if.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,3}), False, S({1,2,3}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::multiset<int>>();
     test<std::multiset<int, std::less<int>, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::multiset<long>>();
     test<std::multiset<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.special/member_swap.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.special/member_swap.pass.cpp
index be113250225..9ac0f1709e9 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.special/member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.special/member_swap.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -173,4 +173,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.special/non_member_swap.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.special/non_member_swap.pass.cpp
index 9b6d021f5bc..a3bbf551d3d 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.special/non_member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.special/non_member_swap.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef int V;
     {
@@ -163,4 +163,6 @@ int main()
         assert(m2.key_comp() == C(1));
         assert(m2.get_allocator() == A(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp
index 367e6e1c942..47a0d411f93 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp
@@ -91,7 +91,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::multiset<MoveOnly> C;
@@ -136,4 +136,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/scary.pass.cpp b/libcxx/test/std/containers/associative/multiset/scary.pass.cpp
index 329f9f18fd1..5065ab96eaa 100644
--- a/libcxx/test/std/containers/associative/multiset/scary.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/scary.pass.cpp
@@ -14,11 +14,13 @@
 
 #include <set>
 
-int main()
+int main(int, char**)
 {
     typedef std::set<int> M1;
     typedef std::multiset<int> M2;
     M2::iterator i;
     M1::iterator j = i;
     ((void)j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/size.pass.cpp b/libcxx/test/std/containers/associative/multiset/size.pass.cpp
index ccb3f0f7a7d..bb5616e9a62 100644
--- a/libcxx/test/std/containers/associative/multiset/size.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/size.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multiset<int> M;
@@ -55,4 +55,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/types.pass.cpp b/libcxx/test/std/containers/associative/multiset/types.pass.cpp
index 3ee2fc57087..96e8ec4f0b1 100644
--- a/libcxx/test/std/containers/associative/multiset/types.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/types.pass.cpp
@@ -33,7 +33,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::multiset<int> C;
@@ -66,4 +66,6 @@ int main()
     static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/multiset/upper_bound.pass.cpp b/libcxx/test/std/containers/associative/multiset/upper_bound.pass.cpp
index f2796d7b432..99a7e374d12 100644
--- a/libcxx/test/std/containers/associative/multiset/upper_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/upper_bound.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -219,4 +219,6 @@ int main()
     assert(r == next(m.begin(), 9));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/associative/set/allocator_mismatch.fail.cpp
index ed36019680a..69e49351e20 100644
--- a/libcxx/test/std/containers/associative/set/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/associative/set/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <set>
 
-int main()
+int main(int, char**)
 {
     std::set<int, std::less<int>, std::allocator<long> > s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/clear.pass.cpp b/libcxx/test/std/containers/associative/set/clear.pass.cpp
index 3f84ee480cb..0650e912fd3 100644
--- a/libcxx/test/std/containers/associative/set/clear.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/clear.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<int> M;
@@ -62,4 +62,6 @@ int main()
         assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/count.pass.cpp b/libcxx/test/std/containers/associative/set/count.pass.cpp
index e915b1cde80..8866aa7f057 100644
--- a/libcxx/test/std/containers/associative/set/count.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/count.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -167,4 +167,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/count_transparent.pass.cpp b/libcxx/test/std/containers/associative/set/count_transparent.pass.cpp
index e8490e6de08..d94188def08 100644
--- a/libcxx/test/std/containers/associative/set/count_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/count_transparent.pass.cpp
@@ -42,9 +42,11 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::set<std::pair<int, int>, Comp> s{{2, 1}, {1, 2}, {1, 3}, {1, 4}, {2, 2}};
 
   auto cnt = s.count(1);
   assert(cnt == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/emplace.pass.cpp b/libcxx/test/std/containers/associative/set/emplace.pass.cpp
index fdabf02a81d..e48f2e1e447 100644
--- a/libcxx/test/std/containers/associative/set/emplace.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/emplace.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<DefaultOnly> M;
@@ -84,4 +84,6 @@ int main()
         assert(m.size() == 1);
         assert(*r.first == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/emplace_hint.pass.cpp b/libcxx/test/std/containers/associative/set/emplace_hint.pass.cpp
index 441adaf2125..a7ed7266be2 100644
--- a/libcxx/test/std/containers/associative/set/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/emplace_hint.pass.cpp
@@ -22,7 +22,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<DefaultOnly> M;
@@ -77,4 +77,6 @@ int main()
         assert(m.size() == 1);
         assert(*r == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/empty.fail.cpp b/libcxx/test/std/containers/associative/set/empty.fail.cpp
index 7954f6f496b..fc5856fbdbf 100644
--- a/libcxx/test/std/containers/associative/set/empty.fail.cpp
+++ b/libcxx/test/std/containers/associative/set/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::set<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/empty.pass.cpp b/libcxx/test/std/containers/associative/set/empty.pass.cpp
index 50ce5dd3bf7..c00ab68ffc9 100644
--- a/libcxx/test/std/containers/associative/set/empty.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/empty.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::set<int> M;
@@ -39,4 +39,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/equal_range.pass.cpp b/libcxx/test/std/containers/associative/set/equal_range.pass.cpp
index da221aa54ad..5c43706118d 100644
--- a/libcxx/test/std/containers/associative/set/equal_range.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/equal_range.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -367,4 +367,6 @@ int main()
     assert(r.second == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/equal_range_transparent.pass.cpp b/libcxx/test/std/containers/associative/set/equal_range_transparent.pass.cpp
index c091aa6b5d8..b69ff2d522f 100644
--- a/libcxx/test/std/containers/associative/set/equal_range_transparent.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/equal_range_transparent.pass.cpp
@@ -44,7 +44,7 @@ struct Comp {
   }
 };
 
-int main() {
+int main(int, char**) {
   std::set<std::pair<int, int>, Comp> s{{2, 1}, {1, 2}, {1, 3}, {1, 4}, {2, 2}};
 
   auto er = s.equal_range(1);
@@ -56,4 +56,6 @@ int main() {
   }
 
   assert(nels == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/erase_iter.pass.cpp b/libcxx/test/std/containers/associative/set/erase_iter.pass.cpp
index 99650d3d03f..49ce4f29e77 100644
--- a/libcxx/test/std/containers/associative/set/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/erase_iter.pass.cpp
@@ -25,7 +25,7 @@ struct TemplateConstructor
 
 bool operator<(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<int> M;
@@ -199,4 +199,6 @@ int main()
             c.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/set/erase_iter_iter.pass.cpp
index b98d83ad8a1..86fd52c2cb4 100644
--- a/libcxx/test/std/containers/associative/set/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/erase_iter_iter.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<int> M;
@@ -137,4 +137,6 @@ int main()
         assert(i == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/erase_key.pass.cpp b/libcxx/test/std/containers/associative/set/erase_key.pass.cpp
index da3ea5c14d8..3ceec88500b 100644
--- a/libcxx/test/std/containers/associative/set/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/erase_key.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<int> M;
@@ -199,4 +199,6 @@ int main()
         assert(i == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/extract_iterator.pass.cpp b/libcxx/test/std/containers/associative/set/extract_iterator.pass.cpp
index da95331f7c7..1ba13e318a6 100644
--- a/libcxx/test/std/containers/associative/set/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/extract_iterator.pass.cpp
@@ -36,7 +36,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using set_type = std::set<int>;
@@ -56,4 +56,6 @@ int main()
         min_alloc_set m = {1, 2, 3, 4, 5, 6};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/extract_key.pass.cpp b/libcxx/test/std/containers/associative/set/extract_key.pass.cpp
index 68f24f65449..4417e86367b 100644
--- a/libcxx/test/std/containers/associative/set/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/extract_key.pass.cpp
@@ -43,7 +43,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::set<int> m = {1, 2, 3, 4, 5, 6};
@@ -67,4 +67,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/find.pass.cpp b/libcxx/test/std/containers/associative/set/find.pass.cpp
index 50b779afdcf..cda1ea87aa5 100644
--- a/libcxx/test/std/containers/associative/set/find.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/find.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -237,4 +237,6 @@ int main()
     assert(r == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/gcc_workaround.pass.cpp b/libcxx/test/std/containers/associative/set/gcc_workaround.pass.cpp
index 2b923b77340..5f4947b5473 100644
--- a/libcxx/test/std/containers/associative/set/gcc_workaround.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/gcc_workaround.pass.cpp
@@ -15,7 +15,4 @@ std::set<int> s;
 using std::map;
 using std::multimap;
 
-int main(void)
-{
-       return 0;
-}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/containers/associative/set/incomplete_type.pass.cpp b/libcxx/test/std/containers/associative/set/incomplete_type.pass.cpp
index 96b2bbf5916..d3b93c59972 100644
--- a/libcxx/test/std/containers/associative/set/incomplete_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/incomplete_type.pass.cpp
@@ -23,6 +23,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 inline bool operator<(A const& L, A const& R)  { return L.data < R.data; }
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_and_emplace_allocator_requirements.pass.cpp b/libcxx/test/std/containers/associative/set/insert_and_emplace_allocator_requirements.pass.cpp
index 8c60e699af1..11be14b02b0 100644
--- a/libcxx/test/std/containers/associative/set/insert_and_emplace_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_and_emplace_allocator_requirements.pass.cpp
@@ -20,9 +20,11 @@
 #include "container_test_types.h"
 #include "../../set_allocator_requirement_test_templates.h"
 
-int main()
+int main(int, char**)
 {
   testSetInsert<TCT::set<> >();
   testSetEmplace<TCT::set<> >();
   testSetEmplaceHint<TCT::set<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_cv.pass.cpp b/libcxx/test/std/containers/associative/set/insert_cv.pass.cpp
index d29a796baa0..a97e76eb576 100644
--- a/libcxx/test/std/containers/associative/set/insert_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_cv.pass.cpp
@@ -53,7 +53,7 @@ void do_insert_cv_test()
     assert(*r.first == 3);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_cv_test<std::set<int> >();
 #if TEST_STD_VER >= 11
@@ -62,4 +62,6 @@ int main()
         do_insert_cv_test<M>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/set/insert_initializer_list.pass.cpp
index 46fdecd4fd7..ce5cc6fd2d7 100644
--- a/libcxx/test/std/containers/associative/set/insert_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_initializer_list.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::set<int> C;
@@ -56,4 +56,6 @@ int main()
     assert(*++i == V(8));
     assert(*++i == V(10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_iter_cv.pass.cpp b/libcxx/test/std/containers/associative/set/insert_iter_cv.pass.cpp
index ab8834e6af8..be27e5e4e07 100644
--- a/libcxx/test/std/containers/associative/set/insert_iter_cv.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_iter_cv.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<int> M;
@@ -69,4 +69,6 @@ int main()
         assert(*r == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_iter_iter.pass.cpp b/libcxx/test/std/containers/associative/set/insert_iter_iter.pass.cpp
index bf55e31a8be..35c2dca30f4 100644
--- a/libcxx/test/std/containers/associative/set/insert_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<int> M;
@@ -69,4 +69,6 @@ int main()
         assert(*next(m.begin(), 2) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp b/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp
index dfe3b52da6c..08eba9fe60f 100644
--- a/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<MoveOnly> M;
@@ -70,4 +70,6 @@ int main()
         assert(m.size() == 3);
         assert(*r == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_node_type.pass.cpp b/libcxx/test/std/containers/associative/set/insert_node_type.pass.cpp
index 51826f4fd5a..188aea2bb0a 100644
--- a/libcxx/test/std/containers/associative/set/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_node_type.pass.cpp
@@ -73,10 +73,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::set<int> m;
     test(m);
     std::set<int, std::less<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/associative/set/insert_node_type_hint.pass.cpp
index 2595a3ca27c..6e8c140997c 100644
--- a/libcxx/test/std/containers/associative/set/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_node_type_hint.pass.cpp
@@ -51,10 +51,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::set<int> m;
     test(m);
     std::set<int, std::less<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/insert_rv.pass.cpp b/libcxx/test/std/containers/associative/set/insert_rv.pass.cpp
index 567243ad5b9..092fd8a710b 100644
--- a/libcxx/test/std/containers/associative/set/insert_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_rv.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<MoveOnly> M;
@@ -78,4 +78,6 @@ int main()
         assert(m.size() == 3);
         assert(*r.first == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/iterator.pass.cpp b/libcxx/test/std/containers/associative/set/iterator.pass.cpp
index 5212e3fcfa3..da0f9a7b946 100644
--- a/libcxx/test/std/containers/associative/set/iterator.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/iterator.pass.cpp
@@ -32,7 +32,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -209,4 +209,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/lower_bound.pass.cpp b/libcxx/test/std/containers/associative/set/lower_bound.pass.cpp
index b363524d412..9a25950a851 100644
--- a/libcxx/test/std/containers/associative/set/lower_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/lower_bound.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -334,4 +334,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/max_size.pass.cpp b/libcxx/test/std/containers/associative/set/max_size.pass.cpp
index 8c2c5fd281a..e37bfe7142b 100644
--- a/libcxx/test/std/containers/associative/set/max_size.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
       typedef limited_allocator<int, 10> A;
@@ -46,4 +46,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/merge.pass.cpp b/libcxx/test/std/containers/associative/set/merge.pass.cpp
index a8b22ea3df3..62e76ba069b 100644
--- a/libcxx/test/std/containers/associative/set/merge.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_comparator
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::set<int> src{1, 3, 5};
@@ -145,4 +145,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/alloc.pass.cpp
index 87bdb7aec7d..591b28c184b 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/alloc.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::less<int> C;
     typedef test_allocator<int> A;
@@ -25,4 +25,6 @@ int main()
     assert(m.empty());
     assert(m.begin() == m.end());
     assert(m.get_allocator() == A(5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/assign_initializer_list.pass.cpp
index 269ae11758f..0127b1d8147 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/assign_initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::set<int> C;
@@ -51,4 +51,6 @@ int main()
     assert(*++i == V(5));
     assert(*++i == V(6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/compare.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/compare.pass.cpp
index 4a6978d9543..a4e9718e2b4 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/compare.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > C;
     const std::set<int, C> m(C(3));
@@ -29,4 +29,6 @@ int main()
     assert(m.begin() == m.end());
     assert(m.key_comp() == C(3));
     assert(m.value_comp() == C(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/compare_alloc.pass.cpp
index 8264c3f8105..41c7d02894b 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/compare_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > C;
     typedef test_allocator<int> A;
@@ -27,4 +27,6 @@ int main()
     assert(m.begin() == m.end());
     assert(m.key_comp() == C(4));
     assert(m.get_allocator() == A(5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/associative/set/set.cons/compare_copy_constructible.fail.cpp
index 84c0b4ea0a9..58f678dd1a4 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/compare_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::set<int, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/copy.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/copy.pass.cpp
index 529d951d282..2e256aa1721 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/copy.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -91,4 +91,6 @@ int main()
         assert(*next(mo.begin(), 2) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/copy_alloc.pass.cpp
index 09e7f84ee2f..6b1010c33ff 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/copy_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef int V;
     V ar[] =
@@ -52,4 +52,6 @@ int main()
     assert(*mo.begin() == 1);
     assert(*next(mo.begin()) == 2);
     assert(*next(mo.begin(), 2) == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/copy_assign.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/copy_assign.pass.cpp
index d89c278137b..c1f37f83dcc 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/copy_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/copy_assign.pass.cpp
@@ -18,7 +18,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -105,4 +105,6 @@ int main()
         assert(*next(mo.begin()) == 2);
         assert(*next(mo.begin(), 2) == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/default.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/default.pass.cpp
index 16137d7cc97..88dc3a262c8 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/default.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::set<int> m;
@@ -50,4 +50,6 @@ int main()
     assert(m.begin() == m.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/default_noexcept.pass.cpp
index 0c25901be30..0305e20f2ee 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/default_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -53,4 +53,6 @@ int main()
         typedef std::set<MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/dtor_noexcept.pass.cpp
index 9ee68bf6d76..a06a47168d2 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/initializer_list.pass.cpp
index a0cba90bd3e..e4742bbdae0 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/initializer_list.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::set<int> C;
@@ -49,4 +49,6 @@ int main()
     assert(*++i == V(5));
     assert(*++i == V(6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare.pass.cpp
index a0448cdbcba..cf4b78af934 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef test_compare<std::less<int> > Cmp;
     typedef std::set<int, Cmp> C;
@@ -34,4 +34,6 @@ int main()
     assert(*++i == V(5));
     assert(*++i == V(6));
     assert(m.key_comp() == Cmp(10));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare_alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare_alloc.pass.cpp
index 40990948b7b..161cdd8c1c3 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/initializer_list_compare_alloc.pass.cpp
@@ -21,7 +21,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_compare<std::less<int> > Cmp;
@@ -58,4 +58,6 @@ int main()
     assert(*++i == V(6));
     assert(m.get_allocator() == A(4));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/iter_iter.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/iter_iter.pass.cpp
index 913efe0da62..25143a7df10 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/iter_iter.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -67,4 +67,6 @@ int main()
     assert(*next(m.begin(), 2) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/iter_iter_alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/iter_iter_alloc.pass.cpp
index 6e3625d0540..bf8b9709831 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/iter_iter_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/iter_iter_alloc.pass.cpp
@@ -26,7 +26,7 @@
 #include "../../../test_compare.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -83,4 +83,6 @@ int main()
     assert(m.get_allocator() == a);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/iter_iter_comp.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/iter_iter_comp.pass.cpp
index b75cccc4e40..f9c2e4a98ef 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/iter_iter_comp.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/iter_iter_comp.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_iterators.h"
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef int V;
     V ar[] =
@@ -43,4 +43,6 @@ int main()
     assert(*m.begin() == 1);
     assert(*next(m.begin()) == 2);
     assert(*next(m.begin(), 2) == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/move.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/move.pass.cpp
index b2d7b0429b8..516274efca4 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/move.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int V;
@@ -101,4 +101,6 @@ int main()
         assert(mo.size() == 0);
         assert(distance(mo.begin(), mo.end()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp
index 7bae3ed210e..db7933e92b8 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_allocator.h"
 #include "Counter.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly V;
@@ -185,4 +185,6 @@ int main()
         assert(Counter_base::gConstructed == 0);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/move_assign.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/move_assign.pass.cpp
index bbd787151ab..ba5c767f30b 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/move_assign.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly V;
@@ -180,4 +180,6 @@ int main()
         assert(m3.key_comp() == C(5));
         assert(m1.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/move_assign_noexcept.pass.cpp
index 408227e8db3..f6e3c9f32e6 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/move_assign_noexcept.pass.cpp
@@ -33,7 +33,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<MoveOnly> C;
@@ -53,4 +53,6 @@ int main()
         typedef std::set<MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/move_noexcept.pass.cpp
index 6945aa39e45..2bcd26de637 100644
--- a/libcxx/test/std/containers/associative/set/set.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/move_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_comp
     bool operator()(const T&, const T&) const { return false; }
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -51,4 +51,6 @@ int main()
         typedef std::set<MoveOnly, some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/associative/set/set.erasure/erase_if.pass.cpp
index 3eecab797af..43a60d79c02 100644
--- a/libcxx/test/std/containers/associative/set/set.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.erasure/erase_if.pass.cpp
@@ -55,7 +55,7 @@ void test()
     test0(S({1,2,3}), False, S({1,2,3}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::set<int>>();
     test<std::set<int, std::less<int>, min_allocator<int>>> ();
@@ -63,4 +63,6 @@ int main()
 
     test<std::set<long>>();
     test<std::set<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.special/member_swap.pass.cpp b/libcxx/test/std/containers/associative/set/set.special/member_swap.pass.cpp
index 02324a36aee..455c34ec89b 100644
--- a/libcxx/test/std/containers/associative/set/set.special/member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.special/member_swap.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -173,4 +173,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.special/non_member_swap.pass.cpp b/libcxx/test/std/containers/associative/set/set.special/non_member_swap.pass.cpp
index 2420dabf6a4..b111de9cac6 100644
--- a/libcxx/test/std/containers/associative/set/set.special/non_member_swap.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.special/non_member_swap.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "../../../test_compare.h"
 
-int main()
+int main(int, char**)
 {
     typedef int V;
     {
@@ -163,4 +163,6 @@ int main()
         assert(m2.key_comp() == C(1));
         assert(m2.get_allocator() == A(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp
index fc0eba646e5..9fd68f66395 100644
--- a/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp
@@ -91,7 +91,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::set<MoveOnly> C;
@@ -137,4 +137,6 @@ int main()
 #endif // _LIBCPP_VERSION
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/size.pass.cpp b/libcxx/test/std/containers/associative/set/size.pass.cpp
index 93b23472540..b73d833769c 100644
--- a/libcxx/test/std/containers/associative/set/size.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/size.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::set<int> M;
@@ -55,4 +55,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/types.pass.cpp b/libcxx/test/std/containers/associative/set/types.pass.cpp
index 3b8c0983b1e..5c7bd25a5b5 100644
--- a/libcxx/test/std/containers/associative/set/types.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/types.pass.cpp
@@ -33,7 +33,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::set<int> C;
@@ -66,4 +66,6 @@ int main()
     static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/associative/set/upper_bound.pass.cpp b/libcxx/test/std/containers/associative/set/upper_bound.pass.cpp
index 315268a600a..3649a5c0455 100644
--- a/libcxx/test/std/containers/associative/set/upper_bound.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/upper_bound.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "private_constructor.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int V;
@@ -333,4 +333,6 @@ int main()
     assert(r == next(m.begin(), 8));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.adaptors/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.adaptors/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp
index 293356b386a..59547203b49 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_alloc.pass.cpp
@@ -40,9 +40,11 @@ struct test
     using base::c;
 };
 
-int main()
+int main(int, char**)
 {
     test<int> q((test_allocator<int>(3)));
     assert(q.c.get_allocator() == test_allocator<int>(3));
     assert(q.c.size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp
index 58d61b70eb2..40f6bc473c7 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_alloc.pass.cpp
@@ -40,9 +40,11 @@ struct test
     using base::c;
 };
 
-int main()
+int main(int, char**)
 {
     test<int> q(std::less<int>(), test_allocator<int>(3));
     assert(q.c.get_allocator() == test_allocator<int>(3));
     assert(q.c.size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp
index 39c4955659b..1f3dd7fbd16 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_cont_alloc.pass.cpp
@@ -51,7 +51,7 @@ struct test
     using base::c;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::vector<int, test_allocator<int> > C;
     C v = make<C>(5);
@@ -59,4 +59,6 @@ int main()
     assert(q.c.get_allocator() == test_allocator<int>(3));
     assert(q.size() == 5);
     assert(q.top() == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp
index 4609064735f..3956f9b974e 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_comp_rcont_alloc.pass.cpp
@@ -51,11 +51,13 @@ struct test
     using base::c;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::vector<int, test_allocator<int> > C;
     test<int> q(std::less<int>(), make<C>(5), test_allocator<int>(3));
     assert(q.c.get_allocator() == test_allocator<int>(3));
     assert(q.size() == 5);
     assert(q.top() == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp
index 69ed27c073c..c461718430c 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_copy_alloc.pass.cpp
@@ -45,7 +45,7 @@ struct test
     using base::c;
 };
 
-int main()
+int main(int, char**)
 {
     test<int> qo(std::less<int>(),
                       make<std::vector<int, test_allocator<int> > >(5),
@@ -54,4 +54,6 @@ int main()
     assert(q.size() == 5);
     assert(q.c.get_allocator() == test_allocator<int>(6));
     assert(q.top() == int(4));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp
index d1ca38e022b..98dc207c199 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons.alloc/ctor_move_alloc.pass.cpp
@@ -53,7 +53,7 @@ struct test
 };
 
 
-int main()
+int main(int, char**)
 {
     test<MoveOnly> qo(std::less<MoveOnly>(),
                       make<std::vector<MoveOnly, test_allocator<MoveOnly> > >(5),
@@ -62,4 +62,6 @@ int main()
     assert(q.size() == 5);
     assert(q.c.get_allocator() == test_allocator<MoveOnly>(6));
     assert(q.top() == MoveOnly(4));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_copy.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_copy.pass.cpp
index 12c64256111..5b7760d0546 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_copy.pass.cpp
@@ -24,7 +24,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v = make<std::vector<int> >(5);
     std::priority_queue<int, std::vector<int>, std::greater<int> > qo(std::greater<int>(), v);
@@ -32,4 +32,6 @@ int main()
     q = qo;
     assert(q.size() == 5);
     assert(q.top() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_move.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_move.pass.cpp
index 61499209478..20f62d9bf64 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/assign_move.pass.cpp
@@ -29,11 +29,13 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<MoveOnly> qo(std::less<MoveOnly>(), make<std::vector<MoveOnly> >(5));
     std::priority_queue<MoveOnly> q;
     q = std::move(qo);
     assert(q.size() == 5);
     assert(q.top() == MoveOnly(4));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp.pass.cpp
index a195b10fc50..02f1bcaf059 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int, std::vector<int, limited_allocator<int, 10> > > q((std::less<int>()));
     assert(q.size() == 0);
@@ -23,4 +23,6 @@ int main()
     q.push(2);
     assert(q.size() == 2);
     assert(q.top() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_container.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_container.pass.cpp
index 561b5d48ded..487b86c5f52 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_container.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_container.pass.cpp
@@ -24,10 +24,12 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v = make<std::vector<int> >(5);
     std::priority_queue<int, std::vector<int>, std::greater<int> > q(std::greater<int>(), v);
     assert(q.size() == 5);
     assert(q.top() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_rcontainer.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_rcontainer.pass.cpp
index cb3b97997fa..47980032c05 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_rcontainer.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_comp_rcontainer.pass.cpp
@@ -29,9 +29,11 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<MoveOnly> q(std::less<MoveOnly>(), make<std::vector<MoveOnly> >(5));
     assert(q.size() == 5);
     assert(q.top() == MoveOnly(4));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_copy.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_copy.pass.cpp
index 1c63f71520c..fa8bae2b91b 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_copy.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_copy.pass.cpp
@@ -24,11 +24,13 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v = make<std::vector<int> >(5);
     std::priority_queue<int, std::vector<int>, std::greater<int> > qo(std::greater<int>(), v);
     std::priority_queue<int, std::vector<int>, std::greater<int> > q = qo;
     assert(q.size() == 5);
     assert(q.top() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_default.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_default.pass.cpp
index ae0e7badb6d..4c8dd524aeb 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_default.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_default.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int, std::vector<int, limited_allocator<int, 10> > > q;
     assert(q.size() == 0);
@@ -23,4 +23,6 @@ int main()
     q.push(2);
     assert(q.size() == 2);
     assert(q.top() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter.pass.cpp
index d1cda2029ca..d2afe72cad5 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter.pass.cpp
@@ -15,11 +15,13 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     int a[] = {3, 5, 2, 0, 6, 8, 1};
     int* an = a + sizeof(a)/sizeof(a[0]);
     std::priority_queue<int> q(a, an);
     assert(q.size() == static_cast<std::size_t>(an - a));
     assert(q.top() == 8);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp.pass.cpp
index c147b5cfd50..caee12f0f5e 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp.pass.cpp
@@ -16,7 +16,7 @@
 #include <functional>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     int a[] = {3, 5, 2, 0, 6, 8, 1};
     int* an = a + sizeof(a)/sizeof(a[0]);
@@ -24,4 +24,6 @@ int main()
         q(a, an, std::greater<int>());
     assert(q.size() == static_cast<std::size_t>(an - a));
     assert(q.top() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_cont.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_cont.pass.cpp
index b5dd515da13..0b076679240 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_cont.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_cont.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = {3, 5, 2, 0, 6, 8, 1};
     const int n = sizeof(a)/sizeof(a[0]);
@@ -23,4 +23,6 @@ int main()
     std::priority_queue<int> q(a+n/2, a+n, std::less<int>(), v);
     assert(q.size() == n);
     assert(q.top() == 8);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_rcont.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_rcont.pass.cpp
index f2f78685f24..6bc4417f478 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_rcont.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_iter_iter_comp_rcont.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     int a[] = {3, 5, 2, 0, 6, 8, 1};
     const int n = sizeof(a)/sizeof(a[0]);
@@ -28,4 +28,6 @@ int main()
                                     std::vector<MoveOnly>(a, a+n/2));
     assert(q.size() == n);
     assert(q.top() == MoveOnly(8));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_move.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_move.pass.cpp
index 445bdb56675..4158012445a 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_move.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/ctor_move.pass.cpp
@@ -29,10 +29,12 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<MoveOnly> qo(std::less<MoveOnly>(), make<std::vector<MoveOnly> >(5));
     std::priority_queue<MoveOnly> q = std::move(qo);
     assert(q.size() == 5);
     assert(q.top() == MoveOnly(4));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.fail.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.fail.cpp
index a37e372edc6..a6e579a4456 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.fail.cpp
@@ -17,7 +17,7 @@
 #include <cstddef>
 
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -54,4 +54,6 @@ int main()
 //      stack<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp
index f175c7d1489..45d39ad3ed7 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/deduct.pass.cpp
@@ -38,7 +38,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -119,4 +119,6 @@ int main()
     assert(pri.size() == 4);
     assert(pri.top() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/default_noexcept.pass.cpp
index fa0e92a1663..d738a553eaf 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/default_noexcept.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -31,4 +31,6 @@ int main()
         static_assert(std::is_nothrow_default_constructible<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/dtor_noexcept.pass.cpp
index a6418a3c77b..af583a9e27a 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/dtor_noexcept.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::priority_queue<MoveOnly> C;
         static_assert(std::is_nothrow_destructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_assign_noexcept.pass.cpp
index 8c3800ba21e..3fbd53dc43e 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_assign_noexcept.pass.cpp
@@ -21,10 +21,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::priority_queue<MoveOnly> C;
         static_assert(std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_noexcept.pass.cpp
index ae6eb4b087d..7c6b5f2136f 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.cons/move_noexcept.pass.cpp
@@ -21,10 +21,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::priority_queue<MoveOnly> C;
         static_assert(std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/emplace.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/emplace.pass.cpp
index 5e5dd9f126d..928533075d0 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/emplace.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/emplace.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "../../../Emplaceable.h"
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<Emplaceable> q;
     q.emplace(1, 2.5);
@@ -28,4 +28,6 @@ int main()
     assert(q.top() == Emplaceable(3, 4.5));
     q.emplace(2, 3.5);
     assert(q.top() == Emplaceable(3, 4.5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp
index 33b97d53376..698553d33e1 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::priority_queue<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.pass.cpp
index 60499b853d1..f8f9279d576 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q;
     assert(q.empty());
@@ -23,4 +23,6 @@ int main()
     assert(!q.empty());
     q.pop();
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/pop.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/pop.pass.cpp
index b6bcb4a72f8..a6fc9509c8b 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/pop.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/pop.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q;
     q.push(1);
@@ -30,4 +30,6 @@ int main()
     assert(q.top() == 1);
     q.pop();
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push.pass.cpp
index 8edbe1ad127..01c0ab61832 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q;
     q.push(1);
@@ -24,4 +24,6 @@ int main()
     assert(q.top() == 3);
     q.push(2);
     assert(q.top() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push_rvalue.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push_rvalue.pass.cpp
index 00bdf0c7e4c..cf474dec565 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/push_rvalue.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<MoveOnly> q;
     q.push(1);
@@ -28,4 +28,6 @@ int main()
     assert(q.top() == 3);
     q.push(2);
     assert(q.top() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/size.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/size.pass.cpp
index 51eef9eda27..393a97c28a4 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/size.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/size.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q;
     assert(q.size() == 0);
@@ -23,4 +23,6 @@ int main()
     assert(q.size() == 1);
     q.pop();
     assert(q.size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/swap.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/swap.pass.cpp
index 995e1742a52..bc3f453d886 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/swap.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/swap.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q1;
     std::priority_queue<int> q2;
@@ -26,4 +26,6 @@ int main()
     assert(q1.empty());
     assert(q2.size() == 3);
     assert(q2.top() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/top.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/top.pass.cpp
index 22a8174b34f..ea0e489f617 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/top.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.members/top.pass.cpp
@@ -15,7 +15,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q;
     q.push(1);
@@ -24,4 +24,6 @@ int main()
     assert(q.top() == 3);
     q.push(2);
     assert(q.top() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap.pass.cpp
index 2c9a39f66b0..bc75df0d384 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap.pass.cpp
@@ -17,7 +17,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::priority_queue<int> q1;
     std::priority_queue<int> q2;
@@ -28,4 +28,6 @@ int main()
     assert(q1.empty());
     assert(q2.size() == 3);
     assert(q2.top() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp
index f2194ccf874..ad4254c2b79 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp
@@ -22,10 +22,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::priority_queue<MoveOnly> C;
         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/types.fail.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/types.fail.cpp
index 431a4d0d502..244028e444d 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/types.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/types.fail.cpp
@@ -27,8 +27,10 @@
 #include <cassert>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
 //  LWG#2566 says that the first template param must match the second one's value type
     std::priority_queue<double, std::deque<int>> t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/types.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/types.pass.cpp
index 6084e59069e..54712819050 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/types.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/types.pass.cpp
@@ -50,7 +50,7 @@ struct C
     typedef int size_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_same<std::priority_queue<int>::container_type, std::vector<int> >::value), "");
     static_assert(( std::is_same<std::priority_queue<int, std::deque<int> >::container_type, std::deque<int> >::value), "");
@@ -64,4 +64,6 @@ int main()
     static_assert(( std::uses_allocator<std::priority_queue<int>, std::allocator<int> >::value), "");
     static_assert((!std::uses_allocator<std::priority_queue<int, C>, std::allocator<int> >::value), "");
     test t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp
index d2a85a34847..8d916f76771 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_alloc.pass.cpp
@@ -31,8 +31,10 @@ struct test
     test_allocator<int> get_allocator() {return c.get_allocator();}
 };
 
-int main()
+int main(int, char**)
 {
     test q(test_allocator<int>(3));
     assert(q.get_allocator() == test_allocator<int>(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp
index fc3549d2da2..56272064fc2 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_container_alloc.pass.cpp
@@ -44,7 +44,7 @@ struct test
     test_allocator<int> get_allocator() {return c.get_allocator();}
 };
 
-int main()
+int main(int, char**)
 {
     C d = make<C>(5);
     test q(d, test_allocator<int>(4));
@@ -55,4 +55,6 @@ int main()
         assert(q.front() == d[i]);
         q.pop();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp
index 6c7fbbc8110..8a66c6f12e7 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_queue_alloc.pass.cpp
@@ -42,10 +42,12 @@ struct test
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
 
-int main()
+int main(int, char**)
 {
     test<int> q(make<C>(5), test_allocator<int>(4));
     test<int> q2(q, test_allocator<int>(5));
     assert(q2.get_allocator() == test_allocator<int>(5));
     assert(q2.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp
index cc6cb5cdbc9..3af4fb0dacc 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rcontainer_alloc.pass.cpp
@@ -48,9 +48,11 @@ struct test
 };
 
 
-int main()
+int main(int, char**)
 {
     test<MoveOnly> q(make<C>(5), test_allocator<MoveOnly>(4));
     assert(q.get_allocator() == test_allocator<MoveOnly>(4));
     assert(q.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp
index cac8bf3cd1f..29a742df7d4 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons.alloc/ctor_rqueue_alloc.pass.cpp
@@ -48,10 +48,12 @@ struct test
 };
 
 
-int main()
+int main(int, char**)
 {
     test<MoveOnly> q(make<C>(5), test_allocator<MoveOnly>(4));
     test<MoveOnly> q2(std::move(q), test_allocator<MoveOnly>(5));
     assert(q2.get_allocator() == test_allocator<MoveOnly>(5));
     assert(q2.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_container.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_container.pass.cpp
index e9c41a0b612..dad35d2d169 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_container.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_container.pass.cpp
@@ -24,7 +24,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::deque<int> d = make<std::deque<int> >(5);
     std::queue<int> q(d);
@@ -34,4 +34,6 @@ int main()
         assert(q.front() == d[i]);
         q.pop();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_copy.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_copy.pass.cpp
index 35c2fa0136e..19e46a23662 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_copy.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_copy.pass.cpp
@@ -23,9 +23,11 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q(make<std::deque<int> >(5));
     std::queue<int> q2 = q;
     assert(q2 == q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_default.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_default.pass.cpp
index 0a1d3dd960b..c5c8b17a690 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_default.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_default.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::queue<int, std::vector<int, limited_allocator<int, 10> > > q;
     assert(q.size() == 0);
@@ -24,4 +24,6 @@ int main()
     assert(q.size() == 2);
     assert(q.front() == 1);
     assert(q.back() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_move.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_move.pass.cpp
index a9def3e333b..c275d5d602f 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_move.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_move.pass.cpp
@@ -29,10 +29,12 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::queue<MoveOnly> q(make<std::deque<MoveOnly> >(5));
     std::queue<MoveOnly> q2 = std::move(q);
     assert(q2.size() == 5);
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_rcontainer.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_rcontainer.pass.cpp
index 00aba51c3c7..3812ce9169b 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_rcontainer.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/ctor_rcontainer.pass.cpp
@@ -29,8 +29,10 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::queue<MoveOnly> q(make<std::deque<MoveOnly> >(5));
     assert(q.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.fail.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.fail.cpp
index eecb0343b4c..00b39c6a95b 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.fail.cpp
@@ -17,7 +17,7 @@
 #include <cstddef>
 
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -42,4 +42,6 @@ int main()
 //      stack<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp
index 45a6f2e75a2..247da2a3d98 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/deduct.pass.cpp
@@ -33,7 +33,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -87,4 +87,6 @@ int main()
     assert(que.back() == 3);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/default_noexcept.pass.cpp
index a53dd949256..1200f2e2fef 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/default_noexcept.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -29,4 +29,6 @@ int main()
         static_assert(std::is_nothrow_default_constructible<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/dtor_noexcept.pass.cpp
index 4c87d15e047..18e42ea3a7e 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/dtor_noexcept.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::queue<MoveOnly> C;
         static_assert(std::is_nothrow_destructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_assign_noexcept.pass.cpp
index 93f69059fb3..a82ab8fa41c 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_assign_noexcept.pass.cpp
@@ -20,10 +20,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::queue<MoveOnly> C;
         static_assert(std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_noexcept.pass.cpp
index 24e96edc5e4..e4c170a8bb9 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.cons/move_noexcept.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -30,4 +30,6 @@ int main()
         static_assert(std::is_nothrow_move_constructible<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_copy.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_copy.pass.cpp
index 5fe6b70c64d..98385a6f7cc 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_copy.pass.cpp
@@ -23,10 +23,12 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q(make<std::deque<int> >(5));
     std::queue<int> q2;
     q2 = q;
     assert(q2 == q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_move.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_move.pass.cpp
index 87c9ad197e6..de30e5cfe2e 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/assign_move.pass.cpp
@@ -29,11 +29,13 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::queue<MoveOnly> q(make<std::deque<MoveOnly> >(5));
     std::queue<MoveOnly> q2;
     q2 = std::move(q);
     assert(q2.size() == 5);
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back.pass.cpp
index 115360e0709..cb115c70222 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.size() == 0);
@@ -22,4 +22,6 @@ int main()
     q.push(3);
     int& ir = q.back();
     assert(ir == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back_const.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back_const.pass.cpp
index 158aa83a9f0..3a6e4c89037 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back_const.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/back_const.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.size() == 0);
@@ -23,4 +23,6 @@ int main()
     const std::queue<int>& cqr = q;
     const int& cir = cqr.back();
     assert(cir == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp
index a8e8791ac69..74afcce974f 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp
@@ -37,7 +37,7 @@ void test_return_type() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<std::queue<int> > ();
     test_return_type<std::queue<int, std::list<int> > > ();
@@ -61,4 +61,6 @@ int main()
     assert(q.size() == 3);
     assert(q.front() == Emplaceable(1, 2.5));
     assert(q.back() == Emplaceable(3, 4.5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp
index f53f9a805e0..454bf32bede 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::queue<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.pass.cpp
index 095512c2124..cc0fc56b7c4 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/empty.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.empty());
@@ -21,4 +21,6 @@ int main()
     assert(!q.empty());
     q.pop();
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front.pass.cpp
index 7ce29976baf..9c8d253fb92 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.size() == 0);
@@ -22,4 +22,6 @@ int main()
     q.push(3);
     int& ir = q.front();
     assert(ir == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front_const.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front_const.pass.cpp
index edcb21ea224..5ad1ae97aae 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front_const.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/front_const.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.size() == 0);
@@ -23,4 +23,6 @@ int main()
     const std::queue<int>& cqr = q;
     const int& cir = cqr.front();
     assert(cir == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/pop.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/pop.pass.cpp
index 587cf26c3dd..128cda51237 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/pop.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/pop.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.size() == 0);
@@ -33,4 +33,6 @@ int main()
     assert(q.back() == 3);
     q.pop();
     assert(q.size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push.pass.cpp
index a9e962f8afe..b2a784ccfa8 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push.pass.cpp
@@ -13,7 +13,7 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     q.push(1);
@@ -28,4 +28,6 @@ int main()
     assert(q.size() == 3);
     assert(q.front() == 1);
     assert(q.back() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push_rv.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push_rv.pass.cpp
index aafc9563525..17c442b151e 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push_rv.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/push_rv.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     std::queue<MoveOnly> q;
     q.push(MoveOnly(1));
@@ -32,4 +32,6 @@ int main()
     assert(q.size() == 3);
     assert(q.front() == MoveOnly(1));
     assert(q.back() == MoveOnly(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/size.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/size.pass.cpp
index f3ecaa5c4f7..fb4fdfcac4d 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/size.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/size.pass.cpp
@@ -13,10 +13,12 @@
 #include <queue>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q;
     assert(q.size() == 0);
     q.push(1);
     assert(q.size() == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/swap.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/swap.pass.cpp
index 9017d21273d..3635cea4a91 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/swap.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/swap.pass.cpp
@@ -23,7 +23,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q1 = make<std::queue<int> >(5);
     std::queue<int> q2 = make<std::queue<int> >(10);
@@ -32,4 +32,6 @@ int main()
     q1.swap(q2);
     assert(q1 == q2_save);
     assert(q2 == q1_save);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.fail.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.fail.cpp
index b9e018ca13a..041008ce6aa 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.fail.cpp
@@ -12,8 +12,10 @@
 #include <cassert>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
 //  LWG#2566 says that the first template param must match the second one's value type
     std::queue<double, std::deque<int>> t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.pass.cpp
index edc41c1a352..8623710eaa2 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.defn/types.pass.cpp
@@ -43,7 +43,7 @@ struct C
     typedef int size_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_same<std::queue<int>::container_type, std::deque<int> >::value), "");
     static_assert(( std::is_same<std::queue<int, std::vector<int> >::container_type, std::vector<int> >::value), "");
@@ -54,4 +54,6 @@ int main()
     static_assert(( std::uses_allocator<std::queue<int>, std::allocator<int> >::value), "");
     static_assert((!std::uses_allocator<std::queue<int, C>, std::allocator<int> >::value), "");
     test t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.ops/eq.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.ops/eq.pass.cpp
index ee36779b5bd..b4a3327d86b 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.ops/eq.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.ops/eq.pass.cpp
@@ -27,7 +27,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q1 = make<std::queue<int> >(5);
     std::queue<int> q2 = make<std::queue<int> >(10);
@@ -36,4 +36,6 @@ int main()
     assert(q1 == q1_save);
     assert(q1 != q2);
     assert(q2 == q2_save);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.ops/lt.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.ops/lt.pass.cpp
index 66ef66c7bd4..a8eeb1be197 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.ops/lt.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.ops/lt.pass.cpp
@@ -33,7 +33,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q1 = make<std::queue<int> >(5);
     std::queue<int> q2 = make<std::queue<int> >(10);
@@ -41,4 +41,6 @@ int main()
     assert(q2 > q1);
     assert(q1 <= q2);
     assert(q2 >= q1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap.pass.cpp
index fcaec66d755..1adc4f1f474 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap.pass.cpp
@@ -24,7 +24,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::queue<int> q1 = make<std::queue<int> >(5);
     std::queue<int> q2 = make<std::queue<int> >(10);
@@ -33,4 +33,6 @@ int main()
     swap(q1, q2);
     assert(q1 == q2_save);
     assert(q2 == q1_save);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp
index 81d728a27d6..b8cc387d186 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp
@@ -21,10 +21,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::queue<MoveOnly> C;
         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp
index c0023c40138..9fb09b158df 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_alloc.pass.cpp
@@ -31,8 +31,10 @@ struct test
     test_allocator<int> get_allocator() {return c.get_allocator();}
 };
 
-int main()
+int main(int, char**)
 {
     test q(test_allocator<int>(3));
     assert(q.get_allocator() == test_allocator<int>(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp
index ef4d25e05e9..b0c6f4fcac7 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_container_alloc.pass.cpp
@@ -44,7 +44,7 @@ struct test
     test_allocator<int> get_allocator() {return c.get_allocator();}
 };
 
-int main()
+int main(int, char**)
 {
     C d = make<C>(5);
     test q(d, test_allocator<int>(4));
@@ -55,4 +55,6 @@ int main()
         assert(q.top() == d[d.size() - i - 1]);
         q.pop();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp
index f7c0a962021..0d8481228fd 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_copy_alloc.pass.cpp
@@ -42,10 +42,12 @@ struct test
     allocator_type get_allocator() {return this->c.get_allocator();}
 };
 
-int main()
+int main(int, char**)
 {
     test<int> q(make<C>(5), test_allocator<int>(4));
     test<int> q2(q, test_allocator<int>(5));
     assert(q2.get_allocator() == test_allocator<int>(5));
     assert(q2.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp
index f33f638b8e5..5181c673916 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rcontainer_alloc.pass.cpp
@@ -48,9 +48,11 @@ struct test
 };
 
 
-int main()
+int main(int, char**)
 {
     test<MoveOnly> q(make<C>(5), test_allocator<MoveOnly>(4));
     assert(q.get_allocator() == test_allocator<MoveOnly>(4));
     assert(q.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp
index 2889763ecf0..c5ff35d2d7a 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons.alloc/ctor_rqueue_alloc.pass.cpp
@@ -48,10 +48,12 @@ struct test
 };
 
 
-int main()
+int main(int, char**)
 {
     test<MoveOnly> q(make<C>(5), test_allocator<MoveOnly>(4));
     test<MoveOnly> q2(std::move(q), test_allocator<MoveOnly>(5));
     assert(q2.get_allocator() == test_allocator<MoveOnly>(5));
     assert(q2.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_container.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_container.pass.cpp
index 7db358b3f0d..c649e238f5b 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_container.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_container.pass.cpp
@@ -24,7 +24,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::deque<int> d = make<std::deque<int> >(5);
     std::stack<int> q(d);
@@ -34,4 +34,6 @@ int main()
         assert(q.top() == d[d.size() - i - 1]);
         q.pop();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_copy.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_copy.pass.cpp
index 2bbf7cc93c9..ef3606366ff 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_copy.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_copy.pass.cpp
@@ -23,9 +23,11 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q(make<std::deque<int> >(5));
     std::stack<int> q2 = q;
     assert(q2 == q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_default.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_default.pass.cpp
index 731b2fe4ec7..460cf27ec84 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_default.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_default.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::stack<int, std::vector<int, limited_allocator<int, 10> > > q;
     assert(q.size() == 0);
@@ -24,4 +24,6 @@ int main()
     q.push(2);
     assert(q.size() == 2);
     assert(q.top() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_move.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_move.pass.cpp
index e5c846df173..86f4414c91e 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_move.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_move.pass.cpp
@@ -29,10 +29,12 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::stack<MoveOnly> q(make<std::deque<MoveOnly> >(5));
     std::stack<MoveOnly> q2 = std::move(q);
     assert(q2.size() == 5);
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_rcontainer.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_rcontainer.pass.cpp
index 9ead9152166..28fb5655f94 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_rcontainer.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/ctor_rcontainer.pass.cpp
@@ -29,8 +29,10 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::stack<MoveOnly> q(make<std::deque<MoveOnly> >(5));
     assert(q.size() == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.fail.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.fail.cpp
index bfddd8b598c..894906fc43f 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.fail.cpp
@@ -24,7 +24,7 @@
 #include <cstddef>
 
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -49,4 +49,6 @@ int main()
 //      stack<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp
index ec724b063b5..dd5ab91a09c 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/deduct.pass.cpp
@@ -35,7 +35,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -90,4 +90,6 @@ int main()
     assert(stk.top() == 3);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/default_noexcept.pass.cpp
index 2e901843ef7..d06e2865e8a 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/default_noexcept.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -30,4 +30,6 @@ int main()
         static_assert(std::is_nothrow_default_constructible<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/dtor_noexcept.pass.cpp
index 616f464186e..7c5fd648684 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/dtor_noexcept.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::stack<MoveOnly> C;
         static_assert(std::is_nothrow_destructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_assign_noexcept.pass.cpp
index 0e97c0ff66d..6ed6b8250aa 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_assign_noexcept.pass.cpp
@@ -20,10 +20,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::stack<MoveOnly> C;
         static_assert(std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_noexcept.pass.cpp
index e7743ad9807..ddf07c42468 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.cons/move_noexcept.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -29,4 +29,6 @@ int main()
         static_assert(std::is_nothrow_move_constructible<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_copy.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_copy.pass.cpp
index 0f8bf035d98..df34e4c63c8 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_copy.pass.cpp
@@ -23,10 +23,12 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q(make<std::deque<int> >(5));
     std::stack<int> q2;
     q2 = q;
     assert(q2 == q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_move.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_move.pass.cpp
index 16609e983be..ad77defe214 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/assign_move.pass.cpp
@@ -29,11 +29,13 @@ make(int n)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::stack<MoveOnly> q(make<std::deque<MoveOnly> >(5));
     std::stack<MoveOnly> q2;
     q2 = std::move(q);
     assert(q2.size() == 5);
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp
index 605440bc48f..1aa6b62c7bb 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp
@@ -36,7 +36,7 @@ void test_return_type() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<std::stack<int> > ();
     test_return_type<std::stack<int, std::vector<int> > > ();
@@ -57,4 +57,6 @@ int main()
 #endif
     assert(q.size() == 3);
     assert(q.top() == Emplaceable(3, 4.5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp
index afdd996ad70..54cd986295a 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::stack<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.pass.cpp
index 37bf18e2d63..a51045e613d 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/empty.pass.cpp
@@ -13,7 +13,7 @@
 #include <stack>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q;
     assert(q.empty());
@@ -21,4 +21,6 @@ int main()
     assert(!q.empty());
     q.pop();
     assert(q.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/pop.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/pop.pass.cpp
index 756eb01c033..95472d7e2c6 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/pop.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/pop.pass.cpp
@@ -13,7 +13,7 @@
 #include <stack>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q;
     assert(q.size() == 0);
@@ -30,4 +30,6 @@ int main()
     assert(q.top() == 1);
     q.pop();
     assert(q.size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push.pass.cpp
index 19615a031dd..70c085f17dd 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push.pass.cpp
@@ -13,7 +13,7 @@
 #include <stack>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q;
     q.push(1);
@@ -25,4 +25,6 @@ int main()
     q.push(3);
     assert(q.size() == 3);
     assert(q.top() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push_rv.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push_rv.pass.cpp
index f8ad69e99d6..8969d237b54 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push_rv.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/push_rv.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     std::stack<MoveOnly> q;
     q.push(MoveOnly(1));
@@ -29,4 +29,6 @@ int main()
     q.push(MoveOnly(3));
     assert(q.size() == 3);
     assert(q.top() == MoveOnly(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/size.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/size.pass.cpp
index 2e2f945b23d..26f2e22ee8e 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/size.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/size.pass.cpp
@@ -13,10 +13,12 @@
 #include <stack>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q;
     assert(q.size() == 0);
     q.push(1);
     assert(q.size() == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/swap.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/swap.pass.cpp
index 10c44c0df3d..88ec3cdfe3d 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/swap.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/swap.pass.cpp
@@ -23,7 +23,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q1 = make<std::stack<int> >(5);
     std::stack<int> q2 = make<std::stack<int> >(10);
@@ -32,4 +32,6 @@ int main()
     q1.swap(q2);
     assert(q1 == q2_save);
     assert(q2 == q1_save);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top.pass.cpp
index f58effe196e..6923cc9d27b 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top.pass.cpp
@@ -13,7 +13,7 @@
 #include <stack>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q;
     assert(q.size() == 0);
@@ -22,4 +22,6 @@ int main()
     q.push(3);
     int& ir = q.top();
     assert(ir == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top_const.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top_const.pass.cpp
index 348946baa6b..a5e8c49fa20 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top_const.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/top_const.pass.cpp
@@ -13,7 +13,7 @@
 #include <stack>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q;
     assert(q.size() == 0);
@@ -23,4 +23,6 @@ int main()
     const std::stack<int>& cqr = q;
     const int& cir = cqr.top();
     assert(cir == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.fail.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.fail.cpp
index f343fa109d3..d5fe97fd5d7 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.fail.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.fail.cpp
@@ -27,8 +27,10 @@
 #include <cassert>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
 //  LWG#2566 says that the first template param must match the second one's value type
     std::stack<double, std::deque<int>> t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.pass.cpp
index 33308c1adee..55fc27f8430 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.defn/types.pass.cpp
@@ -44,7 +44,7 @@ struct C
     typedef int size_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_same<std::stack<int>::container_type, std::deque<int> >::value), "");
     static_assert(( std::is_same<std::stack<int, std::vector<int> >::container_type, std::vector<int> >::value), "");
@@ -55,4 +55,6 @@ int main()
     static_assert(( std::uses_allocator<std::stack<int>, std::allocator<int> >::value), "");
     static_assert((!std::uses_allocator<std::stack<int, C>, std::allocator<int> >::value), "");
     test t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.ops/eq.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.ops/eq.pass.cpp
index a6e60f1e0d1..306869f0e9b 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.ops/eq.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.ops/eq.pass.cpp
@@ -27,7 +27,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q1 = make<std::stack<int> >(5);
     std::stack<int> q2 = make<std::stack<int> >(10);
@@ -36,4 +36,6 @@ int main()
     assert(q1 == q1_save);
     assert(q1 != q2);
     assert(q2 == q2_save);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.ops/lt.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.ops/lt.pass.cpp
index 5494b3dae71..3c8734befda 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.ops/lt.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.ops/lt.pass.cpp
@@ -33,7 +33,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q1 = make<std::stack<int> >(5);
     std::stack<int> q2 = make<std::stack<int> >(10);
@@ -41,4 +41,6 @@ int main()
     assert(q2 > q1);
     assert(q1 <= q2);
     assert(q2 >= q1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap.pass.cpp
index f8f0ed919b8..cb1323b5873 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap.pass.cpp
@@ -24,7 +24,7 @@ make(int n)
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     std::stack<int> q1 = make<std::stack<int> >(5);
     std::stack<int> q2 = make<std::stack<int> >(10);
@@ -33,4 +33,6 @@ int main()
     swap(q1, q2);
     assert(q1 == q2_save);
     assert(q2 == q1_save);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp
index 43195ecc8b9..415ea607e17 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp
@@ -21,10 +21,12 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::stack<MoveOnly> C;
         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.node/node_handle.pass.cpp b/libcxx/test/std/containers/container.node/node_handle.pass.cpp
index 37bb73197af..40cd8d0499a 100644
--- a/libcxx/test/std/containers/container.node/node_handle.pass.cpp
+++ b/libcxx/test/std/containers/container.node/node_handle.pass.cpp
@@ -128,7 +128,7 @@ void test_insert_return_type()
     test_typedef<typename Container::insert_return_type>();
 }
 
-int main()
+int main(int, char**)
 {
     test_node_handle_operations<std::map<int, int>>();
     test_node_handle_operations_multi<std::multimap<int, int>>();
@@ -143,4 +143,6 @@ int main()
     test_insert_return_type<std::set<int>>();
     test_insert_return_type<std::unordered_map<int, int>>();
     test_insert_return_type<std::unordered_set<int>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/associative.reqmts/associative.reqmts.except/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/associative.reqmts/associative.reqmts.except/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/associative.reqmts/associative.reqmts.except/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/associative.reqmts/associative.reqmts.except/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/associative.reqmts/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/associative.reqmts/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/associative.reqmts/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/associative.reqmts/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/container.requirements.dataraces/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/container.requirements.dataraces/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/container.requirements.dataraces/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/container.requirements.dataraces/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/container.requirements.general/allocator_move.pass.cpp b/libcxx/test/std/containers/container.requirements/container.requirements.general/allocator_move.pass.cpp
index 3914affd306..98c291c2e45 100644
--- a/libcxx/test/std/containers/container.requirements/container.requirements.general/allocator_move.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/container.requirements.general/allocator_move.pass.cpp
@@ -61,7 +61,7 @@ void test(int expected_num_allocs = 1) {
   }
 }
 
-int main() {
+int main(int, char**) {
   { // test sequence containers
     test<std::vector<int, test_allocator<int> > >();
     test<std::vector<bool, test_allocator<bool> > >();
@@ -102,4 +102,6 @@ int main() {
     test<std::unordered_multimap<int, int, std::hash<int>, std::equal_to<int>,
                                  test_allocator<KV> > >(stored_allocators);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/container.requirements.general/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/container.requirements.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/container.requirements.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/container.requirements.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/sequence.reqmts/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/sequence.reqmts/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/sequence.reqmts/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/sequence.reqmts/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/unord.req/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/unord.req/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/unord.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/unord.req/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/container.requirements/unord.req/unord.req.except/nothing_to_do.pass.cpp b/libcxx/test/std/containers/container.requirements/unord.req/unord.req.except/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/container.requirements/unord.req/unord.req.except/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/container.requirements/unord.req/unord.req.except/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/containers.general/nothing_to_do.pass.cpp b/libcxx/test/std/containers/containers.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/containers.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/containers.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/nothing_to_do.pass.cpp b/libcxx/test/std/containers/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.cons/deduct.fail.cpp b/libcxx/test/std/containers/sequences/array/array.cons/deduct.fail.cpp
index fb882eea071..0c0d32f69c1 100644
--- a/libcxx/test/std/containers/sequences/array/array.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.cons/deduct.fail.cpp
@@ -28,9 +28,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::array arr{1,2,3L}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'array'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.cons/deduct.pass.cpp b/libcxx/test/std/containers/sequences/array/array.cons/deduct.pass.cpp
index fead8cacfde..141aafc2a31 100644
--- a/libcxx/test/std/containers/sequences/array/array.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.cons/deduct.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -61,4 +61,6 @@ int main()
     assert(arr[0] == 4.0);
     assert(arr[1] == 5.0);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.cons/default.pass.cpp b/libcxx/test/std/containers/sequences/array/array.cons/default.pass.cpp
index 22ed4d8320f..daa6a525210 100644
--- a/libcxx/test/std/containers/sequences/array/array.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.cons/default.pass.cpp
@@ -21,7 +21,7 @@ struct NoDefault {
   NoDefault(int) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -44,4 +44,6 @@ int main()
       C c2 = {{}};
       assert(c2.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.cons/implicit_copy.pass.cpp b/libcxx/test/std/containers/sequences/array/array.cons/implicit_copy.pass.cpp
index 9d82c93b52c..c0e205c8322 100644
--- a/libcxx/test/std/containers/sequences/array/array.cons/implicit_copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.cons/implicit_copy.pass.cpp
@@ -32,7 +32,7 @@ struct NoDefault {
   NoDefault(int) {}
 };
 
-int main() {
+int main(int, char**) {
   {
     typedef double T;
     typedef std::array<T, 3> C;
@@ -89,4 +89,6 @@ int main() {
     TEST_NOT_COPY_ASSIGNABLE(C);
   }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/array/array.cons/initializer_list.pass.cpp
index 6a9da4e4fdd..e85269796fb 100644
--- a/libcxx/test/std/containers/sequences/array/array.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.cons/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         C c = {};
         assert(c.size() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp b/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp
index 36640160ee2..ce1843eb549 100644
--- a/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp
@@ -25,7 +25,7 @@ struct NoDefault {
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -67,4 +67,6 @@ int main()
       T* p = c.data();
       LIBCPP_ASSERT(p != nullptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp b/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp
index 3b035e67ca9..32c05d7ef35 100644
--- a/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp
@@ -24,7 +24,7 @@ struct NoDefault {
   NoDefault(int) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -70,4 +70,6 @@ int main()
         static_assert ( *c2.data()  ==  c2[0], "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.fill/fill.fail.cpp b/libcxx/test/std/containers/sequences/array/array.fill/fill.fail.cpp
index 96641c5cb9d..9f560dab4e4 100644
--- a/libcxx/test/std/containers/sequences/array/array.fill/fill.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.fill/fill.fail.cpp
@@ -17,7 +17,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main() {
+int main(int, char**) {
   {
     typedef double T;
     typedef std::array<const T, 0> C;
@@ -25,4 +25,6 @@ int main() {
     // expected-error-re@array:* {{static_assert failed {{.*}}"cannot fill zero-sized array of type 'const T'"}}
     c.fill(5.5); // expected-note {{requested here}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.fill/fill.pass.cpp b/libcxx/test/std/containers/sequences/array/array.fill/fill.pass.cpp
index d4dfe9a7119..db7363ab975 100644
--- a/libcxx/test/std/containers/sequences/array/array.fill/fill.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.fill/fill.pass.cpp
@@ -17,7 +17,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -36,4 +36,6 @@ int main()
         c.fill(5.5);
         assert(c.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.size/size.pass.cpp b/libcxx/test/std/containers/sequences/array/array.size/size.pass.cpp
index 038df0160dc..f837bdcf8fb 100644
--- a/libcxx/test/std/containers/sequences/array/array.size/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.size/size.pass.cpp
@@ -19,7 +19,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -55,4 +55,6 @@ int main()
         static_assert(c.empty(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.special/swap.pass.cpp b/libcxx/test/std/containers/sequences/array/array.special/swap.pass.cpp
index f4751cc7661..6c9ed957b83 100644
--- a/libcxx/test/std/containers/sequences/array/array.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.special/swap.pass.cpp
@@ -35,7 +35,7 @@ std::false_type can_swap_imp(...);
 template <class Tp>
 struct can_swap : std::is_same<decltype(can_swap_imp<Tp>(0)), void> {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -81,4 +81,6 @@ int main()
         static_assert(!can_swap<C1&>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.swap/swap.fail.cpp b/libcxx/test/std/containers/sequences/array/array.swap/swap.fail.cpp
index 3e5dc815c24..90c1496156a 100644
--- a/libcxx/test/std/containers/sequences/array/array.swap/swap.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.swap/swap.fail.cpp
@@ -17,7 +17,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main() {
+int main(int, char**) {
   {
     typedef double T;
     typedef std::array<const T, 0> C;
@@ -26,4 +26,6 @@ int main() {
     // expected-error-re@array:* {{static_assert failed {{.*}}"cannot swap zero-sized array of type 'const T'"}}
     c.swap(c2); // expected-note {{requested here}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.swap/swap.pass.cpp b/libcxx/test/std/containers/sequences/array/array.swap/swap.pass.cpp
index e23daa88e79..aac8a13b29a 100644
--- a/libcxx/test/std/containers/sequences/array/array.swap/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.swap/swap.pass.cpp
@@ -27,7 +27,7 @@ private:
   NonSwappable& operator=(NonSwappable const&);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -89,4 +89,6 @@ int main()
 #endif
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/get.fail.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/get.fail.cpp
index 25bf53835a0..7bfe670b20d 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/get.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/get.fail.cpp
@@ -23,7 +23,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -32,4 +32,6 @@ int main()
         std::get<3>(c) = 5.5; // expected-note {{requested here}}
         // expected-error-re@array:* {{static_assert failed{{( due to requirement '3U[L]{0,2} < 3U[L]{0,2}')?}} "Index out of bounds in std::get<> (std::array)"}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/get.pass.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/get.pass.cpp
index bbc1c071a79..9e94417ac97 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/get.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/get.pass.cpp
@@ -30,7 +30,7 @@ struct S {
 constexpr std::array<int, 2> getArr () { return { 3, 4 }; }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -55,4 +55,6 @@ int main()
         static_assert(std::get<1>(getArr()) == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/get_const.pass.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/get_const.pass.cpp
index 7b964870b37..b22a76185b6 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/get_const.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/get_const.pass.cpp
@@ -19,7 +19,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -39,4 +39,6 @@ int main()
         static_assert(std::get<2>(c) == 3.5, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/get_const_rv.pass.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/get_const_rv.pass.cpp
index 599e919a384..ce8fc4fd365 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/get_const_rv.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/get_const_rv.pass.cpp
@@ -24,7 +24,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -47,4 +47,6 @@ int main()
     static_assert(std::get<2>(std::move(c)) == 3.5, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/get_rv.pass.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/get_rv.pass.cpp
index 77d4633db5e..d36fcdcc206 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/get_rv.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/get_rv.pass.cpp
@@ -21,7 +21,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -31,4 +31,6 @@ int main()
         T t = std::get<0>(std::move(c));
         assert(*t == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp
index 35cd9864717..a4fbd3ab4c2 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp
@@ -23,7 +23,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -31,4 +31,6 @@ int main()
         std::tuple_element<3, C> foo; // expected-note {{requested here}}
         // expected-error-re@array:* {{static_assert failed{{( due to requirement '3U[L]{0,2} < 3U[L]{0,2}')?}} "Index out of bounds in std::tuple_element<> (std::array)"}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.pass.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.pass.cpp
index 6980838ab63..fbf5210f26f 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/tuple_element.pass.cpp
@@ -46,8 +46,10 @@ void test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<double>();
     test<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.tuple/tuple_size.pass.cpp b/libcxx/test/std/containers/sequences/array/array.tuple/tuple_size.pass.cpp
index e542f34eefb..dddcbcaff7f 100644
--- a/libcxx/test/std/containers/sequences/array/array.tuple/tuple_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.tuple/tuple_size.pass.cpp
@@ -33,9 +33,11 @@ void test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<double, 0>();
     test<double, 3>();
     test<double, 5>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.zero/tested_elsewhere.pass.cpp b/libcxx/test/std/containers/sequences/array/array.zero/tested_elsewhere.pass.cpp
index ba3c5405d07..966e603d134 100644
--- a/libcxx/test/std/containers/sequences/array/array.zero/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.zero/tested_elsewhere.pass.cpp
@@ -12,6 +12,8 @@
 
 #include <array>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/at.pass.cpp b/libcxx/test/std/containers/sequences/array/at.pass.cpp
index b8d1d2b804b..0240d5a8372 100644
--- a/libcxx/test/std/containers/sequences/array/at.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/at.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool check_idx( size_t idx, double val )
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -116,4 +116,6 @@ int main()
         static_assert (check_idx(2, 3.5), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/begin.pass.cpp b/libcxx/test/std/containers/sequences/array/begin.pass.cpp
index ce023aa3890..7b26d231dbd 100644
--- a/libcxx/test/std/containers/sequences/array/begin.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/begin.pass.cpp
@@ -24,7 +24,7 @@ struct NoDefault {
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
       LIBCPP_ASSERT(ib != nullptr);
       LIBCPP_ASSERT(ie != nullptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/compare.fail.cpp b/libcxx/test/std/containers/sequences/array/compare.fail.cpp
index 1710fe7888b..47859ad49db 100644
--- a/libcxx/test/std/containers/sequences/array/compare.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/compare.fail.cpp
@@ -41,7 +41,7 @@ void test_compare(const Array& LHS, const Array& RHS) {
 
 template <int Dummy> struct NoCompare {};
 
-int main()
+int main(int, char**)
 {
   {
     typedef NoCompare<0> T;
@@ -67,4 +67,6 @@ int main()
     TEST_IGNORE_NODISCARD (c1 == c1);
     TEST_IGNORE_NODISCARD (c1 < c1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/compare.pass.cpp b/libcxx/test/std/containers/sequences/array/compare.pass.cpp
index 56eabbd00ab..c05dd19405b 100644
--- a/libcxx/test/std/containers/sequences/array/compare.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/compare.pass.cpp
@@ -28,7 +28,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
   {
     typedef int T;
@@ -58,4 +58,6 @@ int main()
   static_assert(testComparisons6(a2, a1, false, false), "");
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp b/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp
index ce953794a56..e0ab5b61c44 100644
--- a/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp
@@ -20,11 +20,13 @@ void test_contiguous ( const C &c )
         assert ( *(c.begin() + i) == *(std::addressof(*c.begin()) + i));
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
         typedef std::array<T, 3> C;
         test_contiguous (C());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/empty.fail.cpp b/libcxx/test/std/containers/sequences/array/empty.fail.cpp
index 424f715413d..3bbb3c8e1c0 100644
--- a/libcxx/test/std/containers/sequences/array/empty.fail.cpp
+++ b/libcxx/test/std/containers/sequences/array/empty.fail.cpp
@@ -20,11 +20,13 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
 
     std::array<int, 1> c;
     c.empty(); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
     std::array<int, 0> c0;
     c0.empty(); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/empty.pass.cpp b/libcxx/test/std/containers/sequences/array/empty.pass.cpp
index 48580694708..a17aa50c5b2 100644
--- a/libcxx/test/std/containers/sequences/array/empty.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::array<int, 2> C;
@@ -32,4 +32,6 @@ int main()
     ASSERT_NOEXCEPT(c.empty());
     assert( c.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/front_back.pass.cpp b/libcxx/test/std/containers/sequences/array/front_back.pass.cpp
index 13368683a56..1a714369ffc 100644
--- a/libcxx/test/std/containers/sequences/array/front_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/front_back.pass.cpp
@@ -36,7 +36,7 @@ constexpr bool check_back( double val )
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -115,4 +115,6 @@ int main()
         static_assert (check_back (3.5), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/indexing.pass.cpp b/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
index a33a597fc5e..bf55711a141 100644
--- a/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool check_idx( size_t idx, double val )
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -104,4 +104,6 @@ int main()
         static_assert (check_idx(2, 3.5), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/iterators.pass.cpp b/libcxx/test/std/containers/sequences/array/iterators.pass.cpp
index 7e4c9b75620..71fad183ff7 100644
--- a/libcxx/test/std/containers/sequences/array/iterators.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/iterators.pass.cpp
@@ -20,7 +20,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::array<int, 5> C;
@@ -141,4 +141,6 @@ int main()
         static_assert ( *std::crbegin(c) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/max_size.pass.cpp b/libcxx/test/std/containers/sequences/array/max_size.pass.cpp
index 1f3ec0472ae..a0b77392ee8 100644
--- a/libcxx/test/std/containers/sequences/array/max_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/max_size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::array<int, 2> C;
@@ -32,4 +32,6 @@ int main()
     ASSERT_NOEXCEPT(c.max_size());
     assert(c.max_size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/size_and_alignment.pass.cpp b/libcxx/test/std/containers/sequences/array/size_and_alignment.pass.cpp
index c57740bcaa5..f585da6ce7a 100644
--- a/libcxx/test/std/containers/sequences/array/size_and_alignment.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/size_and_alignment.pass.cpp
@@ -57,7 +57,9 @@ struct TEST_ALIGNAS(TEST_ALIGNOF(std::max_align_t) * 2) TestType2 {
   char data[1000];
 };
 
-int main() {
+//static_assert(sizeof(void*) == 4, "");
+
+int main(int, char**) {
   test_type<char>();
   test_type<int>();
   test_type<double>();
@@ -65,4 +67,6 @@ int main() {
   test_type<std::max_align_t>();
   test_type<TestType1>();
   test_type<TestType2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/array/types.pass.cpp b/libcxx/test/std/containers/sequences/array/types.pass.cpp
index e76c06e6d46..f86e008d2e8 100644
--- a/libcxx/test/std/containers/sequences/array/types.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/types.pass.cpp
@@ -47,7 +47,7 @@ void test_iterators() {
     static_assert((std::is_same<typename CItT::difference_type, typename C::difference_type>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -93,4 +93,6 @@ int main()
         static_assert((std::is_same<typename C::difference_type,
             typename std::iterator_traits<typename C::const_iterator>::difference_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/sequences/deque/allocator_mismatch.fail.cpp
index 769aa9ec113..287faf75ec4 100644
--- a/libcxx/test/std/containers/sequences/deque/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/sequences/deque/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <deque>
 
-int main()
+int main(int, char**)
 {
     std::deque<int, std::allocator<long> > d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/access.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/access.pass.cpp
index b63784312d2..86c518450f9 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/access.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/access.pass.cpp
@@ -47,7 +47,7 @@ make(int size, int start = 0 )
     return c;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::deque<int> c = make<std::deque<int> >(10);
@@ -87,4 +87,6 @@ int main()
         assert(c.back() == 9);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp
index 701e318973c..79e4b30b2b2 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::deque<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.pass.cpp
index 7adf6656a7e..38859411067 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::deque<int> C;
@@ -42,4 +42,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/max_size.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/max_size.pass.cpp
index d5b3cc521e6..230a46519b1 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/max_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/max_size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   {
     typedef limited_allocator<int, 10> A;
     typedef std::deque<int, A> C;
@@ -43,4 +43,6 @@ int main() {
     assert(c.max_size() <= max_dist);
     assert(c.max_size() <= alloc_max_size(c.get_allocator()));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size.pass.cpp
index 6ef329ee62f..9161592213b 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size.pass.cpp
@@ -65,7 +65,7 @@ testN(int start, int N, int M)
     test(c1, M);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -85,4 +85,6 @@ int main()
                 testN<std::deque<int, min_allocator<int>>>(rng[i], rng[j], rng[k]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size_value.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size_value.pass.cpp
index 02910d8bf50..876ff2fe5ad 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/resize_size_value.pass.cpp
@@ -65,7 +65,7 @@ testN(int start, int N, int M)
     test(c1, M, -10);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -85,4 +85,6 @@ int main()
                 testN<std::deque<int, min_allocator<int>>>(rng[i], rng[j], rng[k]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/shrink_to_fit.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/shrink_to_fit.pass.cpp
index e4f0e2bd002..bde2eaaaa38 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/shrink_to_fit.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/shrink_to_fit.pass.cpp
@@ -55,7 +55,7 @@ testN(int start, int N)
     test(c1);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -73,4 +73,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.capacity/size.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.capacity/size.pass.cpp
index 2b89c0490d9..c70abe421cf 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.capacity/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.capacity/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::deque<int> C;
@@ -58,4 +58,6 @@ int main()
     assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/alloc.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/alloc.pass.cpp
index 4dcea9782af..e2700b958a7 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/alloc.pass.cpp
@@ -26,7 +26,7 @@ test(const Allocator& a)
     assert(d.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test<int>(std::allocator<int>());
     test<NotConstructible>(test_allocator<NotConstructible>(3));
@@ -36,4 +36,6 @@ int main()
     test<int>(explicit_allocator<int>());
     test<NotConstructible>(explicit_allocator<NotConstructible>{});
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/assign_initializer_list.pass.cpp
index 5441583fa81..edca369a54a 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/assign_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::deque<int> d;
@@ -37,4 +37,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/assign_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/assign_iter_iter.pass.cpp
index 6b3b3f19a43..d59943574f0 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/assign_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/assign_iter_iter.pass.cpp
@@ -149,7 +149,9 @@ void test_emplacable_concept() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   basic_test();
   test_emplacable_concept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/assign_size_value.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/assign_size_value.pass.cpp
index ba18ab24eb3..2875a177626 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/assign_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/assign_size_value.pass.cpp
@@ -60,7 +60,7 @@ testN(int start, int N, int M)
     test(c1, M, -10);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -80,4 +80,6 @@ int main()
                 testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j], rng[k]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/copy.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/copy.pass.cpp
index bb5bb1393c0..2d42ee38a50 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/copy.pass.cpp
@@ -25,7 +25,7 @@ test(const C& x)
     assert(c == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
         int ab[] = {3, 4, 2, 8, 0, 1, 44, 34, 45, 96, 80, 1, 13, 31, 45};
@@ -57,4 +57,6 @@ int main()
         assert(v2.get_allocator() == v.get_allocator());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/copy_alloc.pass.cpp
index 138e6bdc7e0..4334fd6a539 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/copy_alloc.pass.cpp
@@ -25,7 +25,7 @@ test(const C& x, const typename C::allocator_type& a)
     assert(c.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     {
         int ab[] = {3, 4, 2, 8, 0, 1, 44, 34, 45, 96, 80, 1, 13, 31, 45};
@@ -47,4 +47,6 @@ int main()
                                                           min_allocator<int>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.fail.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.fail.cpp
index 3180384aab5..99bf89c7908 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.fail.cpp
@@ -25,7 +25,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
 
@@ -38,4 +38,6 @@ int main()
 //      deque<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.pass.cpp
index b349819cc7b..ac08613818a 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/deduct.pass.cpp
@@ -29,7 +29,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -94,4 +94,6 @@ int main()
     static_assert(std::is_same_v<decltype(deq)::allocator_type, std::allocator<long double>>, "");
     assert(deq.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/default.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/default.pass.cpp
index bb84f05f49d..f132eb5bee8 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/default.pass.cpp
@@ -29,7 +29,7 @@ test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int, std::allocator<int> >();
     test<NotConstructible, limited_allocator<NotConstructible, 1> >();
@@ -37,4 +37,6 @@ int main()
     test<int, min_allocator<int> >();
     test<NotConstructible, min_allocator<NotConstructible> >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/default_noexcept.pass.cpp
index fea4799d54d..abc3de7db99 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/default_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -49,4 +49,6 @@ int main()
         typedef std::deque<MoveOnly, some_alloc<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/dtor_noexcept.pass.cpp
index 3dcc15045e2..7e09148b4fd 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_alloc
     ~some_alloc() noexcept(false);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::deque<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list.pass.cpp
index b76d0cca578..02cbadd6c68 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::deque<int> d = {3, 4, 5, 6};
@@ -35,4 +35,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list_alloc.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list_alloc.pass.cpp
index e412e94e7e9..1450c978b68 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/initializer_list_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::deque<int, test_allocator<int>> d({3, 4, 5, 6}, test_allocator<int>(3));
@@ -38,4 +38,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter.pass.cpp
index 6c68cd09016..214ac8303bd 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter.pass.cpp
@@ -105,7 +105,9 @@ void test_emplacable_concept() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   basic_test();
   test_emplacable_concept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter_alloc.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter_alloc.pass.cpp
index c6391620b2e..c72f73a9a8a 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/iter_iter_alloc.pass.cpp
@@ -96,7 +96,9 @@ void test_emplacable_concept() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   basic_test();
   test_emplacable_concept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/move.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/move.pass.cpp
index ee628c6aa99..b8fdc989247 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/move.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         int ab[] = {3, 4, 2, 8, 0, 1, 44, 34, 45, 96, 80, 1, 13, 31, 45};
@@ -68,4 +68,6 @@ int main()
         assert(c1.size() == 0);
         assert(c3.get_allocator() == c1.get_allocator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/move_alloc.pass.cpp
index 54ce39d7e80..68dd99f105b 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/move_alloc.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         int ab[] = {3, 4, 2, 8, 0, 1, 44, 34, 45, 96, 80, 1, 13, 31, 45};
@@ -82,4 +82,6 @@ int main()
         assert(c3.get_allocator() == A());
         LIBCPP_ASSERT(c1.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign.pass.cpp
index 325f24c8018..5fcfbb8d9ba 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         int ab[] = {3, 4, 2, 8, 0, 1, 44, 34, 45, 96, 80, 1, 13, 31, 45};
@@ -85,4 +85,6 @@ int main()
         assert(c1.size() == 0);
         assert(c3.get_allocator() == A());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign_noexcept.pass.cpp
index 3facd3084dc..1d86c14aadd 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/move_assign_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::deque<MoveOnly> C;
@@ -51,4 +51,6 @@ int main()
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/move_noexcept.pass.cpp
index b5d3331f43c..8b4b4fb1fa5 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/move_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -49,4 +49,6 @@ int main()
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal.pass.cpp
index 22f015950eb..c26ddec0c19 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal.pass.cpp
@@ -24,7 +24,7 @@ test(const C& x)
     assert(c == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
         int ab[] = {3, 4, 2, 8, 0, 1, 44, 34, 45, 96, 80, 1, 13, 31, 45};
@@ -59,4 +59,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<int>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal_initializer_list.pass.cpp
index 140bb9c7647..5f415020128 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/op_equal_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::deque<int> d;
@@ -37,4 +37,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/size.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/size.pass.cpp
index fe378e58f84..b69d2bb598e 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/size.pass.cpp
@@ -86,7 +86,7 @@ test(unsigned n)
     test2<T, Allocator> ( n );
 }
 
-int main()
+int main(int, char**)
 {
     test<DefaultOnly, std::allocator<DefaultOnly> >(0);
     test<DefaultOnly, std::allocator<DefaultOnly> >(1);
@@ -113,4 +113,6 @@ int main()
     test3<int, min_allocator<int>> (3);
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/size_value.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/size_value.pass.cpp
index 8926a879396..8c432182a67 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/size_value.pass.cpp
@@ -30,7 +30,7 @@ test(unsigned n, const T& x)
         assert(*i == x);
 }
 
-int main()
+int main(int, char**)
 {
     test<int, std::allocator<int> >(0, 5);
     test<int, std::allocator<int> >(1, 10);
@@ -48,4 +48,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<int, min_allocator<int> >(4095, 90);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.cons/size_value_alloc.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.cons/size_value_alloc.pass.cpp
index 80218de7365..d7e4b3df991 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.cons/size_value_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.cons/size_value_alloc.pass.cpp
@@ -30,7 +30,7 @@ test(unsigned n, const T& x, const Allocator& a)
         assert(*i == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     std::allocator<int> a;
@@ -64,4 +64,6 @@ int main()
     test(4097, 157, a);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.erasure/erase.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.erasure/erase.pass.cpp
index 5af8faef47b..2293ef20531 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.erasure/erase.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.erasure/erase.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,1}), opt(3), S({1,2,1}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::deque<int>>();
     test<std::deque<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::deque<long>>();
     test<std::deque<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.erasure/erase_if.pass.cpp
index 181c73686e2..e0828a3fad8 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.erasure/erase_if.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,3}), False, S({1,2,3}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::deque<int>>();
     test<std::deque<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::deque<long>>();
     test<std::deque<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/clear.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/clear.pass.cpp
index 8cfa82406db..becc36878bf 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/clear.pass.cpp
@@ -17,7 +17,7 @@
 #include "../../../NotConstructible.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef NotConstructible T;
@@ -63,4 +63,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace.pass.cpp
index 78278df325c..f4713dfdfef 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace.pass.cpp
@@ -86,7 +86,7 @@ testN(int start, int N)
 }
 
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -102,4 +102,6 @@ int main()
         for (int j = 0; j < N; ++j)
             testN<std::deque<Emplaceable, min_allocator<Emplaceable>> >(rng[i], rng[j]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_back.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_back.pass.cpp
index 835a47a5e83..ae04c7d17cf 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_back.pass.cpp
@@ -74,7 +74,7 @@ testN(int start, int N)
     test(c1);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -101,4 +101,6 @@ int main()
         c.emplace_front(1, 2, 3);
         assert(c.size() == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_front.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_front.pass.cpp
index 7f0298cdf28..43d6c36d217 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/emplace_front.pass.cpp
@@ -75,7 +75,7 @@ testN(int start, int N)
 }
 
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -102,4 +102,6 @@ int main()
         c.emplace_front(1, 2, 3);
         assert(c.size() == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.invalidation.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.invalidation.pass.cpp
index 3a055df9fee..54395114a0c 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.invalidation.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.invalidation.pass.cpp
@@ -54,7 +54,7 @@ void del_at_end(C c)
     assert(&*it2 == &*it4);
 }
 
-int main()
+int main(int, char**)
 {
     std::deque<int> queue;
     for (int i = 0; i < 20; ++i)
@@ -66,4 +66,6 @@ int main()
         del_at_end(queue);
         queue.pop_back();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.pass.cpp
index 79cb562c1c5..d8db68368b0 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter.pass.cpp
@@ -88,7 +88,7 @@ testN(int start, int N)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -121,4 +121,6 @@ int main()
     assert(v.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.invalidation.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.invalidation.pass.cpp
index fd08b6afec6..3a8a06d58cf 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.invalidation.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.invalidation.pass.cpp
@@ -59,7 +59,7 @@ void del_at_end(C c, size_t num)
 }
 
 
-int main()
+int main(int, char**)
 {
     std::deque<int> queue;
     for (int i = 0; i < 20; ++i)
@@ -74,4 +74,6 @@ int main()
         }
         queue.pop_back();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.pass.cpp
index c81d9a8bbac..c738748a6f6 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/erase_iter_iter.pass.cpp
@@ -95,7 +95,7 @@ testN(int start, int N)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -127,4 +127,6 @@ int main()
     assert(v.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_initializer_list.pass.cpp
index f14da8a817b..e0da02f7e7e 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::deque<int> d(10, 1);
@@ -59,4 +59,6 @@ int main()
     assert(d[12] == 1);
     assert(d[13] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp
index cb36aa2802c..9a5f05476d3 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp
@@ -259,7 +259,7 @@ test_move()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -285,4 +285,6 @@ int main()
     test_move<std::deque<MoveOnly, min_allocator<MoveOnly> > >();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp
index a9f242706c2..eec8e0a4998 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp
@@ -91,7 +91,7 @@ testN(int start, int N)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -107,4 +107,6 @@ int main()
         for (int j = 0; j < N; ++j)
             testN<std::deque<MoveOnly, min_allocator<MoveOnly>> >(rng[i], rng[j]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_size_value.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_size_value.pass.cpp
index ced0e360ba1..0b95c8fc50a 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_size_value.pass.cpp
@@ -132,7 +132,7 @@ self_reference_test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -154,4 +154,6 @@ int main()
     self_reference_test<std::deque<int, min_allocator<int>> >();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_value.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_value.pass.cpp
index 2e16c342a72..8dc0b50b570 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_value.pass.cpp
@@ -114,7 +114,7 @@ self_reference_test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -134,4 +134,6 @@ int main()
     self_reference_test<std::deque<int, min_allocator<int>> >();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.invalidation.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.invalidation.pass.cpp
index 74c48d326f4..7b5427b8368 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.invalidation.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.invalidation.pass.cpp
@@ -34,7 +34,7 @@ void test(C c)
     assert(&*it2 == &*it4);
 }
 
-int main()
+int main(int, char**)
 {
     std::deque<int> queue;
     for (int i = 0; i < 20; ++i)
@@ -45,4 +45,6 @@ int main()
         test(queue);
         queue.pop_back();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.pass.cpp
index 1eee65186ae..b0315eb54be 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_back.pass.cpp
@@ -63,7 +63,7 @@ testN(int start, int N)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -81,4 +81,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.invalidation.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.invalidation.pass.cpp
index e773debde43..3ff1b5b9f17 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.invalidation.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.invalidation.pass.cpp
@@ -34,7 +34,7 @@ void test(C c)
     assert(&*it2 == &*it4);
 }
 
-int main()
+int main(int, char**)
 {
     std::deque<int> queue;
     for (int i = 0; i < 20; ++i)
@@ -45,4 +45,6 @@ int main()
         test(queue);
         queue.pop_back();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.pass.cpp
index 672187380a4..9d25d168492 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/pop_front.pass.cpp
@@ -63,7 +63,7 @@ testN(int start, int N)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -81,4 +81,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back.pass.cpp
index be2d72c5358..d0a73c37f99 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back.pass.cpp
@@ -53,7 +53,7 @@ void test(int size)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2046, 2047, 2048, 2049, 4094, 4095, 4096};
@@ -69,4 +69,6 @@ int main()
         test<std::deque<int, min_allocator<int>> >(rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_exception_safety.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_exception_safety.pass.cpp
index 4bd62b10919..d4c46f0bcbc 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_exception_safety.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_exception_safety.pass.cpp
@@ -64,7 +64,7 @@ CMyClass::~CMyClass() {
 
 bool operator==(const CMyClass &lhs, const CMyClass &rhs) { return lhs.equal(rhs); }
 
-int main()
+int main(int, char**)
 {
     CMyClass instance(42);
     {
@@ -98,4 +98,6 @@ int main()
         assert(vec==vec2);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp
index aa9366956ff..29354468134 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp
@@ -58,7 +58,7 @@ void test(int size)
 }
 
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2046, 2047, 2048, 2049, 4094, 4095, 4096};
@@ -72,4 +72,6 @@ int main()
     for (int j = 0; j < N; ++j)
         test<std::deque<MoveOnly, min_allocator<MoveOnly>> >(rng[j]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front.pass.cpp
index 7e4f7151c54..dee483c7957 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front.pass.cpp
@@ -62,7 +62,7 @@ testN(int start, int N)
     test(c1, -10);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -80,4 +80,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_exception_safety.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_exception_safety.pass.cpp
index a6a5200e9a8..103f2c41d58 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_exception_safety.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_exception_safety.pass.cpp
@@ -64,7 +64,7 @@ CMyClass::~CMyClass() {
 
 bool operator==(const CMyClass &lhs, const CMyClass &rhs) { return lhs.equal(rhs); }
 
-int main()
+int main(int, char**)
 {
     CMyClass instance(42);
     {
@@ -98,4 +98,6 @@ int main()
         assert(vec==vec2);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp
index 3ffde9bf34f..7a66554d127 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp
@@ -67,7 +67,7 @@ testN(int start, int N)
 }
 
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -83,4 +83,6 @@ int main()
         for (int j = 0; j < N; ++j)
             testN<std::deque<MoveOnly, min_allocator<MoveOnly>> >(rng[i], rng[j]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/copy.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/copy.pass.cpp
index f6ee7737d83..f861c424af4 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/copy.pass.cpp
@@ -66,7 +66,7 @@ void testN(int start, int N)
     assert(c1 == c2);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -84,4 +84,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/copy_backward.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/copy_backward.pass.cpp
index 2e51d13ce70..b5225ae71bc 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/copy_backward.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/copy_backward.pass.cpp
@@ -65,7 +65,7 @@ void testN(int start, int N)
     assert(c1 == c2);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -83,4 +83,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/move.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/move.pass.cpp
index d26132b3f65..d1c2a3d726a 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/move.pass.cpp
@@ -65,7 +65,7 @@ void testN(int start, int N)
     assert(c1 == c2);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -83,4 +83,6 @@ int main()
             testN<std::deque<int, min_allocator<int>> >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/move_backward.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/move_backward.pass.cpp
index 0f3ab067fc5..9193609d200 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/move_backward.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/move_backward.pass.cpp
@@ -65,7 +65,7 @@ void testN(int start, int N)
     assert(c1 == c2);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -83,4 +83,6 @@ int main()
             testN<std::deque<int, min_allocator<int> > >(rng[i], rng[j]);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/swap.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/swap.pass.cpp
index 56310b80ce8..33910e419b7 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/swap.pass.cpp
@@ -50,7 +50,7 @@ void testN(int start, int N, int M)
     assert(c2 == c1_save);
 }
 
-int main()
+int main(int, char**)
 {
     {
         int rng[] = {0, 1, 2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
@@ -106,4 +106,6 @@ int main()
         assert(c2.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp
index 7820480da5f..edbe2112895 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp
@@ -52,7 +52,7 @@ struct some_alloc2
     typedef std::true_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::deque<MoveOnly> C;
@@ -85,4 +85,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/iterators.pass.cpp b/libcxx/test/std/containers/sequences/deque/iterators.pass.cpp
index 9fe9326ec90..1f06ffde41a 100644
--- a/libcxx/test/std/containers/sequences/deque/iterators.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/iterators.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::deque<int> C;
@@ -76,4 +76,6 @@ int main()
 //         assert ( ii1 != c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/deque/types.pass.cpp b/libcxx/test/std/containers/sequences/deque/types.pass.cpp
index 1310400922f..cfab930f390 100644
--- a/libcxx/test/std/containers/sequences/deque/types.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/types.pass.cpp
@@ -71,7 +71,7 @@ test()
         typename std::iterator_traits<typename C::const_iterator>::difference_type>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<int, test_allocator<int> >();
     test<int*, std::allocator<int*> >();
@@ -100,4 +100,6 @@ int main()
             typename std::iterator_traits<typename C::const_iterator>::difference_type>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/sequences/forwardlist/allocator_mismatch.fail.cpp
index 6973d9aee3a..42fb8da918d 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <forward_list>
 
-int main()
+int main(int, char**)
 {
     std::forward_list<int, std::allocator<long> > fl;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/empty.fail.cpp b/libcxx/test/std/containers/sequences/forwardlist/empty.fail.cpp
index effcc27335b..2ca3e024e66 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/empty.fail.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::forward_list<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/empty.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/empty.pass.cpp
index 6597c66ea29..727904c9871 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/empty.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::forward_list<int> C;
@@ -42,4 +42,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.access/front.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.access/front.pass.cpp
index 26bbdb61e6e..2509e9b2c4f 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.access/front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.access/front.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -57,4 +57,6 @@ int main()
         assert(*c.begin() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.fail.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.fail.cpp
index 2057286589c..bf43ee82ca0 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.fail.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.fail.cpp
@@ -16,7 +16,7 @@
 #include "test_allocator.h"
 #include "../../../NotConstructible.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<NotConstructible> A;
@@ -26,4 +26,6 @@ int main()
         assert(c.get_allocator() == A(12));
         assert(c.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.pass.cpp
index b70b4e8a289..c362e205153 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/alloc.pass.cpp
@@ -17,7 +17,7 @@
 #include "../../../NotConstructible.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<NotConstructible> A;
@@ -45,4 +45,6 @@ int main()
         assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_copy.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_copy.pass.cpp
index 05a74d50df0..e40d405c932 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -142,4 +142,6 @@ int main()
         assert(c1.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_init.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_init.pass.cpp
index 20ed6c51a8a..40405dd2e73 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_init.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_init.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
             assert(*i == 10+n);
         assert(n == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp
index 24feee382ed..36e4ea0ca0c 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly T;
@@ -193,4 +193,6 @@ int main()
         assert(c1.get_allocator() == A());
         assert(c0.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_op_init.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_op_init.pass.cpp
index 42f0a43b932..14c098b660b 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_op_init.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_op_init.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
             assert(*i == 10+n);
         assert(n == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_range.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_range.pass.cpp
index 098702b4407..c0b934445e0 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_range.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_range.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -74,4 +74,6 @@ int main()
         assert(n == 4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_size_value.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_size_value.pass.cpp
index ec8aadf38c7..ea4cc811e4b 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_size_value.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
         assert(n == 4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy.pass.cpp
index 551eebb440c..681629a2c5e 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
         assert(c.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy_alloc.pass.cpp
index bfcb2b49052..9788ca5ff6b 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/copy_alloc.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -63,4 +63,6 @@ int main()
         assert(c.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.fail.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.fail.cpp
index 9c91a031f99..cc146316ac1 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.fail.cpp
@@ -25,7 +25,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
 
@@ -38,4 +38,6 @@ int main()
 //      forward_list<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.pass.cpp
index e4599d469ea..fd49de5814e 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/deduct.pass.cpp
@@ -29,7 +29,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -99,4 +99,6 @@ int main()
     static_assert(std::is_same_v<decltype(fwl)::allocator_type, std::allocator<long double>>, "");
     assert(std::distance(fwl.begin(), fwl.end()) == 0); // no size for forward_list
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default.pass.cpp
index 27eb1577c44..1694faf466b 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -37,4 +37,6 @@ int main()
         assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_noexcept.pass.cpp
index 99263691646..f9363feb67b 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -49,4 +49,6 @@ int main()
         typedef std::forward_list<MoveOnly, some_alloc<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_recursive.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_recursive.pass.cpp
index ab61b04f93e..98b120f5350 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_recursive.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/default_recursive.pass.cpp
@@ -19,6 +19,8 @@ struct X
     std::forward_list<X> q;
 };
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/dtor_noexcept.pass.cpp
index ce3d0f4379d..ba879964554 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_alloc
     ~some_alloc() noexcept(false);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::forward_list<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init.pass.cpp
index ac4bcf4a518..fda636073a8 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -37,4 +37,6 @@ int main()
             assert(*i == n);
         assert(n == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init_alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init_alloc.pass.cpp
index 05a31877834..cdef7c07ef5 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/init_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -42,4 +42,6 @@ int main()
         assert(n == 10);
         assert(c.get_allocator() == A());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp
index 428fa04f148..eedec348783 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly T;
@@ -67,4 +67,6 @@ int main()
         assert(c0.empty());
         assert(c.get_allocator() == A());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp
index 9337b9b0548..7db6a41e85e 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp
@@ -20,7 +20,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly T;
@@ -67,4 +67,6 @@ int main()
         assert(c0.empty());
         assert(c.get_allocator() == A());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_assign_noexcept.pass.cpp
index 502ca930e59..486c124af65 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_assign_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::forward_list<MoveOnly> C;
@@ -51,4 +51,6 @@ int main()
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_noexcept.pass.cpp
index ddd3cfe7327..5717bb89118 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -49,4 +49,6 @@ int main()
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range.pass.cpp
index fb0ec74d6eb..ce9cd59d1a3 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -44,4 +44,6 @@ int main()
         assert(n == std::end(t) - std::begin(t));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range_alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range_alloc.pass.cpp
index 30fe467fdea..1a85d3feebe 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/range_alloc.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -50,4 +50,6 @@ int main()
         assert(c.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size.pass.cpp
index 7514d263ed1..ca3931d107d 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size.pass.cpp
@@ -33,7 +33,7 @@ void check_allocator(unsigned n, Allocator const &alloc = Allocator())
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     { // test that the ctor is explicit
       typedef std::forward_list<DefaultOnly> C;
@@ -70,4 +70,6 @@ int main()
         check_allocator<T, min_allocator<T>> ( 3 );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value.pass.cpp
index eee26298e33..e3f247202d4 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -41,4 +41,6 @@ int main()
         assert(n == N);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value_alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value_alloc.pass.cpp
index 26b3f8c6f58..cc5394f5ab3 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/size_value_alloc.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -46,4 +46,6 @@ int main()
         assert(c.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase.pass.cpp
index 53e99b48c28..68a26fbc704 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,1}), opt(3), S({1,2,1}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::forward_list<int>>();
     test<std::forward_list<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::forward_list<long>>();
     test<std::forward_list<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase_if.pass.cpp
index e3e8575403e..b2106b8c8de 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.erasure/erase_if.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,3}), False, S({1,2,3}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::forward_list<int>>();
     test<std::forward_list<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::forward_list<long>>();
     test<std::forward_list<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/before_begin.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/before_begin.pass.cpp
index 726051b8e0f..638a78327df 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/before_begin.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/before_begin.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -100,4 +100,6 @@ int main()
         assert(std::distance(i, c.end()) == 11);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/iterators.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/iterators.pass.cpp
index 25c2c312bf4..e5441109bf3 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/iterators.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.iter/iterators.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -142,4 +142,6 @@ int main()
 //         assert ( ii1 != c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp
index 5f7ac62c445..8ed29ec5afd 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp
@@ -17,7 +17,7 @@
 #include "../../../NotConstructible.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef NotConstructible T;
@@ -63,4 +63,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_after.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_after.pass.cpp
index 70e7d248fad..f2581239824 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_after.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_after.pass.cpp
@@ -19,7 +19,7 @@
 #include "../../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef Emplaceable T;
@@ -83,4 +83,6 @@ int main()
         assert(*next(c.begin(), 3) == Emplaceable(2, 3.5));
         assert(distance(c.begin(), c.end()) == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_front.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_front.pass.cpp
index 121e0178c1c..1669e0c5c12 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/emplace_front.pass.cpp
@@ -21,7 +21,7 @@
 #include "../../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef Emplaceable T;
@@ -67,4 +67,6 @@ int main()
         assert(*next(c.begin()) == Emplaceable());
         assert(distance(c.begin(), c.end()) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp
index 419ce6891d4..0a431a8965d 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -151,4 +151,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp
index 563be1739b1..59e687f6c4c 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -93,4 +93,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_const.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_const.pass.cpp
index bfc8c04f19f..3ba4f9e23f1 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_const.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_const.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -83,4 +83,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_init.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_init.pass.cpp
index 1782bc7fdc0..be5c6e5176c 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_init.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_init.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -69,4 +69,6 @@ int main()
         assert(*next(c.begin(), 3) == 1);
         assert(*next(c.begin(), 4) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_range.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_range.pass.cpp
index 8ad42aced00..4cbc92edd74 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_range.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_range.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -76,4 +76,6 @@ int main()
         assert(*next(c.begin(), 4) == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_rv.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_rv.pass.cpp
index 2aa254bbf6a..2495a707a98 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_rv.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_rv.pass.cpp
@@ -18,7 +18,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly T;
@@ -84,4 +84,6 @@ int main()
         assert(*next(c.begin(), 3) == 2);
         assert(distance(c.begin(), c.end()) == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_size_value.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_size_value.pass.cpp
index e1927945af1..7898fea9219 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/insert_after_size_value.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -69,4 +69,6 @@ int main()
         assert(*next(c.begin(), 4) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/pop_front.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/pop_front.pass.cpp
index 40b092e7697..d28f10e8192 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/pop_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/pop_front.pass.cpp
@@ -16,7 +16,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -70,4 +70,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_const.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_const.pass.cpp
index 15e3bfbc184..192227ee2b1 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_const.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_const.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -43,4 +43,6 @@ int main()
         assert(distance(c.begin(), c.end()) == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_exception_safety.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_exception_safety.pass.cpp
index 3015abb76db..8b122f1f937 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_exception_safety.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_exception_safety.pass.cpp
@@ -57,7 +57,7 @@ CMyClass::~CMyClass() {
     assert(fMagicValue == kFinishedConstructionMagicValue);
 }
 
-int main()
+int main(int, char**)
 {
     CMyClass instance;
     std::forward_list<CMyClass> vec;
@@ -70,4 +70,6 @@ int main()
     }
     catch (...) {
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_rv.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_rv.pass.cpp
index e768cd0aec3..268101671cb 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_rv.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/push_front_rv.pass.cpp
@@ -18,7 +18,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef MoveOnly T;
@@ -44,4 +44,6 @@ int main()
         assert(*next(c.begin()) == 1);
         assert(distance(c.begin(), c.end()) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp
index b79e4fd36e7..ed2de980072 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp
@@ -16,7 +16,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef DefaultOnly T;
@@ -110,4 +110,6 @@ int main()
         assert(*next(c.begin(), 5) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp
index 30f99ab9670..f6f4027e0fc 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp
@@ -21,7 +21,7 @@
 #include "container_test_types.h"
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -98,4 +98,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge.pass.cpp
index c2e32a754ee..5a55ae963de 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -44,4 +44,6 @@ int main()
         assert(c1 == c3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge_pred.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge_pred.pass.cpp
index 6656f9191ae..3de61a37f72 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge_pred.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/merge_pred.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -45,4 +45,6 @@ int main()
         assert(c1 == c3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove.pass.cpp
index fec75668a65..ca3ec253da3 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove.pass.cpp
@@ -27,7 +27,7 @@ struct S {
     };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -151,4 +151,6 @@ int main()
         assert(c1 == c2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove_if.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove_if.pass.cpp
index 45a12e7e864..1b18337bc99 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove_if.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/remove_if.pass.cpp
@@ -24,7 +24,7 @@ bool g(int i)
     return i < 3;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -152,4 +152,6 @@ int main()
         assert(cp.count() == static_cast<std::size_t>(std::distance(std::begin(t1), std::end(t1))));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/reverse.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/reverse.pass.cpp
index e9fe3cae68a..82b6813fff0 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/reverse.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/reverse.pass.cpp
@@ -30,7 +30,7 @@ void test(int N)
         assert(*j == i);
 }
 
-int main()
+int main(int, char**)
 {
     for (int i = 0; i < 10; ++i)
         test<std::forward_list<int> >(i);
@@ -38,4 +38,6 @@ int main()
     for (int i = 0; i < 10; ++i)
         test<std::forward_list<int, min_allocator<int>> >(i);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort.pass.cpp
index 239e5f129d6..c76fe03ec1a 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort.pass.cpp
@@ -38,7 +38,7 @@ void test(int N)
         assert(*j == i);
 }
 
-int main()
+int main(int, char**)
 {
     for (int i = 0; i < 40; ++i)
         test<std::forward_list<int> >(i);
@@ -46,4 +46,6 @@ int main()
     for (int i = 0; i < 40; ++i)
         test<std::forward_list<int, min_allocator<int>> >(i);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort_pred.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort_pred.pass.cpp
index d7e127bf481..971508ac410 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort_pred.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/sort_pred.pass.cpp
@@ -39,7 +39,7 @@ void test(int N)
         assert(*j == N-1-i);
 }
 
-int main()
+int main(int, char**)
 {
     for (int i = 0; i < 40; ++i)
         test<std::forward_list<int> >(i);
@@ -47,4 +47,6 @@ int main()
     for (int i = 0; i < 40; ++i)
         test<std::forward_list<int, min_allocator<int>> >(i);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_flist.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_flist.pass.cpp
index 6b57b318974..e883aee2ce4 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_flist.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_flist.pass.cpp
@@ -38,7 +38,7 @@ testd(const C& c, int p, int l)
     assert(distance(c.begin(), c.end()) == size_t1 + l);
 }
 
-int main()
+int main(int, char**)
 {
     {
     // splicing different containers
@@ -72,4 +72,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_one.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_one.pass.cpp
index a192627d8d1..87b2f60e1ad 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_one.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_one.pass.cpp
@@ -75,7 +75,7 @@ tests(const C& c, int p, int f)
     assert(distance(c.begin(), c.end()) == size_t1);
 }
 
-int main()
+int main(int, char**)
 {
     {
     // splicing different containers
@@ -137,4 +137,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_range.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_range.pass.cpp
index c836a8bfe61..32050076c03 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_range.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/splice_after_range.pass.cpp
@@ -75,7 +75,7 @@ tests(const C& c, int p, int f, int l)
     assert(distance(c.begin(), c.end()) == size_t1);
 }
 
-int main()
+int main(int, char**)
 {
     {
     // splicing different containers
@@ -165,4 +165,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique.pass.cpp
index ccb0f9a8631..07a4eae97b0 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -116,4 +116,6 @@ int main()
         assert(c1 == c2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique_pred.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique_pred.pass.cpp
index 1d4a9a0f3ce..87db88080fc 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique_pred.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.ops/unique_pred.pass.cpp
@@ -21,7 +21,7 @@ bool g(int x, int y)
     return x == y;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -121,4 +121,6 @@ int main()
         assert(c1 == c2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/equal.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/equal.pass.cpp
index 9f01fed6646..a727487ed0d 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/equal.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/equal.pass.cpp
@@ -47,7 +47,7 @@ void test(int N, int M)
     }
 }
 
-int main()
+int main(int, char**)
 {
     for (int i = 0; i < 10; ++i)
         for (int j = 0; j < 10; ++j)
@@ -57,4 +57,6 @@ int main()
         for (int j = 0; j < 10; ++j)
             test<std::forward_list<int, min_allocator<int>> >(i, j);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp
index 242a00bd860..5e0438c62bf 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -256,4 +256,6 @@ int main()
         assert(c2.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp
index 44820d9d304..5b9b590d555 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -257,4 +257,6 @@ int main()
         assert(c2.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/relational.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/relational.pass.cpp
index e65e064ffda..29a180a9661 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/relational.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/relational.pass.cpp
@@ -52,7 +52,7 @@ void test(int N, int M)
         assert(c1 > c2);
 }
 
-int main()
+int main(int, char**)
 {
     for (int i = 0; i < 10; ++i)
         for (int j = 0; j < 10; ++j)
@@ -62,4 +62,6 @@ int main()
         for (int j = 0; j < 10; ++j)
             test<std::forward_list<int, min_allocator<int>> >(i, j);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp
index ae48d1a4b95..62479549584 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp
@@ -53,7 +53,7 @@ struct some_alloc2
     typedef std::true_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::forward_list<MoveOnly> C;
@@ -85,4 +85,6 @@ int main()
         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/incomplete.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/incomplete.pass.cpp
index fd789b8c895..2bdfad777e8 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/incomplete.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/incomplete.pass.cpp
@@ -33,7 +33,7 @@ struct B {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
   {
     A a;
@@ -49,4 +49,6 @@ int main()
     b.it2 = b.d.cbefore_begin();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/max_size.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/max_size.pass.cpp
index 6b93a3db60b..08d21d64116 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/max_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/max_size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
       typedef limited_allocator<int, 10> A;
@@ -44,4 +44,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/forwardlist/types.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/types.pass.cpp
index ff6c10e4630..01a7db039d4 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/types.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/types.pass.cpp
@@ -31,7 +31,7 @@
 
 struct A { std::forward_list<A> v; }; // incomplete type support
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::forward_list<char> C;
@@ -72,4 +72,6 @@ int main()
         typename std::iterator_traits<typename C::const_iterator>::difference_type>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/sequences/list/allocator_mismatch.fail.cpp
index 002954b4480..39dcde477c2 100644
--- a/libcxx/test/std/containers/sequences/list/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/sequences/list/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <list>
 
-int main()
+int main(int, char**)
 {
     std::list<int, std::allocator<long> > l;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/incomplete_type.pass.cpp b/libcxx/test/std/containers/sequences/list/incomplete_type.pass.cpp
index 04b04d0bc2f..e68f06176b7 100644
--- a/libcxx/test/std/containers/sequences/list/incomplete_type.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/incomplete_type.pass.cpp
@@ -21,6 +21,8 @@ struct A {
     std::list<A>::const_reverse_iterator crit;
 };
 
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/iterators.pass.cpp b/libcxx/test/std/containers/sequences/list/iterators.pass.cpp
index 89cc3932d56..0fe92dfba69 100644
--- a/libcxx/test/std/containers/sequences/list/iterators.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/iterators.pass.cpp
@@ -28,7 +28,7 @@ struct A
     int second;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -152,4 +152,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.capacity/empty.fail.cpp b/libcxx/test/std/containers/sequences/list/list.capacity/empty.fail.cpp
index 99325fcb67a..0cbaa464d4a 100644
--- a/libcxx/test/std/containers/sequences/list/list.capacity/empty.fail.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.capacity/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::list<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.capacity/empty.pass.cpp b/libcxx/test/std/containers/sequences/list/list.capacity/empty.pass.cpp
index 27bd73e8845..7619ec50853 100644
--- a/libcxx/test/std/containers/sequences/list/list.capacity/empty.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.capacity/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::list<int> C;
@@ -42,4 +42,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.capacity/max_size.pass.cpp b/libcxx/test/std/containers/sequences/list/list.capacity/max_size.pass.cpp
index e3da37d7397..8560a6a87f0 100644
--- a/libcxx/test/std/containers/sequences/list/list.capacity/max_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.capacity/max_size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   {
     typedef limited_allocator<int, 10> A;
     typedef std::list<int, A> C;
@@ -43,4 +43,6 @@ int main() {
     assert(c.max_size() <= max_dist);
     assert(c.max_size() <= alloc_max_size(c.get_allocator()));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.capacity/resize_size.pass.cpp b/libcxx/test/std/containers/sequences/list/list.capacity/resize_size.pass.cpp
index 04476900dd0..3c9e240d752 100644
--- a/libcxx/test/std/containers/sequences/list/list.capacity/resize_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.capacity/resize_size.pass.cpp
@@ -15,7 +15,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int> l(5, 2);
@@ -77,4 +77,6 @@ int main()
     }
 #endif  // __LIBCPP_MOVE
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.capacity/resize_size_value.pass.cpp b/libcxx/test/std/containers/sequences/list/list.capacity/resize_size_value.pass.cpp
index 404bb0c1b65..db1c1419cca 100644
--- a/libcxx/test/std/containers/sequences/list/list.capacity/resize_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.capacity/resize_size_value.pass.cpp
@@ -15,7 +15,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<double> l(5, 2);
@@ -49,4 +49,6 @@ int main()
         assert(l.back() == 3.5);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.capacity/size.pass.cpp b/libcxx/test/std/containers/sequences/list/list.capacity/size.pass.cpp
index b28b6572f9e..d4801e76c22 100644
--- a/libcxx/test/std/containers/sequences/list/list.capacity/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.capacity/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::list<int> C;
@@ -58,4 +58,6 @@ int main()
     assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/assign_copy.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/assign_copy.pass.cpp
index c4493cac787..91ac1cfa6aa 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/assign_copy.pass.cpp
@@ -15,7 +15,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int, test_allocator<int> > l(3, 2, test_allocator<int>(5));
@@ -40,4 +40,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<int>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/assign_initializer_list.pass.cpp
index 80d5ad074a9..54c91ae4a12 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/assign_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int> d;
@@ -39,4 +39,6 @@ int main()
     assert(*i++ == 5);
     assert(*i++ == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/assign_move.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/assign_move.pass.cpp
index 7400ba5ca3f..1e826ed9115 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/assign_move.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<MoveOnly, test_allocator<MoveOnly> > l(test_allocator<MoveOnly>(5));
@@ -76,4 +76,6 @@ int main()
         assert(l.empty());
         assert(l2.get_allocator() == lo.get_allocator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/copy.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/copy.pass.cpp
index 68b2e9d16f4..153cd2dbc96 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/copy.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int> l(3, 2);
@@ -50,4 +50,6 @@ int main()
         assert(l2.get_allocator() == l.get_allocator());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/copy_alloc.pass.cpp
index b722c40e602..14e95850225 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/copy_alloc.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int, test_allocator<int> > l(3, 2, test_allocator<int>(5));
@@ -38,4 +38,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<int>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/deduct.fail.cpp b/libcxx/test/std/containers/sequences/list/list.cons/deduct.fail.cpp
index 6d9833b5f87..36982263dfc 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/deduct.fail.cpp
@@ -25,7 +25,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
 
@@ -38,4 +38,6 @@ int main()
 //      deque<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/deduct.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/deduct.pass.cpp
index 20c017500e0..03d3f38187e 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/deduct.pass.cpp
@@ -29,7 +29,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -99,4 +99,6 @@ int main()
     static_assert(std::is_same_v<decltype(lst)::allocator_type, std::allocator<long double>>, "");
     assert(lst.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/default.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/default.pass.cpp
index ffbfa0b21dc..348390c4586 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/default.pass.cpp
@@ -15,7 +15,7 @@
 #include "DefaultOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int> l;
@@ -64,4 +64,6 @@ int main()
         assert(std::distance(l.begin(), l.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/default_noexcept.pass.cpp
index b41f7320d0f..93951e96361 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/default_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -49,4 +49,6 @@ int main()
         typedef std::list<MoveOnly, some_alloc<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/default_stack_alloc.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/default_stack_alloc.pass.cpp
index 1596a4e44b2..2e0b5203b8e 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/default_stack_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/default_stack_alloc.pass.cpp
@@ -15,7 +15,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int> l;
@@ -44,4 +44,6 @@ int main()
         assert(std::distance(l.begin(), l.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/dtor_noexcept.pass.cpp
index 64894dc38dd..62af49e639a 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_alloc
     ~some_alloc() noexcept(false);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::list<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/initializer_list.pass.cpp
index 61a277395e5..bd4ffeb1371 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int> d = {3, 4, 5, 6};
@@ -37,4 +37,6 @@ int main()
     assert(*i++ == 5);
     assert(*i++ == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/initializer_list_alloc.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/initializer_list_alloc.pass.cpp
index ec560ef8d34..f6eca2112e1 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/initializer_list_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/initializer_list_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int, test_allocator<int>> d({3, 4, 5, 6}, test_allocator<int>(3));
@@ -40,4 +40,6 @@ int main()
     assert(*i++ == 5);
     assert(*i++ == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/input_iterator.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/input_iterator.pass.cpp
index ef6e11b25f1..f7491f4501f 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/input_iterator.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/input_iterator.pass.cpp
@@ -244,10 +244,12 @@ void test_ctor_under_alloc_with_alloc() {
 
 
 
-int main() {
+int main(int, char**) {
   basic_test();
   test_emplacable_concept();
   test_emplacable_concept_with_alloc();
   test_ctor_under_alloc();
   test_ctor_under_alloc_with_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/move.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/move.pass.cpp
index 9ad55ecdb01..a79a3723231 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/move.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<MoveOnly, test_allocator<MoveOnly> > l(test_allocator<MoveOnly>(5));
@@ -59,4 +59,6 @@ int main()
         assert(l.empty());
         assert(l2.get_allocator() == lo.get_allocator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/move_alloc.pass.cpp
index 80ef7cdde0a..d18ea2c4a0f 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/move_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<MoveOnly, test_allocator<MoveOnly> > l(test_allocator<MoveOnly>(5));
@@ -72,4 +72,6 @@ int main()
         assert(l.empty());
         assert(l2.get_allocator() == min_allocator<MoveOnly>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/move_assign_noexcept.pass.cpp
index b12e3d9e3b7..c6c714595b4 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/move_assign_noexcept.pass.cpp
@@ -31,7 +31,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::list<MoveOnly> C;
@@ -51,4 +51,6 @@ int main()
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/move_noexcept.pass.cpp
index 1b40bbdff25..43abd019ad4 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/move_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -49,4 +49,6 @@ int main()
         typedef std::list<MoveOnly, some_alloc<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/op_equal_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/op_equal_initializer_list.pass.cpp
index b0d6a374e1c..58ea88f4315 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/op_equal_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/op_equal_initializer_list.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int> d;
@@ -38,4 +38,6 @@ int main()
     assert(*i++ == 5);
     assert(*i++ == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/size_type.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/size_type.pass.cpp
index f11d617e134..ef365d09fd4 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/size_type.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/size_type.pass.cpp
@@ -37,7 +37,7 @@ test3(unsigned n, Allocator const &alloc = Allocator())
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int> l(3);
@@ -100,4 +100,6 @@ int main()
         assert(std::distance(l.begin(), l.end()) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.cons/size_value_alloc.pass.cpp b/libcxx/test/std/containers/sequences/list/list.cons/size_value_alloc.pass.cpp
index 25b3425abe3..282de37bbc5 100644
--- a/libcxx/test/std/containers/sequences/list/list.cons/size_value_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.cons/size_value_alloc.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::list<int> l(3, 2);
@@ -76,4 +76,6 @@ int main()
         assert(*i == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.erasure/erase.pass.cpp b/libcxx/test/std/containers/sequences/list/list.erasure/erase.pass.cpp
index 6f0b5fc8925..9c03c728248 100644
--- a/libcxx/test/std/containers/sequences/list/list.erasure/erase.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.erasure/erase.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,1}), opt(3), S({1,2,1}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::list<int>>();
     test<std::list<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::list<long>>();
     test<std::list<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/sequences/list/list.erasure/erase_if.pass.cpp
index 152f6663315..f25d3e830f2 100644
--- a/libcxx/test/std/containers/sequences/list/list.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.erasure/erase_if.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,3}), False, S({1,2,3}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::list<int>>();
     test<std::list<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::list<long>>();
     test<std::list<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/clear.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/clear.pass.cpp
index ba9e413e52a..0afd0a54835 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/clear.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a[] = {1, 2, 3};
@@ -34,4 +34,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/emplace.pass.cpp
index 5183cd9a7f2..642e8434221 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/emplace.pass.cpp
@@ -34,7 +34,7 @@ public:
     double getd() const {return d_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
     std::list<A> c;
@@ -63,4 +63,6 @@ int main()
     assert(c.back().getd() == 4.5);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_back.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_back.pass.cpp
index ca428ec6506..b7eaa7047bd 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_back.pass.cpp
@@ -34,7 +34,7 @@ public:
     double getd() const {return d_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
     std::list<A> c;
@@ -84,4 +84,6 @@ int main()
     assert(c.back().geti() == 3);
     assert(c.back().getd() == 4.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_front.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_front.pass.cpp
index 25d7eb37d3b..eece4186caa 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/emplace_front.pass.cpp
@@ -33,7 +33,7 @@ public:
     double getd() const {return d_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
     std::list<A> c;
@@ -84,4 +84,6 @@ int main()
     assert(c.back().geti() == 2);
     assert(c.back().getd() == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter.pass.cpp
index 824c3680644..87486b61690 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -61,4 +61,6 @@ int main()
     assert(distance(l1.begin(), l1.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter_iter.pass.cpp
index 8166efbd343..1df39913c53 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/erase_iter_iter.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     int a1[] = {1, 2, 3};
     {
@@ -80,4 +80,6 @@ int main()
         assert(i == l1.begin());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_initializer_list.pass.cpp
index 5cfde77e29b..98dcd0ba28d 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int> d(10, 1);
@@ -61,4 +61,6 @@ int main()
     assert(*i++ == 1);
     assert(*i++ == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_iter_iter.pass.cpp
index 0070266498f..22ef0f72b90 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_iter_iter.pass.cpp
@@ -81,10 +81,12 @@ void test() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::list<int> >();
 #if TEST_STD_VER >= 11
     test<std::list<int, min_allocator<int>>>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_rvalue.pass.cpp
index eefee912383..4ded48991a5 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_rvalue.pass.cpp
@@ -18,7 +18,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<MoveOnly> l1;
@@ -40,4 +40,6 @@ int main()
     assert(l1.front() == MoveOnly(2));
     assert(l1.back() == MoveOnly(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_size_value.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_size_value.pass.cpp
index 2fc8ab7c4f5..f577fc0bcb4 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_size_value.pass.cpp
@@ -44,10 +44,12 @@ void test() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::list<int> >();
 #if TEST_STD_VER >= 11
     test<std::list<int, min_allocator<int>>>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_value.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_value.pass.cpp
index 614f57d1263..10a3d970406 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/insert_iter_value.pass.cpp
@@ -46,10 +46,12 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::list<int> >();
 #if TEST_STD_VER >= 11
     test<std::list<int, min_allocator<int>>>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/pop_back.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/pop_back.pass.cpp
index 7247e828dda..c4c88d421d6 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/pop_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/pop_back.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a[] = {1, 2, 3};
@@ -40,4 +40,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/pop_front.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/pop_front.pass.cpp
index 9a0104d030a..3decb94c421 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/pop_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/pop_front.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a[] = {1, 2, 3};
@@ -39,4 +39,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/push_back.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/push_back.pass.cpp
index dba7c0f681e..e4aa404416f 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/push_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/push_back.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int> c;
@@ -33,4 +33,6 @@ int main()
     assert((c == std::list<int, min_allocator<int>>(a, a+5)));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_exception_safety.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_exception_safety.pass.cpp
index f2b7664a15d..a6bbc256e0b 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_exception_safety.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_exception_safety.pass.cpp
@@ -57,7 +57,7 @@ CMyClass::~CMyClass() {
     assert(fMagicValue == kFinishedConstructionMagicValue);
 }
 
-int main()
+int main(int, char**)
 {
     CMyClass instance;
     std::list<CMyClass> vec;
@@ -70,4 +70,6 @@ int main()
     }
     catch (...) {
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_rvalue.pass.cpp
index 0a4c4014b38..5894c2cc889 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/push_back_rvalue.pass.cpp
@@ -18,7 +18,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<MoveOnly> l1;
@@ -40,4 +40,6 @@ int main()
     assert(l1.front() == MoveOnly(1));
     assert(l1.back() == MoveOnly(2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/push_front.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/push_front.pass.cpp
index 980b2515eb0..27e39e90a7b 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/push_front.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/push_front.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<int> c;
@@ -33,4 +33,6 @@ int main()
     assert((c == std::list<int, min_allocator<int>>(a, a+5)));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_exception_safety.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_exception_safety.pass.cpp
index 7b680396101..49f86222aee 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_exception_safety.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_exception_safety.pass.cpp
@@ -57,7 +57,7 @@ CMyClass::~CMyClass() {
     assert(fMagicValue == kFinishedConstructionMagicValue);
 }
 
-int main()
+int main(int, char**)
 {
     CMyClass instance;
     std::list<CMyClass> vec;
@@ -70,4 +70,6 @@ int main()
     }
     catch (...) {
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_rvalue.pass.cpp
index 5f74b15975f..0020112858f 100644
--- a/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.modifiers/push_front_rvalue.pass.cpp
@@ -18,7 +18,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::list<MoveOnly> l1;
@@ -40,4 +40,6 @@ int main()
     assert(l1.front() == MoveOnly(2));
     assert(l1.back() == MoveOnly(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/merge.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/merge.pass.cpp
index eb60a416547..c2a552cf62c 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/merge.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/merge.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 3, 7, 9, 10};
@@ -48,4 +48,6 @@ int main()
     assert(c2.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/merge_comp.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/merge_comp.pass.cpp
index d2d048b3831..911c3d09af1 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/merge_comp.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/merge_comp.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {10, 9, 7, 3, 1};
@@ -48,4 +48,6 @@ int main()
     assert(c2.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/remove.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/remove.pass.cpp
index db6fd89a8d9..dab23f0414f 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/remove.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/remove.pass.cpp
@@ -32,7 +32,7 @@ struct S {
   int *i_;
 };
 
-int main() {
+int main(int, char**) {
   {
     int a1[] = {1, 2, 3, 4};
     int a2[] = {1, 2, 4};
@@ -79,4 +79,6 @@ int main() {
     assert((c == std::list<int, min_allocator<int>>(a2, a2 + 3)));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/remove_if.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/remove_if.pass.cpp
index 29dfafaaa73..f903278b3f1 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/remove_if.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/remove_if.pass.cpp
@@ -29,7 +29,7 @@ bool g(int i)
 
 typedef unary_counting_predicate<bool(*)(int), int> Predicate;
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3, 4};
@@ -60,4 +60,6 @@ int main()
     assert(cp.count() == 4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/reverse.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/reverse.pass.cpp
index a8e5f50a21a..0cf1242df59 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/reverse.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/reverse.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
@@ -33,4 +33,6 @@ int main()
     assert((c1 == std::list<int, min_allocator<int>>(a2, a2+sizeof(a2)/sizeof(a2[0]))));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/sort.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/sort.pass.cpp
index 9cc92ef0d19..cd229c2d214 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/sort.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/sort.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {4, 8, 1, 0, 5, 7, 2, 3, 6, 11, 10, 9};
@@ -33,4 +33,6 @@ int main()
     assert((c1 == std::list<int, min_allocator<int>>(a2, a2+sizeof(a2)/sizeof(a2[0]))));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/sort_comp.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/sort_comp.pass.cpp
index f7dc6b0b300..a87e32acccb 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/sort_comp.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/sort_comp.pass.cpp
@@ -35,7 +35,7 @@ struct throwingLess {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {4, 8, 1, 0, 5, 7, 2, 3, 6, 11, 10, 9};
@@ -75,4 +75,6 @@ int main()
     assert((c1 == std::list<int, min_allocator<int>>(a2, a2+sizeof(a2)/sizeof(a2[0]))));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list.pass.cpp
index e1d9f4c5218..6a921e25ea9 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     int a1[] = {1, 2, 3};
     int a2[] = {4, 5, 6};
@@ -780,4 +780,6 @@ int main()
         assert(*i == 6);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter.pass.cpp
index b87e6b8252a..9388b559fd6 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     int a1[] = {1, 2, 3};
     int a2[] = {4, 5, 6};
@@ -334,4 +334,6 @@ int main()
         assert(*i == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter_iter.pass.cpp
index e4c5752df60..d22321b2440 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/splice_pos_list_iter_iter.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     int a1[] = {1, 2, 3};
     int a2[] = {4, 5, 6};
@@ -214,4 +214,6 @@ int main()
         assert(*i == 4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/unique.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/unique.pass.cpp
index e5e45949168..651ffbc7bae 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/unique.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/unique.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {2, 1, 1, 4, 4, 4, 4, 3, 3};
@@ -33,4 +33,6 @@ int main()
     assert((c == std::list<int, min_allocator<int>>(a2, a2+4)));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.ops/unique_pred.pass.cpp b/libcxx/test/std/containers/sequences/list/list.ops/unique_pred.pass.cpp
index a3f149d05ed..dd0bcd77b6f 100644
--- a/libcxx/test/std/containers/sequences/list/list.ops/unique_pred.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.ops/unique_pred.pass.cpp
@@ -20,7 +20,7 @@ bool g(int x, int y)
     return x == y;
 }
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {2, 1, 1, 4, 4, 4, 4, 3, 3};
@@ -38,4 +38,6 @@ int main()
     assert((c == std::list<int, min_allocator<int>>(a2, a2+4)));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.special/swap.pass.cpp b/libcxx/test/std/containers/sequences/list/list.special/swap.pass.cpp
index de98cfe9f2a..be7df207bdd 100644
--- a/libcxx/test/std/containers/sequences/list/list.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.special/swap.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         int a1[] = {1, 3, 7, 9, 10};
@@ -136,4 +136,6 @@ int main()
         assert(c2.get_allocator() == A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp
index c6e4f61ef2a..86634dd838d 100644
--- a/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp
@@ -52,7 +52,7 @@ struct some_alloc2
     typedef std::true_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::list<MoveOnly> C;
@@ -85,4 +85,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/list/types.pass.cpp b/libcxx/test/std/containers/sequences/list/types.pass.cpp
index bf872fffd93..914f9abab7d 100644
--- a/libcxx/test/std/containers/sequences/list/types.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/types.pass.cpp
@@ -28,7 +28,7 @@
 
 struct A { std::list<A> v; }; // incomplete type support
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::list<int> C;
@@ -65,4 +65,6 @@ int main()
         typename std::iterator_traits<typename C::const_iterator>::difference_type>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/nothing_to_do.pass.cpp b/libcxx/test/std/containers/sequences/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/containers/sequences/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/containers/sequences/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/assign_copy.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/assign_copy.pass.cpp
index cffc3bfff0f..5aa86839ff4 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/assign_copy.pass.cpp
@@ -15,7 +15,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool, test_allocator<bool> > l(3, true, test_allocator<bool>(5));
@@ -40,4 +40,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<bool>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/assign_initializer_list.pass.cpp
index 36d32c73c73..bbd980bd325 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/assign_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<bool> d;
@@ -37,4 +37,6 @@ int main()
     assert(d[2] == false);
     assert(d[3] == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/assign_move.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/assign_move.pass.cpp
index 59fb08fbf23..b70e9cde65b 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/assign_move.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool, test_allocator<bool> > l(test_allocator<bool>(5));
@@ -75,4 +75,6 @@ int main()
         assert(l.empty());
         assert(l2.get_allocator() == lo.get_allocator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/capacity.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/capacity.pass.cpp
index 14ebc6c1e63..e24ebe00c6a 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/capacity.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/capacity.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v;
@@ -40,4 +40,6 @@ int main()
         assert(v.capacity() >= 101);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/construct_default.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/construct_default.pass.cpp
index e481ece9f71..3fd2bf8d195 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/construct_default.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/construct_default.pass.cpp
@@ -59,7 +59,7 @@ test1(const typename C::allocator_type& a)
     assert(c.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     {
     test0<std::vector<bool> >();
@@ -75,4 +75,6 @@ int main()
     test1<std::vector<bool, explicit_allocator<bool> > >(explicit_allocator<bool>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter.pass.cpp
index 44931a75c6a..e20f300982c 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter.pass.cpp
@@ -30,7 +30,7 @@ test(Iterator first, Iterator last)
         assert(*i == *first);
 }
 
-int main()
+int main(int, char**)
 {
     bool a[] = {0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0};
     bool* an = a + sizeof(a)/sizeof(a[0]);
@@ -46,4 +46,6 @@ int main()
     test<std::vector<bool, min_allocator<bool>> >(random_access_iterator<const bool*>(a), random_access_iterator<const bool*>(an));
     test<std::vector<bool, min_allocator<bool>> >(a, an);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter_alloc.pass.cpp
index 49d2c23e0ea..2aa2b42648f 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/construct_iter_iter_alloc.pass.cpp
@@ -31,7 +31,7 @@ test(Iterator first, Iterator last, const typename C::allocator_type& a)
         assert(*i == *first);
 }
 
-int main()
+int main(int, char**)
 {
     bool a[] = {0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0};
     bool* an = a + sizeof(a)/sizeof(a[0]);
@@ -53,4 +53,6 @@ int main()
     test<std::vector<bool, min_allocator<bool>> >(a, an, alloc);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/construct_size.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/construct_size.pass.cpp
index 8300924b6d0..2763df7e11d 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/construct_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/construct_size.pass.cpp
@@ -56,11 +56,13 @@ test(typename C::size_type n)
     test2<C> ( n );
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<bool> >(50);
 #if TEST_STD_VER >= 11
     test<std::vector<bool, min_allocator<bool>> >(50);
     test2<std::vector<bool, test_allocator<bool>> >( 100, test_allocator<bool>(23));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/construct_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/construct_size_value.pass.cpp
index ecde4267809..068989330a3 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/construct_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/construct_size_value.pass.cpp
@@ -28,10 +28,12 @@ test(typename C::size_type n, const typename C::value_type& x)
         assert(*i == x);
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<bool> >(50, true);
 #if TEST_STD_VER >= 11
     test<std::vector<bool, min_allocator<bool>> >(50, true);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/construct_size_value_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/construct_size_value_alloc.pass.cpp
index c9439246560..e19f3c4a9d5 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/construct_size_value_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/construct_size_value_alloc.pass.cpp
@@ -30,10 +30,12 @@ test(typename C::size_type n, const typename C::value_type& x,
         assert(*i == x);
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<bool> >(50, true, std::allocator<bool>());
 #if TEST_STD_VER >= 11
     test<std::vector<bool, min_allocator<bool>> >(50, true, min_allocator<bool>());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/copy.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/copy.pass.cpp
index 66a15a4c861..618a37faf70 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/copy.pass.cpp
@@ -29,7 +29,7 @@ test(const C& x)
     assert(c == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
         bool a[] = {0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0};
@@ -61,4 +61,6 @@ int main()
         assert(v2.get_allocator() == v.get_allocator());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/copy_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/copy_alloc.pass.cpp
index 9a63e5a555d..7970b2c7ed9 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/copy_alloc.pass.cpp
@@ -28,7 +28,7 @@ test(const C& x, const typename C::allocator_type& a)
     assert(c == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
         bool a[] = {0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0};
@@ -60,4 +60,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<bool>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/default_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/default_noexcept.pass.cpp
index bffeaf64c74..800bd1b4b1c 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/default_noexcept.pass.cpp
@@ -30,7 +30,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -50,4 +50,6 @@ int main()
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/dtor_noexcept.pass.cpp
index 9d7858b4f8c..949add271a2 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/dtor_noexcept.pass.cpp
@@ -26,7 +26,7 @@ struct some_alloc
     ~some_alloc() noexcept(false);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<bool> C;
@@ -46,4 +46,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/emplace.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/emplace.pass.cpp
index 26b9039073c..129cbff154e 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/emplace.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/emplace.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<bool> C;
@@ -63,4 +63,6 @@ int main()
         assert(c[1] == true);
         assert(c.back() == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/emplace_back.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/emplace_back.pass.cpp
index 0ad72100214..974b7c24ac7 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/emplace_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/emplace_back.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<bool> C;
@@ -87,4 +87,6 @@ int main()
         assert(c[1] == true);
         assert(c.back() == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/empty.fail.cpp b/libcxx/test/std/containers/sequences/vector.bool/empty.fail.cpp
index 0381d7eb24b..0a84eb79d12 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/empty.fail.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::vector<bool> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/empty.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/empty.pass.cpp
index e3226a12835..e0c0243e139 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/empty.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<bool> C;
@@ -42,4 +42,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/enabled_hash.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/enabled_hash.pass.cpp
index ba8bdf5312a..f6631cf2d49 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/enabled_hash.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/enabled_hash.pass.cpp
@@ -18,10 +18,12 @@
 #include "poisoned_hash_helper.hpp"
 #include "min_allocator.h"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::vector<bool> >();
     test_hash_enabled_for_type<std::vector<bool, min_allocator<bool>>>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp
index b0a65c9ae27..c3d6bfd5de0 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     bool a1[] = {1, 0, 1};
     {
@@ -61,4 +61,6 @@ int main()
     assert(distance(l1.begin(), l1.end()) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp
index b574552309a..89763017e97 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     bool a1[] = {1, 0, 1};
     {
@@ -81,4 +81,6 @@ int main()
         assert(i == l1.begin());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/find.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/find.pass.cpp
index 265b519de78..883b5b4dbca 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/find.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/find.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         for (unsigned i = 1; i < 256; ++i)
@@ -38,4 +38,6 @@ int main()
             assert(b.end() == j);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/initializer_list.pass.cpp
index 9f99675896f..d510b86fed0 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<bool> d = {true, false, false, true};
@@ -35,4 +35,6 @@ int main()
     assert(d[2] == false);
     assert(d[3] == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/initializer_list_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/initializer_list_alloc.pass.cpp
index 29164b598e6..27d8420a6df 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/initializer_list_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/initializer_list_alloc.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<bool, test_allocator<bool>> d({true, false, false, true}, test_allocator<bool>(3));
@@ -38,4 +38,6 @@ int main()
     assert(d[2] == false);
     assert(d[3] == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_initializer_list.pass.cpp
index 3760a9611bb..519752da103 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<bool> d(10, true);
@@ -59,4 +59,6 @@ int main()
     assert(d[12] == true);
     assert(d[13] == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_iter_iter.pass.cpp
index 7180bb8c28b..b9a92189169 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_iter_iter.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v(100);
@@ -125,4 +125,6 @@ int main()
             assert(v[j] == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_size_value.pass.cpp
index 9e13af2ac7d..5774ab5f6ca 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_size_value.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v(100);
@@ -78,4 +78,6 @@ int main()
             assert(v[j] == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_value.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_value.pass.cpp
index 1c0e8ed03a8..2502865c78e 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/insert_iter_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/insert_iter_value.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v(100);
@@ -74,4 +74,6 @@ int main()
             assert(v[j] == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/iterators.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/iterators.pass.cpp
index 0780d1dd093..7714e53b2cd 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/iterators.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/iterators.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef bool T;
@@ -120,4 +120,6 @@ int main()
         assert (ii1 - cii == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/move.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/move.pass.cpp
index e5752e08437..4de0604c6a7 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/move.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool, test_allocator<bool> > l(test_allocator<bool>(5));
@@ -89,4 +89,6 @@ int main()
         assert(a.get_data() == 42);
       }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/move_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/move_alloc.pass.cpp
index bcf57b6c2c3..f2ff5303b0f 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/move_alloc.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool, test_allocator<bool> > l(test_allocator<bool>(5));
@@ -71,4 +71,6 @@ int main()
         assert(l.empty());
         assert(l2.get_allocator() == min_allocator<bool>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/move_assign_noexcept.pass.cpp
index 60517e20653..6c7fcfca75c 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/move_assign_noexcept.pass.cpp
@@ -56,7 +56,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -97,4 +97,6 @@ int main()
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/move_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/move_noexcept.pass.cpp
index 8326e4c4271..a59e1a8eb94 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/move_noexcept.pass.cpp
@@ -28,7 +28,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -56,4 +56,6 @@ int main()
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/op_equal_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/op_equal_initializer_list.pass.cpp
index 5263fa3bd3a..22384fe8d06 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/op_equal_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/op_equal_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<bool> d;
@@ -37,4 +37,6 @@ int main()
     assert(d[2] == false);
     assert(d[3] == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/push_back.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/push_back.pass.cpp
index 2e7d82d961b..438869be16c 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/push_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/push_back.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         bool a[] = {0, 1, 1, 0, 1, 0, 0};
@@ -45,4 +45,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/reference.swap.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/reference.swap.pass.cpp
index 22e10914225..c41bac18836 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/reference.swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/reference.swap.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 
     bool a[] = {false, true, false, true};
@@ -35,4 +35,6 @@ int main()
     v.swap(r1, r2);
     assert( r1);
     assert(!r2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/reserve.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/reserve.pass.cpp
index b7430453fae..039c1bc18fa 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/reserve.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/reserve.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v;
@@ -50,4 +50,6 @@ int main()
         assert(v.capacity() >= 150);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/resize_size.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/resize_size.pass.cpp
index 3d926910ce7..53e83ac7eff 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/resize_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/resize_size.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v(100);
@@ -46,4 +46,6 @@ int main()
         assert(v.capacity() >= 400);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/resize_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/resize_size_value.pass.cpp
index 061f8a505e4..ef0cb6160c6 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/resize_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/resize_size_value.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v(100);
@@ -48,4 +48,6 @@ int main()
             assert(v[i] == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
index 988ce6e03bf..59714d5fb5c 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v(100);
@@ -34,4 +34,6 @@ int main()
         assert(v.size() >= 101);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/size.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/size.pass.cpp
index d8abef9893f..db737c930c3 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<bool> C;
@@ -58,4 +58,6 @@ int main()
     assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/swap.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/swap.pass.cpp
index 9aa579d4a6d..9ff11113d82 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/swap.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<bool> v1(100);
@@ -94,4 +94,6 @@ int main()
         assert(v[1] == true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp
index dbf0f821f13..e346c29983f 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp
@@ -52,7 +52,7 @@ struct some_alloc2
     typedef std::true_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -89,4 +89,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/types.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/types.pass.cpp
index 4736f8ac976..d15973a38b1 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/types.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/types.pass.cpp
@@ -67,7 +67,7 @@ test()
         std::reverse_iterator<typename C::const_iterator> >::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<test_allocator<bool> >();
     test<std::allocator<bool> >();
@@ -76,4 +76,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<min_allocator<bool> >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp
index c0d27e4d294..5f9ae3decb6 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<bool> T;
@@ -50,4 +50,6 @@ int main()
     assert(h(vb) != 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/sequences/vector/allocator_mismatch.fail.cpp
index 001af629856..0c57f16be6c 100644
--- a/libcxx/test/std/containers/sequences/vector/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/sequences/vector/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <vector>
 
-int main()
+int main(int, char**)
 {
     std::vector<int, std::allocator<long> > v;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/contiguous.pass.cpp b/libcxx/test/std/containers/sequences/vector/contiguous.pass.cpp
index 2ac79be6ad1..99d9d6ecae7 100644
--- a/libcxx/test/std/containers/sequences/vector/contiguous.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/contiguous.pass.cpp
@@ -23,7 +23,7 @@ void test_contiguous ( const C &c )
         assert ( *(c.begin() + static_cast<typename C::difference_type>(i)) == *(std::addressof(*c.begin()) + i));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -48,4 +48,6 @@ int main()
     test_contiguous(C(9, 11.0, A{}));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/iterators.pass.cpp b/libcxx/test/std/containers/sequences/vector/iterators.pass.cpp
index f8b8ca3176b..296c551f76f 100644
--- a/libcxx/test/std/containers/sequences/vector/iterators.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/iterators.pass.cpp
@@ -28,7 +28,7 @@ struct A
     int second;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -166,4 +166,6 @@ int main()
         assert (ii1 - cii == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/types.pass.cpp b/libcxx/test/std/containers/sequences/vector/types.pass.cpp
index 101355bee7c..0a04c25527a 100644
--- a/libcxx/test/std/containers/sequences/vector/types.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/types.pass.cpp
@@ -78,7 +78,7 @@ test()
         std::reverse_iterator<typename C::const_iterator> >::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<int, test_allocator<int> >();
     test<int*, std::allocator<int*> >();
@@ -104,4 +104,6 @@ int main()
 //         typename std::iterator_traits<typename C::const_iterator>::difference_type>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/capacity.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/capacity.pass.cpp
index 58dccba224a..a8ee9f22962 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/capacity.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/capacity.pass.cpp
@@ -16,7 +16,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v;
@@ -44,4 +44,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp
index 8085bd4846c..0f7dc6c64cc 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::vector<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.pass.cpp
index 594b9e4f48d..cce2602bd36 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<int> C;
@@ -42,4 +42,6 @@ int main()
     assert(c.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/max_size.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/max_size.pass.cpp
index 3e18d4a4d5b..c9cc6d5821c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/max_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/max_size.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
   {
     typedef limited_allocator<int, 10> A;
     typedef std::vector<int, A> C;
@@ -44,4 +44,6 @@ int main() {
     assert(c.max_size() <= max_dist);
     assert(c.max_size() <= alloc_max_size(c.get_allocator()));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/reserve.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/reserve.pass.cpp
index 48f57c99cb4..4cf3b2d338c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/reserve.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/reserve.pass.cpp
@@ -16,7 +16,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v;
@@ -66,4 +66,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size.pass.cpp
index d4b282518fe..41188acb7d8 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v(100);
@@ -80,4 +80,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size_value.pass.cpp
index 35b63756a31..4d9f7931d8a 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/resize_size_value.pass.cpp
@@ -16,7 +16,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v(100);
@@ -73,4 +73,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/shrink_to_fit.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/shrink_to_fit.pass.cpp
index 1b8d2815ccd..36125bb932c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/shrink_to_fit.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/shrink_to_fit.pass.cpp
@@ -16,7 +16,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v(100);
@@ -58,4 +58,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/size.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/size.pass.cpp
index 8944eca422e..373a7069f3a 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<int> C;
@@ -58,4 +58,6 @@ int main()
     assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.capacity/swap.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.capacity/swap.pass.cpp
index f66eafe25f5..e2fa0d8b928 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.capacity/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.capacity/swap.pass.cpp
@@ -16,7 +16,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v1(100);
@@ -46,4 +46,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_copy.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_copy.pass.cpp
index 2c087fb498d..f6d8dd50b7e 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_copy.pass.cpp
@@ -15,7 +15,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int, test_allocator<int> > l(3, 2, test_allocator<int>(5));
@@ -40,4 +40,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<int>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_initializer_list.pass.cpp
index c64c8bf3bce..4673df9558d 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_initializer_list.pass.cpp
@@ -30,7 +30,7 @@ void test ( Vec &v )
     assert(v[3] == 6);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<int> V;
@@ -48,4 +48,6 @@ int main()
     test(d1);
     test(d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp
index 888ffb105d1..df8450210d8 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp
@@ -69,7 +69,9 @@ void test_emplaceable_concept() {
 
 
 
-int main()
+int main(int, char**)
 {
     test_emplaceable_concept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_move.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_move.pass.cpp
index 1a915060c1a..4b70c7843f1 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_move.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<MoveOnly, test_allocator<MoveOnly> > l(test_allocator<MoveOnly>(5));
@@ -95,4 +95,6 @@ int main()
         assert(l2.get_allocator() == lo.get_allocator());
         assert(is_contiguous_container_asan_correct(l2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_size_value.pass.cpp
index 4f053072234..b85238db9a9 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_size_value.pass.cpp
@@ -29,7 +29,7 @@ void test ( Vec &v )
     assert(std::all_of(v.begin(), v.end(), is6));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<int> V;
@@ -50,4 +50,6 @@ int main()
     test(d2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_default.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_default.pass.cpp
index c31b3c2faa5..346c357d3f3 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_default.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_default.pass.cpp
@@ -60,7 +60,7 @@ test1(const typename C::allocator_type& a)
     LIBCPP_ASSERT(is_contiguous_container_asan_correct(c));
 }
 
-int main()
+int main(int, char**)
 {
     {
     test0<std::vector<int> >();
@@ -98,4 +98,6 @@ int main()
         assert(v.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp
index 1623c8296be..8f8ffa82c0c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp
@@ -176,9 +176,11 @@ void test_ctor_with_different_value_type() {
 }
 
 
-int main() {
+int main(int, char**) {
   basic_test_cases();
   emplaceable_concept_tests(); // See PR34898
   test_ctor_under_alloc();
   test_ctor_with_different_value_type();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
index 6cd319bc8a9..3a97b43b7e0 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
@@ -162,8 +162,10 @@ void test_ctor_under_alloc() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   basic_tests();
   emplaceable_concept_tests(); // See PR34898
   test_ctor_under_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size.pass.cpp
index fe20a703694..f111220d3a4 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size.pass.cpp
@@ -60,7 +60,7 @@ test(typename C::size_type n)
     test2<C> ( n );
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >(50);
     test<std::vector<DefaultOnly> >(500);
@@ -71,4 +71,6 @@ int main()
     test2<std::vector<DefaultOnly, test_allocator<DefaultOnly>> >( 100, test_allocator<DefaultOnly>(23));
     assert(DefaultOnly::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value.pass.cpp
index c8cd2f2a3c4..0839883a9b5 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value.pass.cpp
@@ -30,7 +30,7 @@ test(typename C::size_type n, const typename C::value_type& x)
         assert(*i == x);
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >(50, 3);
     // Add 1 for implementations that dynamically allocate a container proxy.
@@ -38,4 +38,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<std::vector<int, min_allocator<int>> >(50, 3);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value_alloc.pass.cpp
index c0bba42da45..1de08853454 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/construct_size_value_alloc.pass.cpp
@@ -31,10 +31,12 @@ test(typename C::size_type n, const typename C::value_type& x,
         assert(*i == x);
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >(50, 3, std::allocator<int>());
 #if TEST_STD_VER >= 11
     test<std::vector<int, min_allocator<int>> >(50, 3, min_allocator<int>());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/copy.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/copy.pass.cpp
index 1542827e35b..844da38416b 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/copy.pass.cpp
@@ -30,7 +30,7 @@ test(const C& x)
     LIBCPP_ASSERT(is_contiguous_container_asan_correct(c));
 }
 
-int main()
+int main(int, char**)
 {
     {
         int a[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 1, 0};
@@ -74,4 +74,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/copy_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/copy_alloc.pass.cpp
index d54fc59f508..79b484f78c7 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/copy_alloc.pass.cpp
@@ -30,7 +30,7 @@ test(const C& x, const typename C::allocator_type& a)
     LIBCPP_ASSERT(is_contiguous_container_asan_correct(c));
 }
 
-int main()
+int main(int, char**)
 {
     {
         int a[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 1, 0};
@@ -62,4 +62,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<int>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.fail.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.fail.cpp
index 0ce0bafbff4..beb10498c77 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.fail.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.fail.cpp
@@ -23,7 +23,7 @@
 #include <cstddef>
 
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
 
@@ -36,4 +36,6 @@ int main()
 //      deque<allocator<int>, allocator<allocator<int>>>
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.pass.cpp
index 0ada98c0c9a..e6b59b40c8f 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/deduct.pass.cpp
@@ -29,7 +29,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -112,4 +112,6 @@ int main()
     static_assert(std::is_same_v<decltype(vec)::allocator_type, std::allocator<bool>>, "");
     assert(vec.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/default.recursive.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/default.recursive.pass.cpp
index e7298ba85a0..1558ea4b619 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/default.recursive.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/default.recursive.pass.cpp
@@ -17,6 +17,8 @@ struct X
     std::vector<X> q;
 };
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/default_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/default_noexcept.pass.cpp
index 24f78b28244..91434964b2c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/default_noexcept.pass.cpp
@@ -29,7 +29,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         typedef std::vector<MoveOnly, some_alloc<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/dtor_noexcept.pass.cpp
index e02a7b029e2..f4c05b6e2d5 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/dtor_noexcept.pass.cpp
@@ -27,7 +27,7 @@ struct some_alloc
     ~some_alloc() noexcept(false);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<MoveOnly> C;
@@ -47,4 +47,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list.pass.cpp
index a839e03666a..168e3b58bd5 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<int> d = {3, 4, 5, 6};
@@ -37,4 +37,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list_alloc.pass.cpp
index f8ea034f740..633b5c5e2ea 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/initializer_list_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<int, test_allocator<int>> d({3, 4, 5, 6}, test_allocator<int>(3));
@@ -41,4 +41,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/move.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/move.pass.cpp
index e5d625b5e36..938857458b7 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/move.pass.cpp
@@ -21,7 +21,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<MoveOnly, test_allocator<MoveOnly> > l(test_allocator<MoveOnly>(5));
@@ -129,4 +129,6 @@ int main()
         assert(a.get_data() == 42);
       }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/move_alloc.pass.cpp
index dcea27a0d7a..2f15a14e8c8 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/move_alloc.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<MoveOnly, test_allocator<MoveOnly> > l(test_allocator<MoveOnly>(5));
@@ -93,4 +93,6 @@ int main()
         assert(l2.get_allocator() == min_allocator<MoveOnly>());
         assert(is_contiguous_container_asan_correct(l2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/move_assign_noexcept.pass.cpp
index 8eeb19eb43a..c5c5e29cda4 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/move_assign_noexcept.pass.cpp
@@ -57,7 +57,7 @@ struct some_alloc3
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<MoveOnly> C;
@@ -91,4 +91,6 @@ int main()
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/move_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/move_noexcept.pass.cpp
index a9a554ad213..1228414289f 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/move_noexcept.pass.cpp
@@ -28,7 +28,7 @@ struct some_alloc
     some_alloc(const some_alloc&);
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<MoveOnly> C;
@@ -51,4 +51,6 @@ int main()
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/op_equal_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/op_equal_initializer_list.pass.cpp
index 941f1e012b3..61c20b7c7f0 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/op_equal_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/op_equal_initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<int> d;
@@ -40,4 +40,6 @@ int main()
     assert(d[2] == 5);
     assert(d[3] == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.data/data.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.data/data.pass.cpp
index cd176c7017b..3477c5eb1bd 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.data/data.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.data/data.pass.cpp
@@ -25,7 +25,7 @@ struct Nasty {
     int i_;
     };
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v;
@@ -59,4 +59,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.data/data_const.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.data/data_const.pass.cpp
index 33d973954e2..ec5016d2f6c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.data/data_const.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.data/data_const.pass.cpp
@@ -25,7 +25,7 @@ struct Nasty {
     int i_;
     };
 
-int main()
+int main(int, char**)
 {
     {
         const std::vector<int> v;
@@ -59,4 +59,6 @@ int main()
         assert(is_contiguous_container_asan_correct(v));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.erasure/erase.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.erasure/erase.pass.cpp
index 3a96b55cadf..00676b52dc6 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.erasure/erase.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.erasure/erase.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,1}), opt(3), S({1,2,1}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int>>();
     test<std::vector<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::vector<long>>();
     test<std::vector<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.erasure/erase_if.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.erasure/erase_if.pass.cpp
index f18c4048377..10d66a29b4e 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.erasure/erase_if.pass.cpp
@@ -66,7 +66,7 @@ void test()
     test0(S({1,2,3}), False, S({1,2,3}));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int>>();
     test<std::vector<int, min_allocator<int>>> ();
@@ -74,4 +74,6 @@ int main()
 
     test<std::vector<long>>();
     test<std::vector<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/clear.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/clear.pass.cpp
index a1ce8f00026..334c67adcfc 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/clear.pass.cpp
@@ -17,7 +17,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
     int a[] = {1, 2, 3};
@@ -39,4 +39,6 @@ int main()
     LIBCPP_ASSERT(is_contiguous_container_asan_correct(c));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace.pass.cpp
index 7acc90b5a69..1279fba4ce2 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace.pass.cpp
@@ -52,7 +52,7 @@ public:
     double getd() const {return d_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<A> c;
@@ -132,4 +132,6 @@ int main()
         assert(c.back().geti() == 3);
         assert(c.back().getd() == 4.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_back.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_back.pass.cpp
index 6ddc88560d2..435be207bb4 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_back.pass.cpp
@@ -53,7 +53,7 @@ public:
     double getd() const {return d_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<A> c;
@@ -144,4 +144,6 @@ int main()
         assert(c.size() == 2);
         assert(is_contiguous_container_asan_correct(c));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp
index 45835c33862..ec5f778565a 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp
@@ -18,7 +18,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v;
@@ -56,4 +56,6 @@ int main()
         assert(v[0] == 3);
         assert(is_contiguous_container_asan_correct(v));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter.pass.cpp
index def3b350dd2..aac35f9f811 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter.pass.cpp
@@ -32,7 +32,7 @@ struct Throws {
 bool Throws::sThrows = false;
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -99,4 +99,6 @@ int main()
     assert(v.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter_iter.pass.cpp
index aab348f08bf..7682000d75e 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/erase_iter_iter.pass.cpp
@@ -32,7 +32,7 @@ struct Throws {
 bool Throws::sThrows = false;
 #endif
 
-int main()
+int main(int, char**)
 {
     int a1[] = {1, 2, 3};
     {
@@ -152,4 +152,6 @@ int main()
     assert(v.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_initializer_list.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_initializer_list.pass.cpp
index 46b6c010abf..30d0cd686a4 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::vector<int> d(10, 1);
@@ -62,4 +62,6 @@ int main()
     assert(d[12] == 1);
     assert(d[13] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_iter_iter.pass.cpp
index fadd09e3e5a..74cb612aab0 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_iter_iter.pass.cpp
@@ -21,7 +21,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<int> V;
@@ -171,4 +171,6 @@ int main()
             assert(v[j] == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_rvalue.pass.cpp
index e2190fd885d..780bd9c485f 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_rvalue.pass.cpp
@@ -21,7 +21,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<MoveOnly> v(100);
@@ -62,4 +62,6 @@ int main()
         for (++j; j < 101; ++j)
             assert(v[j] == MoveOnly());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_size_value.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_size_value.pass.cpp
index ddaa4fb6a35..5b182f44d6a 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_size_value.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v(100);
@@ -111,4 +111,6 @@ int main()
             assert(v[j] == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_value.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_value.pass.cpp
index 23f0030ab25..2edadd0fe77 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_iter_value.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> v(100);
@@ -93,4 +93,6 @@ int main()
             assert(v[j] == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/pop_back.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/pop_back.pass.cpp
index c0784f7031e..db2337c276e 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/pop_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/pop_back.pass.cpp
@@ -18,7 +18,7 @@
 #include "min_allocator.h"
 
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> c;
@@ -37,4 +37,6 @@ int main()
         assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back.pass.cpp
index e9bcf24116b..d22136ddbcb 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back.pass.cpp
@@ -17,7 +17,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<int> c;
@@ -108,4 +108,6 @@ int main()
             assert(c[j] == j);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_exception_safety.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_exception_safety.pass.cpp
index 48152cb81cf..9e25611290c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_exception_safety.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_exception_safety.pass.cpp
@@ -64,7 +64,7 @@ CMyClass::~CMyClass() {
 
 bool operator==(const CMyClass &lhs, const CMyClass &rhs) { return lhs.equal(rhs); }
 
-int main()
+int main(int, char**)
 {
     CMyClass instance(42);
     std::vector<CMyClass> vec;
@@ -85,4 +85,6 @@ int main()
         assert(is_contiguous_container_asan_correct(vec));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_rvalue.pass.cpp
index 070cabe5c29..d876eb6170a 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.modifiers/push_back_rvalue.pass.cpp
@@ -20,7 +20,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::vector<MoveOnly> c;
@@ -109,4 +109,6 @@ int main()
         for (int j = 0; static_cast<std::size_t>(j) < c.size(); ++j)
             assert(c[j] == MoveOnly(j));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.special/swap.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.special/swap.pass.cpp
index d107be98fb5..2ded4fe750f 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.special/swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.special/swap.pass.cpp
@@ -18,7 +18,7 @@
 #include "min_allocator.h"
 #include "asan_testing.h"
 
-int main()
+int main(int, char**)
 {
     {
         int a1[] = {1, 3, 7, 9, 10};
@@ -178,4 +178,6 @@ int main()
         assert(is_contiguous_container_asan_correct(c2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp
index 06d89282f2a..40205b67c3c 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp
@@ -53,7 +53,7 @@ struct some_alloc2
     typedef std::true_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::vector<MoveOnly> C;
@@ -85,4 +85,6 @@ int main()
         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/iterator_difference_type.pass.cpp b/libcxx/test/std/containers/unord/iterator_difference_type.pass.cpp
index 3f0b61e5f22..fc5ccbee34f 100644
--- a/libcxx/test/std/containers/unord/iterator_difference_type.pass.cpp
+++ b/libcxx/test/std/containers/unord/iterator_difference_type.pass.cpp
@@ -73,7 +73,7 @@ void testUnorderedSet() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef std::unordered_map<int, int> Map;
     typedef std::pair<const int, int> ValueTp;
@@ -150,4 +150,6 @@ int main() {
     testUnorderedSet<Set, ValueTp, min_pointer<const ValueTp>>();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/unord/unord.map/allocator_mismatch.fail.cpp
index 9dc9869eaf7..7059220425d 100644
--- a/libcxx/test/std/containers/unord/unord.map/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <unordered_map>
 
-int main()
+int main(int, char**)
 {
     std::unordered_map<int, int, std::hash<int>, std::less<int>, std::allocator<long> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp b/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp
index ae65ac88795..522b7097650 100644
--- a/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -74,4 +74,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp
index b2529a831ad..ee1a125232b 100644
--- a/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -71,4 +71,6 @@ int main()
         assert(c.bucket_count() >= 8);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp
index 2edb6cc206c..439d2b533bf 100644
--- a/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -78,4 +78,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/compare.pass.cpp b/libcxx/test/std/containers/unord/unord.map/compare.pass.cpp
index 6c5891e1a8d..7d6cbf9a8ad 100644
--- a/libcxx/test/std/containers/unord/unord.map/compare.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/compare.pass.cpp
@@ -32,7 +32,7 @@ namespace std
     };
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::unordered_map<Key, int> MapT;
     typedef MapT::iterator Iter;
@@ -42,4 +42,6 @@ int main()
     std::pair<Iter, bool> result = map.insert(std::make_pair(Key(0), 42));
     assert(result.second);
     assert(result.first->second == 42);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/count.pass.cpp b/libcxx/test/std/containers/unord/unord.map/count.pass.cpp
index bd754843cad..1a1bea90b82 100644
--- a/libcxx/test/std/containers/unord/unord.map/count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/count.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -61,4 +61,6 @@ int main()
         assert(c.count(5) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/empty.fail.cpp b/libcxx/test/std/containers/unord/unord.map/empty.fail.cpp
index c4fa89e662d..283d6fa3e24 100644
--- a/libcxx/test/std/containers/unord/unord.map/empty.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::unordered_map<int, int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/empty.pass.cpp b/libcxx/test/std/containers/unord/unord.map/empty.pass.cpp
index 1dcba5cf70f..da6d48df2d5 100644
--- a/libcxx/test/std/containers/unord/unord.map/empty.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_map<int, double> M;
@@ -42,4 +42,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp b/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp
index 99bd1fa6758..d284e822ade 100644
--- a/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -159,4 +159,6 @@ int main()
         assert(!(c1 != c2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp
index a3b2b5c8a97..b9dd9a64e2e 100644
--- a/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -71,4 +71,6 @@ int main()
         assert(std::distance(r.first, r.second) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp
index 505d355d7a3..029222d5caf 100644
--- a/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -71,4 +71,6 @@ int main()
         assert(std::distance(r.first, r.second) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/erase_if.pass.cpp b/libcxx/test/std/containers/unord/unord.map/erase_if.pass.cpp
index 5238d9ee0e8..5498f454388 100644
--- a/libcxx/test/std/containers/unord/unord.map/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/erase_if.pass.cpp
@@ -67,7 +67,7 @@ void test()
     test0<S>({1,2,3}, False, {1,2,3});
 }
 
-int main()
+int main(int, char**)
 {
     test<std::unordered_map<int, int>>();
     test<std::unordered_map<int, int, std::hash<int>, std::equal_to<int>, min_allocator<std::pair<const int, int>>>> ();
@@ -75,5 +75,7 @@ int main()
 
     test<std::unordered_map<long, short>>();
     test<std::unordered_map<short, double>>();
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp
index 65c2a12088f..1d63b4be2ef 100644
--- a/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(i == c.cend());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp
index e6efa8e0642..58a9cd35afd 100644
--- a/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(i == c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/incomplete_type.pass.cpp b/libcxx/test/std/containers/unord/unord.map/incomplete_type.pass.cpp
index f6faaac500e..ddcd6e14c50 100644
--- a/libcxx/test/std/containers/unord/unord.map/incomplete_type.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/incomplete_type.pass.cpp
@@ -31,6 +31,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.map/iterators.pass.cpp
index 609e7d7c4af..0b4e02e339f 100644
--- a/libcxx/test/std/containers/unord/unord.map/iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/iterators.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -126,4 +126,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp
index 418cdf7fd5f..7a5fde8a489 100644
--- a/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -73,4 +73,6 @@ int main()
         assert(c.load_factor() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/local_iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.map/local_iterators.pass.cpp
index f51df487856..e24e1811ac1 100644
--- a/libcxx/test/std/containers/unord/unord.map/local_iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/local_iterators.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -417,4 +417,6 @@ int main()
         assert(i->second == "four");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/max_bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.map/max_bucket_count.pass.cpp
index d9c03128a3a..eb8f3e9d2ed 100644
--- a/libcxx/test/std/containers/unord/unord.map/max_bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/max_bucket_count.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -36,4 +36,6 @@ int main()
         assert(c.max_bucket_count() > 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/max_load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.map/max_load_factor.pass.cpp
index e57eb71d32a..8620dd1bd46 100644
--- a/libcxx/test/std/containers/unord/unord.map/max_load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/max_load_factor.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -65,4 +65,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/max_size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/max_size.pass.cpp
index 3dc62d0b8aa..7c2ec58de57 100644
--- a/libcxx/test/std/containers/unord/unord.map/max_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   typedef std::pair<const int, int> KV;
   {
@@ -49,4 +49,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/rehash.pass.cpp b/libcxx/test/std/containers/unord/unord.map/rehash.pass.cpp
index ff7b1b75f22..c8f079fb617 100644
--- a/libcxx/test/std/containers/unord/unord.map/rehash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/rehash.pass.cpp
@@ -37,7 +37,7 @@ void test(const C& c)
     assert(c.at(4) == "four");
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -100,4 +100,6 @@ int main()
         test(c);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/reserve.pass.cpp b/libcxx/test/std/containers/unord/unord.map/reserve.pass.cpp
index 983c872379a..622a9691e45 100644
--- a/libcxx/test/std/containers/unord/unord.map/reserve.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/reserve.pass.cpp
@@ -46,7 +46,7 @@ void reserve_invariant(size_t n) // LWG #2156
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -104,4 +104,6 @@ int main()
     }
 #endif
     reserve_invariant(20);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/size.pass.cpp
index 22a922d1fbe..d4e7cb97f64 100644
--- a/libcxx/test/std/containers/unord/unord.map/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_map<int, double> M;
@@ -58,4 +58,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp b/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp
index 2763940f8c5..ff9b32e3ea2 100644
--- a/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -567,4 +567,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/types.pass.cpp b/libcxx/test/std/containers/unord/unord.map/types.pass.cpp
index 1c8c86b5d93..e194f69f8ac 100644
--- a/libcxx/test/std/containers/unord/unord.map/types.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/types.pass.cpp
@@ -32,7 +32,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<char, short> C;
@@ -68,4 +68,6 @@ int main()
         static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/allocator.pass.cpp
index 0c1ee685b52..8f1d7561b24 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -126,4 +126,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_copy.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_copy.pass.cpp
index 2820e66a82f..a5a67bcc29d 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_copy.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<std::pair<const int, std::string> > A;
@@ -185,4 +185,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_init.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_init.pass.cpp
index 8f651b92983..e9e62898886 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_init.pass.cpp
@@ -27,7 +27,7 @@
 #include "../../../test_hash.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::allocator<std::pair<const int, std::string> > A;
@@ -93,4 +93,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_move.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_move.pass.cpp
index ab0df753a31..87b80cef1c4 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/assign_move.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<std::pair<const int, std::string> > A;
@@ -214,4 +214,6 @@ int main()
         assert(c.max_load_factor() == 1);
         assert(c0.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/compare_copy_constructible.fail.cpp
index 1a3cbc38668..2591c99f4e4 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/compare_copy_constructible.fail.cpp
@@ -26,6 +26,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_map<int, int, std::hash<int>, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy.pass.cpp
index c8e1d73d0ff..ee4bc43a54a 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -148,4 +148,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy_alloc.pass.cpp
index 939e30c8211..8e7a3a0796e 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/copy_alloc.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -148,4 +148,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default.pass.cpp
index fe95ce8f865..bda7d24a6fd 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -108,4 +108,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default_noexcept.pass.cpp
index cf00bb116be..a4af74a89a1 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/default_noexcept.pass.cpp
@@ -45,7 +45,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -72,4 +72,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/dtor_noexcept.pass.cpp
index 247e57600d6..4f4331fa087 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/dtor_noexcept.pass.cpp
@@ -38,7 +38,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<MoveOnly, MoveOnly> C;
@@ -65,4 +65,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/hash_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/hash_copy_constructible.fail.cpp
index 3da62824078..026e319fcbd 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/hash_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/hash_copy_constructible.fail.cpp
@@ -26,6 +26,8 @@ private:
 };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_map<int, int, Hash<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init.pass.cpp
index 6b00cb7c515..00b4a2f0bc2 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -159,4 +159,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size.pass.cpp
index 702b9231ea2..f1dbad9feca 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -97,4 +97,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash.pass.cpp
index 57f6dca546d..c0c3d5c5b8a 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -99,4 +99,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal.pass.cpp
index d8d073a4d55..5c87af0a1e0 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -102,4 +102,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal_allocator.pass.cpp
index 0bce91b3ac4..5ab0366da29 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/init_size_hash_equal_allocator.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -140,4 +140,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move.pass.cpp
index fdcd596e939..d4eed3c03be 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -176,4 +176,6 @@ int main()
         assert(s2.size() == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_alloc.pass.cpp
index 82e83ba482b..be72227dabe 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_alloc.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, std::string> P;
@@ -195,4 +195,6 @@ int main()
 
         assert(c0.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_assign_noexcept.pass.cpp
index 71e913f2756..78ac7d787c2 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_assign_noexcept.pass.cpp
@@ -44,7 +44,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<MoveOnly, MoveOnly> C;
@@ -71,4 +71,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_noexcept.pass.cpp
index 09fefc4baf4..62175145de9 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/move_noexcept.pass.cpp
@@ -41,7 +41,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -68,4 +68,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range.pass.cpp
index 002a39a861c..a6d87150846 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -169,4 +169,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size.pass.cpp
index e9ce1a29f2d..66e0ac3a769 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -104,4 +104,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash.pass.cpp
index 5240d2b5246..62a590736bf 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash.pass.cpp
@@ -31,7 +31,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -107,4 +107,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal.pass.cpp
index a8f69b235c9..70e391d4663 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal.pass.cpp
@@ -31,7 +31,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -109,4 +109,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal_allocator.pass.cpp
index 9c8f221f306..1f29c5414ea 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/range_size_hash_equal_allocator.pass.cpp
@@ -32,7 +32,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string,
@@ -150,4 +150,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.fail.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.fail.cpp
index 50252dd5b88..9a715b6a1bb 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.fail.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -66,4 +66,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.pass.cpp
index d9af5a3226e..41cfc7104fa 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -66,4 +66,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash.pass.cpp
index 2c69847d90b..f97ee39fbef 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -70,4 +70,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal.pass.cpp
index b47f309f9d6..8c306364ed8 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -72,4 +72,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal_allocator.pass.cpp
index 1e821b8c668..40b9d01a203 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/size_hash_equal_allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<NotConstructible, NotConstructible,
@@ -96,4 +96,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.elem/at.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.elem/at.pass.cpp
index 11db9bff726..fe6ef8bc7e8 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.elem/at.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.elem/at.pass.cpp
@@ -24,7 +24,7 @@
 #include "min_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -140,4 +140,6 @@ int main()
 #endif
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index.pass.cpp
index 4ddb9f986a7..ff83f1d6842 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index.pass.cpp
@@ -28,7 +28,7 @@
 #include "container_test_types.h"
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -159,4 +159,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index_tuple.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index_tuple.pass.cpp
index feea53ecdab..4719b5583b3 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index_tuple.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.elem/index_tuple.pass.cpp
@@ -28,8 +28,10 @@ struct my_hash
     size_t operator()(const tuple<int,int>&) const {return 0;}
 };
 
-int main()
+int main(int, char**)
 {
     unordered_map<tuple<int,int>, size_t, my_hash> m;
     m[make_tuple(2,3)]=7;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/clear.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/clear.pass.cpp
index 6b0f03d9c28..64fe72ecdac 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/clear.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -60,4 +60,6 @@ int main()
         assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace.pass.cpp
index 2ea264b5343..63a269601f0 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace.pass.cpp
@@ -23,7 +23,7 @@
 #include "../../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, Emplaceable> C;
@@ -74,4 +74,6 @@ int main()
         assert(r.first->first == 5);
         assert(r.first->second == Emplaceable(6, 7));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace_hint.pass.cpp
index a130d65c0ce..01e8d9c6fab 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/emplace_hint.pass.cpp
@@ -24,7 +24,7 @@
 #include "../../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, Emplaceable> C;
@@ -71,4 +71,6 @@ int main()
         assert(r->first == 5);
         assert(r->second == Emplaceable(6, 7));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_const_iter.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_const_iter.pass.cpp
index 78e70fbba4b..1d0b18bf1d4 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_const_iter.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_const_iter.pass.cpp
@@ -30,7 +30,7 @@ struct TemplateConstructor
 bool operator==(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 struct Hash { size_t operator() (const TemplateConstructor &) const { return 0; } };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -89,4 +89,6 @@ int main()
             m.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db1.pass.cpp
index b923752ef58..38ba03d5e88 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db1.pass.cpp
@@ -17,7 +17,7 @@
 #include <unordered_map>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -31,8 +31,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db2.pass.cpp
index fcc499ebf8f..887f7859b3e 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <cstdlib>
 #include <exception>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -34,8 +34,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db1.pass.cpp
index fd9931ad2a0..15c6745adc9 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db1.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db2.pass.cpp
index 9f64445af0b..0ae0674adb7 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db3.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db3.pass.cpp
index 16cf5367fd4..134d075ec6e 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db3.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db3.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db4.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db4.pass.cpp
index 2c59093458f..17745175bae 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db4.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db4.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_key.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_key.pass.cpp
index aa2dea3d9ed..305d149a583 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_key.pass.cpp
@@ -38,7 +38,7 @@ bool only_deletions ( const Unordered &whole, const Unordered &part ) {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -174,4 +174,6 @@ int main()
     assert (only_deletions (m, m2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp
index 5c2c676f2fb..839d65733de 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -95,4 +95,6 @@ int main()
         assert(k == c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_iterator.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_iterator.pass.cpp
index 332eea13fb6..3ad30510f92 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_iterator.pass.cpp
@@ -40,7 +40,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using map_type = std::unordered_map<int, int>;
@@ -63,4 +63,6 @@ int main()
         min_alloc_map m = {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {5, 5}, {6, 6}};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp
index 3272a438393..4d6c24e6e99 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp
@@ -45,7 +45,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_map<int, int> m = {{1,1}, {2,2}, {3,3}, {4,4}, {5,5}, {6,6}};
@@ -72,4 +72,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp
index f84e98c2bab..71d456e6619 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_and_emplace_allocator_requirements.pass.cpp
@@ -21,10 +21,12 @@
 #include "container_test_types.h"
 #include "../../../map_allocator_requirement_test_templates.h"
 
-int main()
+int main(int, char**)
 {
   testMapInsert<TCT::unordered_map<> >();
   testMapInsertHint<TCT::unordered_map<> >();
   testMapEmplace<TCT::unordered_map<> >();
   testMapEmplaceHint<TCT::unordered_map<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_const_lvalue.pass.cpp
index 3b4b7db1daf..eb505218fdd 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_const_lvalue.pass.cpp
@@ -65,7 +65,7 @@ void do_insert_cv_test()
     assert(r.first->second == 3);
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<double, int> M;
@@ -78,4 +78,6 @@ int main()
         do_insert_cv_test<M>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_const_lvalue.pass.cpp
index 60c5d359c73..b1b77eb9c18 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_const_lvalue.pass.cpp
@@ -56,7 +56,7 @@ void do_insert_hint_const_lvalue_test()
     assert(r->second == 4);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_hint_const_lvalue_test<std::unordered_map<double, int> >();
 #if TEST_STD_VER >= 11
@@ -80,4 +80,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_rvalue.pass.cpp
index 4670fbfbed8..b7374d1a6ee 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_hint_rvalue.pass.cpp
@@ -28,7 +28,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<double, int> C;
@@ -173,4 +173,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_init.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_init.pass.cpp
index 20b5fb649c8..27e8747348e 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_init.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -66,4 +66,6 @@ int main()
         assert(c.at(3) == "three");
         assert(c.at(4) == "four");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type.pass.cpp
index 5840950d7a2..24d0a23a59f 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type.pass.cpp
@@ -74,10 +74,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_map<int, int> m;
     test(m);
     std::unordered_map<int, int, std::hash<int>, std::equal_to<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type_hint.pass.cpp
index 3a97868804a..21ccb88caf0 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_node_type_hint.pass.cpp
@@ -54,10 +54,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_map<int, int> m;
     test(m);
     std::unordered_map<int, int, std::hash<int>, std::equal_to<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp
index 5c02fc1290d..7fc3ff187be 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp
@@ -61,7 +61,7 @@ namespace std {
     };
 }
 
-int main()
+int main(int, char**)
 {
 
     { // pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);
@@ -188,4 +188,6 @@ int main()
         assert(r->second.get() == 5);  // value
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_range.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_range.pass.cpp
index a70703b5fa6..1d51bdb4fbc 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_range.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(c.at(4) == "four");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_rvalue.pass.cpp
index ed0a2a58df8..1f8528ab5b1 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_rvalue.pass.cpp
@@ -24,7 +24,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_map<double, int> C;
@@ -172,4 +172,6 @@ int main()
         assert(r.first->first == 5.5);
         assert(r.first->second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/merge.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/merge.pass.cpp
index 17be66154a1..1437d46d2e2 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/merge.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_hasher
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_map<int, int> src{{1, 0}, {3, 0}, {5, 0}};
@@ -153,4 +153,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp
index dbdb1b89bf6..c3ee0050a26 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp
@@ -60,7 +60,7 @@ namespace std {
     };
 }
 
-int main()
+int main(int, char**)
 {
 
     { // pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);
@@ -185,4 +185,6 @@ int main()
         assert(r->first.get()  == 3); // key
         assert(r->second.get() == 4); // value
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/db_swap_1.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/db_swap_1.pass.cpp
index e47e7b6600f..67a49d4bb8b 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/db_swap_1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/db_swap_1.pass.cpp
@@ -21,7 +21,7 @@
 #include <unordered_map>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if _LIBCPP_DEBUG >= 1
     {
@@ -40,4 +40,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp
index 2522270fd7a..44ee7be490d 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp
@@ -119,7 +119,7 @@ struct some_alloc3
 };
 
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> MapType;
     {
@@ -188,4 +188,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_non_member.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_non_member.pass.cpp
index 9966bcd4f9d..7852394cdfb 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_non_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_non_member.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -567,4 +567,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/allocator_mismatch.fail.cpp
index f1e7a2a96f5..ba24ca3cc95 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <unordered_map>
 
-int main()
+int main(int, char**)
 {
     std::unordered_multimap<int, int, std::hash<int>, std::less<int>, std::allocator<long> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp
index 7b10eb86beb..c6c8b217cc4 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -74,4 +74,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp
index 340c1dcc2c2..9c073571909 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -44,4 +44,6 @@ int main()
         const C c(std::begin(a), std::end(a));
         assert(c.bucket_count() >= 8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp
index b7c7d653f5f..f4919752153 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -82,4 +82,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp
index 15134dd0f22..4a6ec5d6576 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(c.count(5) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/db_iterators_7.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/db_iterators_7.pass.cpp
index 2cffa13a4e0..463b49938ef 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/db_iterators_7.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/db_iterators_7.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multimap<int, std::string> C;
@@ -52,8 +52,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/db_iterators_8.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/db_iterators_8.pass.cpp
index 62da82f2d10..38395e5f960 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/db_iterators_8.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/db_iterators_8.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multimap<int, std::string> C;
@@ -48,8 +48,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_7.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_7.pass.cpp
index a609b5dd0cc..04d8b3ff06c 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_7.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_7.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multimap<int, std::string> C;
@@ -49,8 +49,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_8.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_8.pass.cpp
index a397cad563e..69ef06993dc 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_8.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/db_local_iterators_8.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multimap<int, std::string> C;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/empty.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/empty.fail.cpp
index 93ec56e94f7..4eb7bfc9c36 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/empty.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::unordered_multimap<int, int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/empty.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/empty.pass.cpp
index 58f4e602f9b..6189b7f0e3d 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/empty.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multimap<int, double> M;
@@ -42,4 +42,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp
index 85dfb00923d..5751916875f 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -177,4 +177,6 @@ int main()
         assert(!(c1 != c2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp
index 88686a1fd3b..148081be7be 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -100,4 +100,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp
index 5e833c978ad..5da87166bda 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -100,4 +100,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/erase_if.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/erase_if.pass.cpp
index ef44cd81bf8..2cec092056d 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/erase_if.pass.cpp
@@ -78,7 +78,7 @@ void test()
     test0<S>({1,2,3}, False, {1,2,3});
 }
 
-int main()
+int main(int, char**)
 {
     test<std::unordered_multimap<int, int>>();
     test<std::unordered_multimap<int, int, std::hash<int>, std::equal_to<int>, min_allocator<std::pair<const int, int>>>> ();
@@ -86,4 +86,6 @@ int main()
 
     test<std::unordered_multimap<long, short>>();
     test<std::unordered_multimap<short, double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp
index c48d6ffff1d..271bf9d0c60 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(i == c.cend());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp
index b8975ef09ac..3e642e346f1 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(i == c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/incomplete.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/incomplete.pass.cpp
index 77f03f51fc7..6ea4931299b 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/incomplete.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/incomplete.pass.cpp
@@ -31,6 +31,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/iterators.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/iterators.fail.cpp
index aed2f713879..0c1b50fac05 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/iterators.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/iterators.fail.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -67,4 +67,6 @@ int main()
         assert(std::distance(c.begin(), c.end()) == c.size());
         assert(std::distance(c.cbegin(), c.cend()) == c.size());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/iterators.pass.cpp
index e669be6f3b8..5fd52beebbc 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/iterators.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -132,4 +132,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp
index f1624616ec4..ae8a8403b85 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -72,4 +72,6 @@ int main()
         assert(c.load_factor() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/local_iterators.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/local_iterators.fail.cpp
index 313c9e3782d..f5af791804b 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/local_iterators.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/local_iterators.fail.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -284,4 +284,6 @@ int main()
         j = c.cend(b);
         assert(std::distance(i, j) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/local_iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/local_iterators.pass.cpp
index 61815a9c673..b5dd2d4b0fd 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/local_iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/local_iterators.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -658,4 +658,6 @@ int main()
         assert(std::distance(i, j) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/max_bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/max_bucket_count.pass.cpp
index b2442ff8725..c55f4de8d44 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/max_bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/max_bucket_count.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -35,4 +35,6 @@ int main()
         assert(c.max_bucket_count() > 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/max_load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/max_load_factor.pass.cpp
index a75052ebdb1..ed46b681b7d 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/max_load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/max_load_factor.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -63,4 +63,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/max_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/max_size.pass.cpp
index 5ed732902bf..d03cf67ae7c 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/max_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   typedef std::pair<const int, int> KV;
   {
@@ -51,4 +51,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/rehash.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/rehash.pass.cpp
index aa8996a1a7a..99538e32d82 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/rehash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/rehash.pass.cpp
@@ -81,7 +81,7 @@ void test(const C& c)
     assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -144,4 +144,6 @@ int main()
         test(c);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/reserve.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/reserve.pass.cpp
index 1771faa60c4..811ac97fb4a 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/reserve.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/reserve.pass.cpp
@@ -61,7 +61,7 @@ void reserve_invariant(size_t n) // LWG #2156
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -119,4 +119,6 @@ int main()
     }
 #endif
     reserve_invariant(20);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/scary.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/scary.pass.cpp
index 321c38ceb26..4c4b1cd110e 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/scary.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/scary.pass.cpp
@@ -14,11 +14,13 @@
 
 #include <unordered_map>
 
-int main()
+int main(int, char**)
 {
     typedef std::unordered_map<int, int> M1;
     typedef std::unordered_multimap<int, int> M2;
     M2::iterator i;
     M1::iterator j = i;
     ((void)j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/size.pass.cpp
index c24d93b5bfc..493b8d757cf 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multimap<int, double> M;
@@ -58,4 +58,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp
index f57d821094f..75806df9791 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -653,4 +653,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/types.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/types.pass.cpp
index 5e7e1451b37..2cb74a1545d 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/types.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/types.pass.cpp
@@ -32,7 +32,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<char, short> C;
@@ -68,4 +68,6 @@ int main()
         static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/allocator.pass.cpp
index dadd81765a9..e15999f183e 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -126,4 +126,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_copy.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_copy.pass.cpp
index 3b2b0cba703..191dec98e58 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_copy.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<std::pair<const int, std::string> > A;
@@ -227,4 +227,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_init.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_init.pass.cpp
index cae8605dbb2..5947905a62e 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_init.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<std::pair<const int, std::string> > A;
@@ -142,4 +142,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_move.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_move.pass.cpp
index f918721113d..21c791a814f 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/assign_move.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<std::pair<const int, std::string> > A;
@@ -291,4 +291,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/compare_copy_constructible.fail.cpp
index 7438bf5301c..fe288035fd0 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/compare_copy_constructible.fail.cpp
@@ -26,6 +26,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_multimap<int, int, std::hash<int>, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy.pass.cpp
index 7747aef541d..d570162222f 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -190,4 +190,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy_alloc.pass.cpp
index 41b5f537d99..ebd04718484 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/copy_alloc.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -190,4 +190,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default.pass.cpp
index 3cd4da37e1e..dea7a460438 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -108,4 +108,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default_noexcept.pass.cpp
index 4866dde5d86..5a54f61b503 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/default_noexcept.pass.cpp
@@ -44,7 +44,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -71,4 +71,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/dtor_noexcept.pass.cpp
index f276bf77731..8f677edcb9c 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/dtor_noexcept.pass.cpp
@@ -37,7 +37,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly> C;
@@ -64,4 +64,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/hash_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/hash_copy_constructible.fail.cpp
index f6b8cb23e18..2681710c94d 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/hash_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/hash_copy_constructible.fail.cpp
@@ -26,6 +26,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_multimap<int, int, Hash<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init.pass.cpp
index 43fb0f971cc..aba32bfeb84 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -251,4 +251,6 @@ int main()
         assert(!(c.get_allocator() == A()));
     }
 #endif // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size.pass.cpp
index 37bf73b5ca1..194daf9f956 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -141,4 +141,6 @@ int main()
         assert(c.key_eq() == test_compare<std::equal_to<int> >());
         assert((c.get_allocator() == min_allocator<std::pair<const int, std::string> >()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash.pass.cpp
index 9fbc5893fe9..4613e3ca554 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -143,4 +143,6 @@ int main()
         assert(c.key_eq() == test_compare<std::equal_to<int> >());
         assert((c.get_allocator() == min_allocator<std::pair<const int, std::string> >()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal.pass.cpp
index 398103dee09..582b68b94e2 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -146,4 +146,6 @@ int main()
         assert(c.key_eq() == test_compare<std::equal_to<int> >(9));
         assert((c.get_allocator() == min_allocator<std::pair<const int, std::string> >()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal_allocator.pass.cpp
index 2f81c2a01cb..9019d9221d0 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/init_size_hash_equal_allocator.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -207,4 +207,6 @@ int main()
         assert(c.key_eq() == test_compare<std::equal_to<int> >(9));
         assert(c.get_allocator() == A{});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move.pass.cpp
index 4bfc4d3b7ac..bfa2327e598 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -221,4 +221,6 @@ int main()
         assert(s2.size() == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_alloc.pass.cpp
index 2b711513bf9..d99c2ad9dea 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_alloc.pass.cpp
@@ -31,7 +31,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, std::string> P;
@@ -289,4 +289,6 @@ int main()
 
         assert(c0.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_assign_noexcept.pass.cpp
index 649dfd94b81..e6f7f4c999b 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_assign_noexcept.pass.cpp
@@ -43,7 +43,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly> C;
@@ -70,4 +70,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_noexcept.pass.cpp
index c1f6d3143fa..68ec2600aeb 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/move_noexcept.pass.cpp
@@ -40,7 +40,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -67,4 +67,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range.pass.cpp
index 3158236a461..4b916fa419a 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -262,4 +262,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size.pass.cpp
index 731207ef69f..aa45e074702 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -148,4 +148,6 @@ int main()
         assert((c.get_allocator() == min_allocator<std::pair<const int, std::string> >()));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash.pass.cpp
index a009d1372bc..ee9de7a4ec3 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash.pass.cpp
@@ -31,7 +31,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -151,4 +151,6 @@ int main()
         assert((c.get_allocator() == min_allocator<std::pair<const int, std::string> >()));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal.pass.cpp
index b6548bcc543..54c1f1e9d85 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal.pass.cpp
@@ -31,7 +31,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -153,4 +153,6 @@ int main()
         assert((c.get_allocator() == min_allocator<std::pair<const int, std::string> >()));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal_allocator.pass.cpp
index 288ad6dd365..68181d714c1 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/range_size_hash_equal_allocator.pass.cpp
@@ -32,7 +32,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string,
@@ -217,4 +217,6 @@ int main()
         assert(c.get_allocator() == A{});
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.fail.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.fail.cpp
index 284618117bc..122e3aec33f 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.fail.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -66,4 +66,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.pass.cpp
index 3c8c46bab80..9b58de89d9f 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -66,4 +66,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash.pass.cpp
index b299639ee0d..8dceccf5914 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -70,4 +70,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal.pass.cpp
index 2507e5e8fa4..5d32ec29bab 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -72,4 +72,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal_allocator.pass.cpp
index d9c6a60dfe8..254d89d99b5 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/size_hash_equal_allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<NotConstructible, NotConstructible,
@@ -96,4 +96,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/clear.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/clear.pass.cpp
index 2db684a52ee..71c3c57c215 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/clear.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -60,4 +60,6 @@ int main()
         assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace.pass.cpp
index aa38084df82..1a20fb876da 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace.pass.cpp
@@ -23,7 +23,7 @@
 #include "../../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, Emplaceable> C;
@@ -68,4 +68,6 @@ int main()
         assert(r->first == 5);
         assert(r->second == Emplaceable(6, 7));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp
index 3729b9e5f72..ef2904f3658 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp
@@ -25,7 +25,7 @@
 #include "min_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, Emplaceable> C;
@@ -88,4 +88,6 @@ int main()
         assert(r->first == 3);
         LIBCPP_ASSERT(r->second == Emplaceable(5, 6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_const_iter.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_const_iter.pass.cpp
index 0444252566c..5ab975077d8 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_const_iter.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_const_iter.pass.cpp
@@ -30,7 +30,7 @@ struct TemplateConstructor
 bool operator==(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 struct Hash { size_t operator() (const TemplateConstructor &) const { return 0; } };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -143,4 +143,6 @@ int main()
             m.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db1.pass.cpp
index 4986848cd2e..30fae95f759 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db1.pass.cpp
@@ -17,7 +17,7 @@
 #include <unordered_map>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -31,8 +31,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db2.pass.cpp
index 035a796e90d..3c0418497b0 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <cstdlib>
 #include <exception>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -34,8 +34,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db1.pass.cpp
index 8f38b65efc0..6c3a2cf3855 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db1.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db2.pass.cpp
index 7d6a7794aa9..6b0ea3528c7 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db3.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db3.pass.cpp
index 2502f123d95..0b53c1cdf08 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db3.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db3.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db4.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db4.pass.cpp
index a098f2a6698..7cea5e78938 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db4.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db4.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<int, int> P;
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_key.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_key.pass.cpp
index 7a94e3489bf..5e19c970a42 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_key.pass.cpp
@@ -37,7 +37,7 @@ bool only_deletions ( const Unordered &whole, const Unordered &part ) {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -385,4 +385,6 @@ int main()
     assert (only_deletions (m, m2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_range.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_range.pass.cpp
index 46ca4b40d5a..50f058422b9 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/erase_range.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -176,4 +176,6 @@ int main()
         assert(k == c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_iterator.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_iterator.pass.cpp
index b3ecc355619..a06aca77432 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_iterator.pass.cpp
@@ -40,7 +40,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using map_type = std::unordered_multimap<int, int>;
@@ -63,4 +63,6 @@ int main()
         min_alloc_map m = {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {5, 5}, {6, 6}};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_key.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_key.pass.cpp
index fb27c143447..272d5acfb76 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/extract_key.pass.cpp
@@ -45,7 +45,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_multimap<int, int> m =
@@ -73,4 +73,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_allocator_requirements.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_allocator_requirements.pass.cpp
index 855b5ea6111..73fe6b49b79 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_allocator_requirements.pass.cpp
@@ -19,8 +19,10 @@
 #include "container_test_types.h"
 #include "../../../map_allocator_requirement_test_templates.h"
 
-int main()
+int main(int, char**)
 {
   testMultimapInsert<TCT::unordered_multimap<> >();
   testMultimapInsertHint<TCT::unordered_multimap<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_const_lvalue.pass.cpp
index 112af3ca411..8eaa6950949 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_const_lvalue.pass.cpp
@@ -51,7 +51,7 @@ void do_insert_const_lvalue_test()
     assert(r->second == 4);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_const_lvalue_test<std::unordered_multimap<double, int> >();
 #if TEST_STD_VER >= 11
@@ -61,4 +61,6 @@ int main()
         do_insert_const_lvalue_test<C>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_const_lvalue.pass.cpp
index b21adc888c1..83cf7b86acb 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_const_lvalue.pass.cpp
@@ -56,7 +56,7 @@ void do_insert_const_lvalue_test()
     assert(r->second == 4);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_const_lvalue_test<std::unordered_multimap<double, int> >();
 #if TEST_STD_VER >= 11
@@ -79,4 +79,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_rvalue.pass.cpp
index 1485e2a8392..2993fe7572a 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_hint_rvalue.pass.cpp
@@ -28,7 +28,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<double, int> C;
@@ -173,4 +173,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_init.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_init.pass.cpp
index a707f77c59f..3a3f98785f2 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_init.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -117,4 +117,6 @@ int main()
         assert(static_cast<std::size_t>(std::distance(c.begin(), c.end())) == c.size());
         assert(static_cast<std::size_t>(std::distance(c.cbegin(), c.cend())) == c.size());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type.pass.cpp
index bbaf6aac0d8..fd1cfa114cc 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type.pass.cpp
@@ -67,10 +67,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_multimap<int, int> m;
     test(m);
     std::unordered_multimap<int, int, std::hash<int>, std::equal_to<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type_hint.pass.cpp
index ae36abb9229..70d207551a2 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_node_type_hint.pass.cpp
@@ -53,10 +53,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_multimap<int, int> m;
     test(m);
     std::unordered_multimap<int, int, std::hash<int>, std::equal_to<int>, min_allocator<std::pair<const int, int>>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_range.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_range.pass.cpp
index 4d0f37dbb86..333392af902 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_range.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<int, std::string> C;
@@ -118,4 +118,6 @@ int main()
         assert(static_cast<std::size_t>(std::distance(c.cbegin(), c.cend())) == c.size());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_rvalue.pass.cpp
index 58bb723797c..92b91b07c31 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_rvalue.pass.cpp
@@ -24,7 +24,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multimap<double, int> C;
@@ -152,4 +152,6 @@ int main()
         assert(r->first == 5.5);
         assert(r->second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/merge.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/merge.pass.cpp
index 0f590972f37..1ce1c8361ee 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/merge.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_hasher
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_multimap<int, int> src{{1, 0}, {3, 0}, {5, 0}};
@@ -153,4 +153,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/db_swap_1.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/db_swap_1.pass.cpp
index 8b0b8a4989e..3e15211d501 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/db_swap_1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/db_swap_1.pass.cpp
@@ -21,7 +21,7 @@
 #include <unordered_map>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if _LIBCPP_DEBUG >= 1
     {
@@ -40,4 +40,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp
index 6162cb2ff3b..971fff7930e 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp
@@ -118,7 +118,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
@@ -187,4 +187,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp
index 7b639ef5599..406978241d1 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -579,4 +579,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/allocator_mismatch.fail.cpp
index 1ff880b4e8a..6183761a32c 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <unordered_set>
 
-int main()
+int main(int, char**)
 {
     std::unordered_multiset<int, std::hash<int>, std::less<int>, std::allocator<long> > v;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/bucket.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/bucket.pass.cpp
index a0837f9fd86..4aeb8493320 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/bucket.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/bucket.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -73,4 +73,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/bucket_count.pass.cpp
index b6f7349612f..8f389ebc206 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/bucket_count.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -70,4 +70,6 @@ int main()
         assert(c.bucket_count() >= 8);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/bucket_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/bucket_size.pass.cpp
index 78e8c68268a..99b76972aa0 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/bucket_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/bucket_size.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -81,4 +81,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/clear.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/clear.pass.cpp
index 449de3520cc..01ff0459383 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/clear.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/clear.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -59,4 +59,6 @@ int main()
         assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/count.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/count.pass.cpp
index 2eb50539b20..40cef2af203 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/count.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -66,4 +66,6 @@ int main()
         assert(c.count(5) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/db_iterators_7.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/db_iterators_7.pass.cpp
index 7f82cf65cb3..8da63023389 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/db_iterators_7.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/db_iterators_7.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -50,8 +50,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/db_iterators_8.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/db_iterators_8.pass.cpp
index 305a76f240b..8bc1e5c168d 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/db_iterators_8.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/db_iterators_8.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_7.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_7.pass.cpp
index e12e3cefb95..fbf40ca6eab 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_7.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_7.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -49,8 +49,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_8.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_8.pass.cpp
index 51ccf32ae0a..53c9c9bd58b 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_8.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/db_local_iterators_8.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/emplace.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/emplace.pass.cpp
index efbaa35aaa4..67c5d164206 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/emplace.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/emplace.pass.cpp
@@ -23,7 +23,7 @@
 #include "../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<Emplaceable> C;
@@ -58,4 +58,6 @@ int main()
         assert(c.size() == 3);
         assert(*r == Emplaceable(5, 6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/emplace_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/emplace_hint.pass.cpp
index 715b77425bd..61f06edd485 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/emplace_hint.pass.cpp
@@ -24,7 +24,7 @@
 #include "../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<Emplaceable> C;
@@ -61,4 +61,6 @@ int main()
         assert(c.size() == 3);
         assert(*r == Emplaceable(5, 6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/empty.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/empty.fail.cpp
index 1aeffd599f1..449b2116a54 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/empty.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::unordered_multiset<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/empty.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/empty.pass.cpp
index f96e944a3dd..078f95f564b 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/empty.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multiset<int> M;
@@ -42,4 +42,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/eq.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/eq.pass.cpp
index 6681e05eea2..761ad7051e7 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/eq.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/eq.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -176,4 +176,6 @@ int main()
         assert(!(c1 != c2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/equal_range_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/equal_range_const.pass.cpp
index 77bfb557b49..ddfd77e18c6 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/equal_range_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/equal_range_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -86,4 +86,6 @@ int main()
         assert(*r.first == 50);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/equal_range_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/equal_range_non_const.pass.cpp
index c3da35a48e7..a148f65b173 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/equal_range_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/equal_range_non_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -86,4 +86,6 @@ int main()
         assert(*r.first == 50);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_const_iter.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_const_iter.pass.cpp
index daa39956a6d..0a92f7d0621 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_const_iter.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_const_iter.pass.cpp
@@ -28,7 +28,7 @@ struct TemplateConstructor
 bool operator==(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 struct Hash { size_t operator() (const TemplateConstructor &) const { return 0; } };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -96,4 +96,6 @@ int main()
             m.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_if.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_if.pass.cpp
index 761b94e1d7d..bd587473ce7 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_if.pass.cpp
@@ -79,7 +79,7 @@ void test()
     test0<S>({1,2,3}, False, {1,2,3});
 }
 
-int main()
+int main(int, char**)
 {
     test<std::unordered_multiset<int>>();
     test<std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>>> ();
@@ -87,4 +87,6 @@ int main()
 
     test<std::unordered_multiset<long>>();
     test<std::unordered_multiset<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db1.pass.cpp
index 742fe2bc2d4..073043f5a36 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db1.pass.cpp
@@ -17,7 +17,7 @@
 #include <unordered_set>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -30,8 +30,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db2.pass.cpp
index 9a6e09d4735..28768eaf5c2 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <cstdlib>
 #include <exception>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db1.pass.cpp
index dac9ac6afad..0a9853d66e3 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db1.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db2.pass.cpp
index f2eb5277ee7..cc1ec00961a 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db3.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db3.pass.cpp
index a3e2d8cce10..a1de8cb7c71 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db3.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db3.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db4.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db4.pass.cpp
index 41cc1f8737e..a82ecfc3cc3 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db4.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_iter_iter_db4.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -31,8 +31,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_key.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_key.pass.cpp
index 1ed8cd70490..ba7248d7468 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_key.pass.cpp
@@ -36,7 +36,7 @@ bool only_deletions ( const Unordered &whole, const Unordered &part ) {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -172,4 +172,6 @@ int main()
     assert (only_deletions (m, m2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/erase_range.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/erase_range.pass.cpp
index 8c1f8479a62..c6bb4b597c3 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/erase_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/erase_range.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -91,4 +91,6 @@ int main()
         assert(k == c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/extract_iterator.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/extract_iterator.pass.cpp
index e0a0f96b9ff..01994120c8a 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/extract_iterator.pass.cpp
@@ -36,7 +36,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using set_type = std::unordered_multiset<int>;
@@ -56,4 +56,6 @@ int main()
         min_alloc_set m = {1, 2, 3, 4, 5, 6};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/extract_key.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/extract_key.pass.cpp
index 78d763ff5df..380b39f85e2 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/extract_key.pass.cpp
@@ -43,7 +43,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_multiset<int> m = {1, 2, 3, 4, 5, 6};
@@ -67,4 +67,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/find_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/find_const.pass.cpp
index 8d6da19452a..efa8bfc12b5 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/find_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/find_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -64,4 +64,6 @@ int main()
         assert(i == c.cend());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/find_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/find_non_const.pass.cpp
index 713f1ebe10a..4eeb8ac6a80 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/find_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/find_non_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -64,4 +64,6 @@ int main()
         assert(i == c.cend());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/incomplete.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/incomplete.pass.cpp
index 67fe1a9c084..0aeb246ca43 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/incomplete.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/incomplete.pass.cpp
@@ -32,6 +32,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_const_lvalue.pass.cpp
index 90666e0c14f..8200dc2fc94 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_const_lvalue.pass.cpp
@@ -46,7 +46,7 @@ void do_insert_const_lvalue_test()
     assert(*r == 5.5);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_const_lvalue_test<std::unordered_multiset<double> >();
 #if TEST_STD_VER >= 11
@@ -56,4 +56,6 @@ int main()
         do_insert_const_lvalue_test<C>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_emplace_allocator_requirements.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_emplace_allocator_requirements.pass.cpp
index bc14294c38c..d7474f24e7c 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_emplace_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_emplace_allocator_requirements.pass.cpp
@@ -18,8 +18,10 @@
 #include "container_test_types.h"
 #include "../../set_allocator_requirement_test_templates.h"
 
-int main()
+int main(int, char**)
 {
   testMultisetInsert<TCT::unordered_multiset<> >();
   testMultisetEmplace<TCT::unordered_multiset<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_hint_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_hint_const_lvalue.pass.cpp
index 283368091e8..ede013ef99e 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_hint_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_hint_const_lvalue.pass.cpp
@@ -51,7 +51,7 @@ void do_insert_hint_const_lvalue_test()
     assert(*r == 5.5);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_hint_const_lvalue_test<std::unordered_multiset<double> >();
 #if TEST_STD_VER >= 11
@@ -74,4 +74,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_hint_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_hint_rvalue.pass.cpp
index 39c04a1b66c..ab5302462e9 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_hint_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_hint_rvalue.pass.cpp
@@ -21,7 +21,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<double> C;
@@ -115,4 +115,6 @@ int main()
         assert(*r == 5);
     }
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_init.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_init.pass.cpp
index 60d58c0d240..4467c74b439 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_init.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -65,4 +65,6 @@ int main()
         assert(c.count(3) == 1);
         assert(c.count(4) == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_node_type.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_node_type.pass.cpp
index 0a06fe6b922..c660ab22d6b 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_node_type.pass.cpp
@@ -66,10 +66,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_multiset<int> m;
     test(m);
     std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_node_type_hint.pass.cpp
index 36434680579..e95dd31e39e 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_node_type_hint.pass.cpp
@@ -49,10 +49,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_multiset<int> m;
     test(m);
     std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_range.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_range.pass.cpp
index 2487a2d4bd1..b8742f520b9 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_range.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -66,4 +66,6 @@ int main()
         assert(c.count(4) == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/insert_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/insert_rvalue.pass.cpp
index 056288c78c1..1bec2b7e6c2 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/insert_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/insert_rvalue.pass.cpp
@@ -21,7 +21,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<double> C;
@@ -111,4 +111,6 @@ int main()
         assert(*r == 5);
     }
 #endif  // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/iterators.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/iterators.fail.cpp
index 3cf31d52c01..2c282fdbaab 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/iterators.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/iterators.fail.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -65,4 +65,6 @@ int main()
         assert(std::distance(c.begin(), c.end()) == c.size());
         assert(std::distance(c.cbegin(), c.cend()) == c.size());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/iterators.pass.cpp
index b6147e9c64d..2c0cd496ddb 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/iterators.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -125,4 +125,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/load_factor.pass.cpp
index ece450ceb17..bb3350e8689 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/load_factor.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -71,4 +71,6 @@ int main()
         assert(c.load_factor() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/local_iterators.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/local_iterators.fail.cpp
index a27353414a6..d6f1a55fd49 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/local_iterators.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/local_iterators.fail.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -259,4 +259,6 @@ int main()
         j = c.cend(b);
         assert(std::distance(i, j) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/local_iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/local_iterators.pass.cpp
index b63a94ae100..5aa65756371 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/local_iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/local_iterators.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -496,4 +496,6 @@ int main()
         assert(std::distance(i, j) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/max_bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/max_bucket_count.pass.cpp
index c503a35378e..7fb76c41c49 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/max_bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/max_bucket_count.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -34,4 +34,6 @@ int main()
         assert(c.max_bucket_count() > 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/max_load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/max_load_factor.pass.cpp
index 1a6b1335a62..c89aa6d339f 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/max_load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/max_load_factor.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -62,4 +62,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/max_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/max_size.pass.cpp
index a6a7dae2519..d08cdb6221f 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/max_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
       typedef limited_allocator<int, 10> A;
@@ -50,4 +50,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/merge.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/merge.pass.cpp
index 1082f4990f8..e951b33d212 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/merge.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_hasher
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_multiset<int> src{1, 3, 5};
@@ -150,4 +150,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/rehash.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/rehash.pass.cpp
index 38691f20040..8c6699b18e2 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/rehash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/rehash.pass.cpp
@@ -36,7 +36,7 @@ void test(const C& c)
     assert(c.count(4) == 1);
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -99,4 +99,6 @@ int main()
         test(c);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/reserve.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/reserve.pass.cpp
index 079786689f6..54eada5a769 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/reserve.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/reserve.pass.cpp
@@ -45,7 +45,7 @@ void reserve_invariant(size_t n) // LWG #2156
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int> C;
@@ -103,4 +103,6 @@ int main()
     }
 #endif
     reserve_invariant(20);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/scary.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/scary.pass.cpp
index 7ef4a513f64..670c6406a2b 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/scary.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/scary.pass.cpp
@@ -14,11 +14,13 @@
 
 #include <unordered_set>
 
-int main()
+int main(int, char**)
 {
     typedef std::unordered_set<int> M1;
     typedef std::unordered_multiset<int> M2;
     M2::iterator i;
     M1::iterator j = i;
     ((void)j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/size.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/size.pass.cpp
index 3aae7dd53c2..12a4733ccb1 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_multiset<int> M;
@@ -58,4 +58,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/swap_member.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/swap_member.pass.cpp
index 2937e444e4a..bad8df9d9f0 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/swap_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/swap_member.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -566,4 +566,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/types.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/types.pass.cpp
index 8b246778d49..81f8334c28f 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/types.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/types.pass.cpp
@@ -31,7 +31,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<short> C;
@@ -65,4 +65,6 @@ int main()
         static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/allocator.pass.cpp
index e446fa65e32..2a3b867b5e0 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -106,4 +106,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_copy.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_copy.pass.cpp
index c90a0106af8..1fcd71002e9 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_copy.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -209,4 +209,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_init.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_init.pass.cpp
index cf286319d42..795370c44fe 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_init.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -93,4 +93,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_move.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_move.pass.cpp
index 00adca3c452..1ed77851cf3 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/assign_move.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -263,4 +263,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/compare_copy_constructible.fail.cpp
index b1e161b42e0..4b8d55cac98 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/compare_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_multiset<int, std::hash<int>, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy.pass.cpp
index e3a57fa5554..f3ca15241ad 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -168,4 +168,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy_alloc.pass.cpp
index aac5fde6a79..4e99490ea61 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/copy_alloc.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -122,4 +122,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default.pass.cpp
index 85fc84896b8..bb762b576ca 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -104,4 +104,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default_noexcept.pass.cpp
index 71661d5ea15..4acda32557d 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/default_noexcept.pass.cpp
@@ -44,7 +44,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -71,4 +71,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/dtor_noexcept.pass.cpp
index c65c0f15e10..1d963b6be7b 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/dtor_noexcept.pass.cpp
@@ -37,7 +37,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<MoveOnly> C;
@@ -64,4 +64,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/hash_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/hash_copy_constructible.fail.cpp
index 97b031ab81a..9e24ce2ecbc 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/hash_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/hash_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_multiset<int, Hash<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init.pass.cpp
index 7b3d996f788..d8fc0c0021c 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -160,4 +160,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size.pass.cpp
index 475f2664da0..bda874ce559 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -94,4 +94,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash.pass.cpp
index de5f6ae174d..5c81a3461e1 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -97,4 +97,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal.pass.cpp
index cffd9d55eb1..c77d85057ae 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -99,4 +99,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal_allocator.pass.cpp
index 57df3014520..8a26b3948ec 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/init_size_hash_equal_allocator.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -101,4 +101,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move.pass.cpp
index 670102be419..196044f21c6 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -171,4 +171,6 @@ int main()
         assert(s2.size() == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_alloc.pass.cpp
index 5e822b4587f..eb567a9da75 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_alloc.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int P;
@@ -202,4 +202,6 @@ int main()
 
         assert(c0.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_assign_noexcept.pass.cpp
index 702125b661e..4b0051a9be5 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_assign_noexcept.pass.cpp
@@ -43,7 +43,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<MoveOnly> C;
@@ -70,4 +70,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_noexcept.pass.cpp
index 03f61a504d3..3941940f9a0 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/move_noexcept.pass.cpp
@@ -40,7 +40,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -67,4 +67,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range.pass.cpp
index 5d729ec4965..953e702a682 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -166,4 +166,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size.pass.cpp
index d423c886488..2b7e911cd8f 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -100,4 +100,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash.pass.cpp
index 84f7d5a1310..1b394413041 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -103,4 +103,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal.pass.cpp
index 93d92257cb0..d83555f57e6 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -105,4 +105,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal_allocator.pass.cpp
index e8e425f2df7..10c69c27ab8 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/range_size_hash_equal_allocator.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<int,
@@ -108,4 +108,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.fail.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.fail.cpp
index d115f98fe1e..45d67f33a61 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.fail.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -62,4 +62,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.pass.cpp
index 2e1c749f2ce..ba32ec37055 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -62,4 +62,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash.pass.cpp
index 3868b372003..47d0867f0f9 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -66,4 +66,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal.pass.cpp
index eebcc14a68b..f9cc2503b68 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -68,4 +68,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal_allocator.pass.cpp
index ab2ac6ee547..8e25bf00e21 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.cnstr/size_hash_equal_allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<NotConstructible,
@@ -70,4 +70,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/db_swap_1.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/db_swap_1.pass.cpp
index 3ad54c42fba..a546d0d7d1d 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/db_swap_1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/db_swap_1.pass.cpp
@@ -21,7 +21,7 @@
 #include <unordered_set>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if _LIBCPP_DEBUG >= 1
     {
@@ -39,4 +39,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp
index 73c3cc66a0d..3586e8d5bd5 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp
@@ -118,7 +118,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_multiset<MoveOnly> C;
@@ -186,4 +186,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_non_member.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_non_member.pass.cpp
index 60826ffd199..706c995f3de 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_non_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_non_member.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -566,4 +566,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/allocator_mismatch.fail.cpp b/libcxx/test/std/containers/unord/unord.set/allocator_mismatch.fail.cpp
index 6286031e590..0d1341e6939 100644
--- a/libcxx/test/std/containers/unord/unord.set/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <unordered_set>
 
-int main()
+int main(int, char**)
 {
     std::unordered_set<int, std::hash<int>, std::less<int>, std::allocator<long> > v;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/bucket.pass.cpp b/libcxx/test/std/containers/unord/unord.set/bucket.pass.cpp
index 58d77e3d57a..2215b99493b 100644
--- a/libcxx/test/std/containers/unord/unord.set/bucket.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/bucket.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -72,4 +72,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.set/bucket_count.pass.cpp
index 3dadbd21a97..3a1a78cb3d8 100644
--- a/libcxx/test/std/containers/unord/unord.set/bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/bucket_count.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -68,4 +68,6 @@ int main()
         assert(c.bucket_count() >= 8);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/bucket_size.pass.cpp b/libcxx/test/std/containers/unord/unord.set/bucket_size.pass.cpp
index e37e047af66..6ca89d57224 100644
--- a/libcxx/test/std/containers/unord/unord.set/bucket_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/bucket_size.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -76,4 +76,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/clear.pass.cpp b/libcxx/test/std/containers/unord/unord.set/clear.pass.cpp
index abaaec3e258..ab04cdd9105 100644
--- a/libcxx/test/std/containers/unord/unord.set/clear.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/clear.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -58,4 +58,6 @@ int main()
         assert(c.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/count.pass.cpp b/libcxx/test/std/containers/unord/unord.set/count.pass.cpp
index 97694684de0..971e126fdc6 100644
--- a/libcxx/test/std/containers/unord/unord.set/count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/count.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -65,4 +65,6 @@ int main()
         assert(c.count(5) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/db_iterators_7.pass.cpp b/libcxx/test/std/containers/unord/unord.set/db_iterators_7.pass.cpp
index ef58e256133..8420de60d33 100644
--- a/libcxx/test/std/containers/unord/unord.set/db_iterators_7.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/db_iterators_7.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -50,8 +50,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/db_iterators_8.pass.cpp b/libcxx/test/std/containers/unord/unord.set/db_iterators_8.pass.cpp
index 10692fa4904..14dccf97db0 100644
--- a/libcxx/test/std/containers/unord/unord.set/db_iterators_8.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/db_iterators_8.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/db_local_iterators_7.pass.cpp b/libcxx/test/std/containers/unord/unord.set/db_local_iterators_7.pass.cpp
index e3a04f6a95f..ac066af7fbe 100644
--- a/libcxx/test/std/containers/unord/unord.set/db_local_iterators_7.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/db_local_iterators_7.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -49,8 +49,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/db_local_iterators_8.pass.cpp b/libcxx/test/std/containers/unord/unord.set/db_local_iterators_8.pass.cpp
index 57dfda6fc68..a1595cd3601 100644
--- a/libcxx/test/std/containers/unord/unord.set/db_local_iterators_8.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/db_local_iterators_8.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef int T;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/emplace.pass.cpp b/libcxx/test/std/containers/unord/unord.set/emplace.pass.cpp
index 32e6e348722..6616aa51c2c 100644
--- a/libcxx/test/std/containers/unord/unord.set/emplace.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/emplace.pass.cpp
@@ -23,7 +23,7 @@
 #include "../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<Emplaceable> C;
@@ -64,4 +64,6 @@ int main()
         assert(*r.first == Emplaceable(5, 6));
         assert(!r.second);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/emplace_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.set/emplace_hint.pass.cpp
index 1bab8d9c329..55b3ccbc978 100644
--- a/libcxx/test/std/containers/unord/unord.set/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/emplace_hint.pass.cpp
@@ -24,7 +24,7 @@
 #include "../../Emplaceable.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<Emplaceable> C;
@@ -61,4 +61,6 @@ int main()
         assert(c.size() == 2);
         assert(*r == Emplaceable(5, 6));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/empty.fail.cpp b/libcxx/test/std/containers/unord/unord.set/empty.fail.cpp
index f683f23a7f3..11273f44fce 100644
--- a/libcxx/test/std/containers/unord/unord.set/empty.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::unordered_set<int> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/empty.pass.cpp b/libcxx/test/std/containers/unord/unord.set/empty.pass.cpp
index 3656e60c0ed..ce9cfdcf5f4 100644
--- a/libcxx/test/std/containers/unord/unord.set/empty.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/empty.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_set<int> M;
@@ -42,4 +42,6 @@ int main()
     assert(m.empty());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/eq.pass.cpp b/libcxx/test/std/containers/unord/unord.set/eq.pass.cpp
index 82737f1ba05..5362f57f4f5 100644
--- a/libcxx/test/std/containers/unord/unord.set/eq.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/eq.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -155,4 +155,6 @@ int main()
         assert(!(c1 != c2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/equal_range_const.pass.cpp b/libcxx/test/std/containers/unord/unord.set/equal_range_const.pass.cpp
index 587971b743a..9489deaf2ea 100644
--- a/libcxx/test/std/containers/unord/unord.set/equal_range_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/equal_range_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -77,4 +77,6 @@ int main()
         assert(*r.first == 50);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/equal_range_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.set/equal_range_non_const.pass.cpp
index 923c1764d94..6713dbd91e0 100644
--- a/libcxx/test/std/containers/unord/unord.set/equal_range_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/equal_range_non_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -77,4 +77,6 @@ int main()
         assert(*r.first == 50);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_const_iter.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_const_iter.pass.cpp
index 84f4f81d19a..3d9cfe6834f 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_const_iter.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_const_iter.pass.cpp
@@ -28,7 +28,7 @@ struct TemplateConstructor
 bool operator==(const TemplateConstructor&, const TemplateConstructor&) { return false; }
 struct Hash { size_t operator() (const TemplateConstructor &) const { return 0; } };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -94,4 +94,6 @@ int main()
             m.erase(it);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_if.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_if.pass.cpp
index 2b5f8f6c87b..cbd2ebb1afb 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_if.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_if.pass.cpp
@@ -69,7 +69,7 @@ void test()
     test0<S>({1,2,3}, False, {1,2,3});
 }
 
-int main()
+int main(int, char**)
 {
     test<std::unordered_set<int>>();
     test<std::unordered_set<int, std::hash<int>, std::equal_to<int>, min_allocator<int>>> ();
@@ -77,4 +77,6 @@ int main()
 
     test<std::unordered_set<long>>();
     test<std::unordered_set<double>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_iter_db1.pass.cpp
index 3bf6282ccc2..a65086ee8c6 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_iter_db1.pass.cpp
@@ -17,7 +17,7 @@
 #include <unordered_set>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -30,8 +30,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_iter_db2.pass.cpp
index 34f8a60766e..c7f64da355c 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <cstdlib>
 #include <exception>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -33,8 +33,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db1.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db1.pass.cpp
index bcf3df82b77..002a24bf1bc 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db1.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db2.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db2.pass.cpp
index 1a222d91ba3..59bf0cc33fe 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db2.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db2.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db3.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db3.pass.cpp
index 83cc5d558d5..c522fce2633 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db3.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db3.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -32,8 +32,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db4.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db4.pass.cpp
index 218d50137b6..a7c3c002075 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db4.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_iter_iter_db4.pass.cpp
@@ -19,7 +19,7 @@
 #include <exception>
 #include <cstdlib>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {1, 2, 3};
@@ -31,8 +31,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_key.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_key.pass.cpp
index ea80e2d019c..912a4ae6b15 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_key.pass.cpp
@@ -36,7 +36,7 @@ bool only_deletions ( const Unordered &whole, const Unordered &part ) {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -171,4 +171,6 @@ int main()
     assert (only_deletions (m, m2));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/erase_range.pass.cpp b/libcxx/test/std/containers/unord/unord.set/erase_range.pass.cpp
index 11908637bf6..907063c6a5a 100644
--- a/libcxx/test/std/containers/unord/unord.set/erase_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/erase_range.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -90,4 +90,6 @@ int main()
         assert(k == c.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/extract_iterator.pass.cpp b/libcxx/test/std/containers/unord/unord.set/extract_iterator.pass.cpp
index e03e11ff672..03dfcc60284 100644
--- a/libcxx/test/std/containers/unord/unord.set/extract_iterator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/extract_iterator.pass.cpp
@@ -36,7 +36,7 @@ void test(Container& c)
     assert(c.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         using set_type = std::unordered_set<int>;
@@ -56,4 +56,6 @@ int main()
         min_alloc_set m = {1, 2, 3, 4, 5, 6};
         test(m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/extract_key.pass.cpp b/libcxx/test/std/containers/unord/unord.set/extract_key.pass.cpp
index 9a612371480..b2a6f04935b 100644
--- a/libcxx/test/std/containers/unord/unord.set/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/extract_key.pass.cpp
@@ -43,7 +43,7 @@ void test(Container& c, KeyTypeIter first, KeyTypeIter last)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_set<int> m = {1, 2, 3, 4, 5, 6};
@@ -67,4 +67,6 @@ int main()
         int keys[] = {1, 2, 3, 4, 5, 6};
         test(m, std::begin(keys), std::end(keys));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/find_const.pass.cpp b/libcxx/test/std/containers/unord/unord.set/find_const.pass.cpp
index e46e3d5f1d7..f226a69606f 100644
--- a/libcxx/test/std/containers/unord/unord.set/find_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/find_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -63,4 +63,6 @@ int main()
         assert(i == c.cend());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/find_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.set/find_non_const.pass.cpp
index bbd37754eed..4b24b2f447c 100644
--- a/libcxx/test/std/containers/unord/unord.set/find_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/find_non_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -63,4 +63,6 @@ int main()
         assert(i == c.cend());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/incomplete.pass.cpp b/libcxx/test/std/containers/unord/unord.set/incomplete.pass.cpp
index 12c95353cf6..b77f679fef5 100644
--- a/libcxx/test/std/containers/unord/unord.set/incomplete.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/incomplete.pass.cpp
@@ -32,6 +32,8 @@ struct A {
 
 inline bool operator==(A const& L, A const& R) { return &L == &R; }
 
-int main() {
+int main(int, char**) {
     A a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_and_emplace_allocator_requirements.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_and_emplace_allocator_requirements.pass.cpp
index fffd108a783..34905e3c8dc 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_and_emplace_allocator_requirements.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_and_emplace_allocator_requirements.pass.cpp
@@ -21,8 +21,10 @@
 #include "../../set_allocator_requirement_test_templates.h"
 
 
-int main()
+int main(int, char**)
 {
   testSetInsert<TCT::unordered_set<> >();
   testSetEmplace<TCT::unordered_set<> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_const_lvalue.pass.cpp
index 820ac6e907c..097b221a65b 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_const_lvalue.pass.cpp
@@ -50,7 +50,7 @@ void do_insert_const_lvalue_test()
     assert(r.second);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_const_lvalue_test<std::unordered_set<double> >();
 #if TEST_STD_VER >= 11
@@ -60,4 +60,6 @@ int main()
         do_insert_const_lvalue_test<C>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_hint_const_lvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_hint_const_lvalue.pass.cpp
index 3ca654764a1..e3765ca02cb 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_hint_const_lvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_hint_const_lvalue.pass.cpp
@@ -51,7 +51,7 @@ void do_insert_hint_const_lvalue_test()
     assert(*r == 5.5);
 }
 
-int main()
+int main(int, char**)
 {
     do_insert_hint_const_lvalue_test<std::unordered_set<double> >();
 #if TEST_STD_VER >= 11
@@ -74,4 +74,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_hint_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_hint_rvalue.pass.cpp
index f4a38dcfbef..071708e1eac 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_hint_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_hint_rvalue.pass.cpp
@@ -21,7 +21,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<double> C;
@@ -115,4 +115,6 @@ int main()
         assert(*r == 5);
     }
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_init.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_init.pass.cpp
index 2af3d373287..c60fcb16bff 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_init.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -65,4 +65,6 @@ int main()
         assert(c.count(3) == 1);
         assert(c.count(4) == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_node_type.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_node_type.pass.cpp
index 8eed6586556..f41c936857b 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_node_type.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_node_type.pass.cpp
@@ -73,10 +73,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_set<int> m;
     test(m);
     std::unordered_set<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_node_type_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_node_type_hint.pass.cpp
index bf8c1277649..ae5e8976e48 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_node_type_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_node_type_hint.pass.cpp
@@ -51,10 +51,12 @@ void test(Container& c)
     }
 }
 
-int main()
+int main(int, char**)
 {
     std::unordered_set<int> m;
     test(m);
     std::unordered_set<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> m2;
     test(m2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_range.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_range.pass.cpp
index d0c4d7e85d1..cb365483a9d 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_range.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_iterators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -66,4 +66,6 @@ int main()
         assert(c.count(4) == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/insert_rvalue.pass.cpp b/libcxx/test/std/containers/unord/unord.set/insert_rvalue.pass.cpp
index 75342b7c3bc..9edab274041 100644
--- a/libcxx/test/std/containers/unord/unord.set/insert_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/insert_rvalue.pass.cpp
@@ -21,7 +21,7 @@
 #include "MoveOnly.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<double> C;
@@ -127,4 +127,6 @@ int main()
         assert(r.second);
     }
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/iterators.fail.cpp b/libcxx/test/std/containers/unord/unord.set/iterators.fail.cpp
index 8ded4e0233a..de5f88e792f 100644
--- a/libcxx/test/std/containers/unord/unord.set/iterators.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/iterators.fail.cpp
@@ -22,7 +22,7 @@
 #include <unordered_set>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -63,4 +63,6 @@ int main()
         assert(std::distance(c.begin(), c.end()) == c.size());
         assert(std::distance(c.cbegin(), c.cend()) == c.size());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.set/iterators.pass.cpp
index 73b1a4c5402..eb8459101b2 100644
--- a/libcxx/test/std/containers/unord/unord.set/iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/iterators.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -125,4 +125,6 @@ int main()
         assert (!(cii != ii1 ));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.set/load_factor.pass.cpp
index 06d17dc905c..c5857b7b47c 100644
--- a/libcxx/test/std/containers/unord/unord.set/load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/load_factor.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -71,4 +71,6 @@ int main()
         assert(c.load_factor() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/local_iterators.fail.cpp b/libcxx/test/std/containers/unord/unord.set/local_iterators.fail.cpp
index b7c3d9b6b54..7bacd2f6f76 100644
--- a/libcxx/test/std/containers/unord/unord.set/local_iterators.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/local_iterators.fail.cpp
@@ -22,7 +22,7 @@
 #include <unordered_set>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -257,4 +257,6 @@ int main()
         j = c.cend(b);
         assert(std::distance(i, j) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/local_iterators.pass.cpp b/libcxx/test/std/containers/unord/unord.set/local_iterators.pass.cpp
index 0797c1ec8b9..ad3de5b0ae0 100644
--- a/libcxx/test/std/containers/unord/unord.set/local_iterators.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/local_iterators.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -384,4 +384,6 @@ int main()
         assert(*i == 4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/max_bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.set/max_bucket_count.pass.cpp
index 88471bbaf8e..121147a08e7 100644
--- a/libcxx/test/std/containers/unord/unord.set/max_bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/max_bucket_count.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -34,4 +34,6 @@ int main()
         assert(c.max_bucket_count() > 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/max_load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.set/max_load_factor.pass.cpp
index 35028a827d1..ac345a1d4ea 100644
--- a/libcxx/test/std/containers/unord/unord.set/max_load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/max_load_factor.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -62,4 +62,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/max_size.pass.cpp b/libcxx/test/std/containers/unord/unord.set/max_size.pass.cpp
index 5ec2af75b74..aeb1354da56 100644
--- a/libcxx/test/std/containers/unord/unord.set/max_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/max_size.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_allocator.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
       typedef limited_allocator<int, 10> A;
@@ -46,4 +46,6 @@ int main()
       assert(c.max_size() <= max_dist);
       assert(c.max_size() <= alloc_max_size(c.get_allocator()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/merge.pass.cpp b/libcxx/test/std/containers/unord/unord.set/merge.pass.cpp
index 91dd476d4f9..4a11867ed2a 100644
--- a/libcxx/test/std/containers/unord/unord.set/merge.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/merge.pass.cpp
@@ -49,7 +49,7 @@ struct throw_hasher
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::unordered_set<int> src{1, 3, 5};
@@ -150,4 +150,5 @@ int main()
             first.merge(std::move(second));
         }
     }
+    return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/rehash.pass.cpp b/libcxx/test/std/containers/unord/unord.set/rehash.pass.cpp
index c373b1632d5..e45327ad7ec 100644
--- a/libcxx/test/std/containers/unord/unord.set/rehash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/rehash.pass.cpp
@@ -36,7 +36,7 @@ void test(const C& c)
     assert(c.count(4) == 1);
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -99,4 +99,6 @@ int main()
         test(c);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/reserve.pass.cpp b/libcxx/test/std/containers/unord/unord.set/reserve.pass.cpp
index a852f10223d..7ea358e889d 100644
--- a/libcxx/test/std/containers/unord/unord.set/reserve.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/reserve.pass.cpp
@@ -45,7 +45,7 @@ void reserve_invariant(size_t n) // LWG #2156
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int> C;
@@ -103,4 +103,6 @@ int main()
     }
 #endif
     reserve_invariant(20);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/size.pass.cpp b/libcxx/test/std/containers/unord/unord.set/size.pass.cpp
index e3e488461c9..f7967fcd5f7 100644
--- a/libcxx/test/std/containers/unord/unord.set/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/size.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unordered_set<int> M;
@@ -58,4 +58,6 @@ int main()
     assert(m.size() == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/swap_member.pass.cpp b/libcxx/test/std/containers/unord/unord.set/swap_member.pass.cpp
index 9c34e8de9c5..0877b14f763 100644
--- a/libcxx/test/std/containers/unord/unord.set/swap_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/swap_member.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -566,4 +566,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/types.pass.cpp b/libcxx/test/std/containers/unord/unord.set/types.pass.cpp
index 7beafedc2c5..7b1531dc28f 100644
--- a/libcxx/test/std/containers/unord/unord.set/types.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/types.pass.cpp
@@ -31,7 +31,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<short> C;
@@ -65,4 +65,6 @@ int main()
         static_assert((std::is_same<C::difference_type, std::ptrdiff_t>::value), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/allocator.pass.cpp
index d6e604d7202..920244aae82 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -106,4 +106,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_copy.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_copy.pass.cpp
index 083ebda3f2a..10952954284 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_copy.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -184,4 +184,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_init.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_init.pass.cpp
index 515022124a4..bbb2045cb9c 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_init.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -93,4 +93,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_move.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_move.pass.cpp
index 9c8d055a945..15741254d96 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/assign_move.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_allocator<int> A;
@@ -210,4 +210,6 @@ int main()
         assert(fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/compare_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/compare_copy_constructible.fail.cpp
index 21cd61458c6..0638027fd81 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/compare_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/compare_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_set<int, std::hash<int>, Comp<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy.pass.cpp
index 652f2e4a442..179e6e473c8 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -144,4 +144,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy_alloc.pass.cpp
index 800f4f36ad0..970da087717 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/copy_alloc.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -106,4 +106,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default.pass.cpp
index 52cda0692d9..1fa2932e5a5 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -104,4 +104,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default_noexcept.pass.cpp
index 533c10df4c0..5d6508d464b 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/default_noexcept.pass.cpp
@@ -44,7 +44,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -71,4 +71,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/dtor_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/dtor_noexcept.pass.cpp
index 7041c8263a4..2225469e9e5 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/dtor_noexcept.pass.cpp
@@ -37,7 +37,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<MoveOnly> C;
@@ -64,4 +64,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/hash_copy_constructible.fail.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/hash_copy_constructible.fail.cpp
index 0ddae66710c..92550a0962f 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/hash_copy_constructible.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/hash_copy_constructible.fail.cpp
@@ -23,6 +23,8 @@ private:
     };
 
 
-int main() {
+int main(int, char**) {
     std::unordered_set<int, Hash<int> > m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init.pass.cpp
index 1550727d8fe..8bf0453c320 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
   {
         typedef std::unordered_set<int,
@@ -160,4 +160,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size.pass.cpp
index 54b6fbd7185..3e58ce92836 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -94,4 +94,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash.pass.cpp
index d7330c3bd76..3761cc33dde 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -97,4 +97,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal.pass.cpp
index 1741320bc95..7123e341509 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -99,4 +99,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal_allocator.pass.cpp
index ac13691693e..94aa74f2434 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/init_size_hash_equal_allocator.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -101,4 +101,6 @@ int main()
         assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move.pass.cpp
index 0bbf312bd68..5b599ae71d4 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -171,4 +171,6 @@ int main()
         assert(s2.size() == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_alloc.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_alloc.pass.cpp
index 03567db22a1..bc6629acdb7 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_alloc.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int P;
@@ -152,4 +152,6 @@ int main()
 
         assert(c0.empty());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_assign_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_assign_noexcept.pass.cpp
index c91d972f3fc..dba99837d07 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_assign_noexcept.pass.cpp
@@ -43,7 +43,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<MoveOnly> C;
@@ -70,4 +70,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_noexcept.pass.cpp
index 86a058b076b..49802f689f3 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/move_noexcept.pass.cpp
@@ -40,7 +40,7 @@ struct some_hash
     std::size_t operator()(T const&) const;
 };
 
-int main()
+int main(int, char**)
 {
 #if defined(_LIBCPP_VERSION)
     {
@@ -67,4 +67,6 @@ int main()
                                                          some_comp<MoveOnly>> C;
         static_assert(!std::is_nothrow_move_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range.pass.cpp
index 182ce8bee4d..dfa46ec5686 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -167,4 +167,6 @@ int main()
 
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size.pass.cpp
index 0c90055eb37..1115044e022 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -100,4 +100,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash.pass.cpp
index 3805b7f32cb..2acbb2d18fa 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -103,4 +103,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal.pass.cpp
index 3fc87223633..245e1247608 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -105,4 +105,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal_allocator.pass.cpp
index 8d73e92dbd4..00246649676 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/range_size_hash_equal_allocator.pass.cpp
@@ -30,7 +30,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<int,
@@ -108,4 +108,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.fail.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.fail.cpp
index 4ed509633e5..da3dc185577 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.fail.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.fail.cpp
@@ -23,7 +23,7 @@
 #include "../../../test_hash.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -42,4 +42,6 @@ int main()
         assert(c.load_factor() == 0);
         assert(c.max_load_factor() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.pass.cpp
index d6377052943..12ba6201a1b 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -62,4 +62,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash.pass.cpp
index 4ded899f6a5..60134b7fad2 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -66,4 +66,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal.pass.cpp
index 36f104dfb9a..49e12ea29d9 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -68,4 +68,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal_allocator.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal_allocator.pass.cpp
index bb14b27a916..43eb1f71703 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal_allocator.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.cnstr/size_hash_equal_allocator.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<NotConstructible,
@@ -70,4 +70,6 @@ int main()
         assert(c.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/db_swap_1.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/db_swap_1.pass.cpp
index 5ea0aa38f75..f14f0ddeb7b 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/db_swap_1.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/db_swap_1.pass.cpp
@@ -21,7 +21,7 @@
 #include <unordered_set>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if _LIBCPP_DEBUG >= 1
     {
@@ -39,4 +39,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp
index 61371306ef0..40bf1894d76 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp
@@ -118,7 +118,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unordered_set<MoveOnly> C;
@@ -186,4 +186,6 @@ int main()
     }
 #endif // _LIBCPP_VERSION
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_non_member.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_non_member.pass.cpp
index aad68658a3b..8f1d9f0c3ee 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_non_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_non_member.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef test_hash<std::hash<int> > Hash;
@@ -566,4 +566,6 @@ int main()
         assert(c2.max_load_factor() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/array.fail.cpp b/libcxx/test/std/containers/views/span.cons/array.fail.cpp
index 7e9d85dcdcb..f6164977187 100644
--- a/libcxx/test/std/containers/views/span.cons/array.fail.cpp
+++ b/libcxx/test/std/containers/views/span.cons/array.fail.cpp
@@ -34,7 +34,7 @@ const          int  carr[] = {4,5,6};
       volatile int  varr[] = {7,8,9};
 const volatile int cvarr[] = {1,3,5};
 
-int main ()
+int main(int, char**)
 {
 //  Size wrong
     {
@@ -68,4 +68,6 @@ int main ()
     std::span<      volatile int,3> s6{ carr};  // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 3>'}}
     std::span<      volatile int,3> s7{cvarr};  // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 3>'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/array.pass.cpp b/libcxx/test/std/containers/views/span.cons/array.pass.cpp
index d9d1029b623..5ac7e1a4a19 100644
--- a/libcxx/test/std/containers/views/span.cons/array.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/array.pass.cpp
@@ -105,7 +105,7 @@ void testRuntimeSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -119,4 +119,6 @@ int main ()
     testRuntimeSpan<A>();
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/assign.pass.cpp b/libcxx/test/std/containers/views/span.cons/assign.pass.cpp
index ea6028ad065..3f8d5f41862 100644
--- a/libcxx/test/std/containers/views/span.cons/assign.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/assign.pass.cpp
@@ -37,7 +37,7 @@ constexpr int carr3[] = {7,8};
 std::string strs[] = {"ABC", "DEF", "GHI"};
 
 
-int main ()
+int main(int, char**)
 {
 
 //  constexpr dynamically sized assignment
@@ -289,4 +289,6 @@ int main ()
             for (size_t j = i; j < std::size(spans); ++j)
                 assert((doAssign(spans[i], spans[j])));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/container.fail.cpp b/libcxx/test/std/containers/views/span.cons/container.fail.cpp
index cfffa57a1e3..d0fb5656d21 100644
--- a/libcxx/test/std/containers/views/span.cons/container.fail.cpp
+++ b/libcxx/test/std/containers/views/span.cons/container.fail.cpp
@@ -63,7 +63,7 @@ private:
 };
 
 
-int main ()
+int main(int, char**)
 {
 
 //  Making non-const spans from const sources (a temporary binds to `const &`)
@@ -129,4 +129,6 @@ int main ()
     std::span<      volatile int,1> s7{cv}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 1>'}}
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/container.pass.cpp b/libcxx/test/std/containers/views/span.cons/container.pass.cpp
index 4e9001bff8d..07aac9229f0 100644
--- a/libcxx/test/std/containers/views/span.cons/container.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/container.pass.cpp
@@ -117,7 +117,7 @@ void testRuntimeSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -131,4 +131,6 @@ int main ()
     testRuntimeSpan<A>();
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/copy.pass.cpp b/libcxx/test/std/containers/views/span.cons/copy.pass.cpp
index 1ccb679ce94..2ad1cded216 100644
--- a/libcxx/test/std/containers/views/span.cons/copy.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/copy.pass.cpp
@@ -42,7 +42,7 @@ void testCV ()
 }
 
 
-int main ()
+int main(int, char**)
 {
     constexpr int carr[] = {1,2,3};
 
@@ -67,4 +67,6 @@ int main ()
     testCV<const          int>();
     testCV<      volatile int>();
     testCV<const volatile int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/deduct.pass.cpp b/libcxx/test/std/containers/views/span.cons/deduct.pass.cpp
index 7c533883658..188463bc31f 100644
--- a/libcxx/test/std/containers/views/span.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/deduct.pass.cpp
@@ -40,7 +40,7 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
-int main ()
+int main(int, char**)
 {
     {
     int arr[] = {1,2,3};
@@ -83,4 +83,6 @@ int main ()
     assert((size_t)s.size() == str.size());
     assert((std::equal(s.begin(), s.end(), std::begin(s), std::end(s))));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/default.fail.cpp b/libcxx/test/std/containers/views/span.cons/default.fail.cpp
index 309f7180c18..24ff77477bd 100644
--- a/libcxx/test/std/containers/views/span.cons/default.fail.cpp
+++ b/libcxx/test/std/containers/views/span.cons/default.fail.cpp
@@ -22,10 +22,12 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::span<int, 2> s; // expected-error-re@span:* {{static_assert failed{{( due to requirement '2[LL]{0,2} == 0')?}} "Can't default construct a statically sized span with size > 0"}}
 
 //  TODO: This is what I want:
 // eXpected-error {{no matching constructor for initialization of 'std::span<int, 2>'}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/default.pass.cpp b/libcxx/test/std/containers/views/span.cons/default.pass.cpp
index 431b7e90baf..867026bd9ae 100644
--- a/libcxx/test/std/containers/views/span.cons/default.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/default.pass.cpp
@@ -64,7 +64,7 @@ void testRuntimeSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -78,4 +78,6 @@ int main ()
     testRuntimeSpan<A>();
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/ptr_len.fail.cpp b/libcxx/test/std/containers/views/span.cons/ptr_len.fail.cpp
index ad63c69b3ea..d407ae77936 100644
--- a/libcxx/test/std/containers/views/span.cons/ptr_len.fail.cpp
+++ b/libcxx/test/std/containers/views/span.cons/ptr_len.fail.cpp
@@ -27,7 +27,7 @@ const          int  carr[] = {4,5,6};
       volatile int  varr[] = {7,8,9};
 const volatile int cvarr[] = {1,3,5};
 
-int main ()
+int main(int, char**)
 {
 //  We can't check that the size doesn't match - because that's a runtime property
 //  std::span<int, 2>   s1(arr, 3);
@@ -59,4 +59,6 @@ int main ()
     std::span<      volatile int,3> s6{ carr, 3};   // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 3>'}}
     std::span<      volatile int,3> s7{cvarr, 3};   // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 3>'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/ptr_len.pass.cpp b/libcxx/test/std/containers/views/span.cons/ptr_len.pass.cpp
index a1a93c71fab..2a4b260c87d 100644
--- a/libcxx/test/std/containers/views/span.cons/ptr_len.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/ptr_len.pass.cpp
@@ -95,7 +95,7 @@ void testRuntimeSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -109,4 +109,6 @@ int main ()
     testRuntimeSpan<A>();
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/ptr_ptr.fail.cpp b/libcxx/test/std/containers/views/span.cons/ptr_ptr.fail.cpp
index 0bda60c3f02..9c15ea58c95 100644
--- a/libcxx/test/std/containers/views/span.cons/ptr_ptr.fail.cpp
+++ b/libcxx/test/std/containers/views/span.cons/ptr_ptr.fail.cpp
@@ -27,7 +27,7 @@ const          int  carr[] = {4,5,6};
       volatile int  varr[] = {7,8,9};
 const volatile int cvarr[] = {1,3,5};
 
-int main ()
+int main(int, char**)
 {
 //  We can't check that the size doesn't match - because that's a runtime property
 //  std::span<int, 2>   s1(arr, arr + 3);
@@ -59,4 +59,6 @@ int main ()
     std::span<      volatile int,3> s6{ carr,  carr + 3};   // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 3>'}}
     std::span<      volatile int,3> s7{cvarr, cvarr + 3};   // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 3>'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/ptr_ptr.pass.cpp b/libcxx/test/std/containers/views/span.cons/ptr_ptr.pass.cpp
index 1d693e39244..15c9f303ecb 100644
--- a/libcxx/test/std/containers/views/span.cons/ptr_ptr.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/ptr_ptr.pass.cpp
@@ -95,7 +95,7 @@ void testRuntimeSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -109,4 +109,6 @@ int main ()
     testRuntimeSpan<A>();
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/span.fail.cpp b/libcxx/test/std/containers/views/span.cons/span.fail.cpp
index 132d1b15226..f559b1fb0c2 100644
--- a/libcxx/test/std/containers/views/span.cons/span.fail.cpp
+++ b/libcxx/test/std/containers/views/span.cons/span.fail.cpp
@@ -89,7 +89,7 @@ void checkCV ()
     }
 }
 
-int main ()
+int main(int, char**)
 {
     std::span<int>      sp;
     std::span<int, 0>   sp0;
@@ -100,4 +100,6 @@ int main ()
     std::span<float, 0> s4{sp0};    // expected-error {{no matching constructor for initialization of 'std::span<float, 0>'}}
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/span.pass.cpp b/libcxx/test/std/containers/views/span.cons/span.pass.cpp
index 8ace94f5e05..74da3fce894 100644
--- a/libcxx/test/std/containers/views/span.cons/span.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/span.pass.cpp
@@ -121,7 +121,7 @@ bool testConversionSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -138,4 +138,6 @@ int main ()
 //  assert((testConversionSpan<unsigned char, char>()));
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp b/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp
index a0b37fe8e64..03fdd253426 100644
--- a/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp
@@ -96,7 +96,7 @@ void testRuntimeSpan()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan<int>(),    "");
     static_assert(testConstexprSpan<long>(),   "");
@@ -110,4 +110,6 @@ int main ()
     testRuntimeSpan<A>();
 
     checkCV();
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.elem/data.pass.cpp b/libcxx/test/std/containers/views/span.elem/data.pass.cpp
index ca49eb8900a..c858a7e11e3 100644
--- a/libcxx/test/std/containers/views/span.elem/data.pass.cpp
+++ b/libcxx/test/std/containers/views/span.elem/data.pass.cpp
@@ -40,7 +40,7 @@ struct A{};
 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
-int main ()
+int main(int, char**)
 {
 
 //  dynamic size
@@ -117,4 +117,6 @@ int main ()
     testRuntimeSpan(std::span<std::string>(&s, 1), &s);
     testRuntimeSpan(std::span<std::string, 1>(&s, 1), &s);
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.elem/op_idx.pass.cpp b/libcxx/test/std/containers/views/span.elem/op_idx.pass.cpp
index d11032673fb..c56be7d3e2c 100644
--- a/libcxx/test/std/containers/views/span.elem/op_idx.pass.cpp
+++ b/libcxx/test/std/containers/views/span.elem/op_idx.pass.cpp
@@ -51,7 +51,7 @@ struct A{};
 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<const int>(iArr1, 1), 0), "");
 
@@ -115,4 +115,6 @@ int main ()
     std::string s;
     testRuntimeSpan(std::span<std::string>   (&s, 1), 0);
     testRuntimeSpan(std::span<std::string, 1>(&s, 1), 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.iterators/begin.pass.cpp b/libcxx/test/std/containers/views/span.iterators/begin.pass.cpp
index 0abae63ff2f..e4532ade54e 100644
--- a/libcxx/test/std/containers/views/span.iterators/begin.pass.cpp
+++ b/libcxx/test/std/containers/views/span.iterators/begin.pass.cpp
@@ -70,7 +70,7 @@ constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
 
-int main()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<int>()),            "");
     static_assert(testConstexprSpan(std::span<long>()),           "");
@@ -112,4 +112,6 @@ int main()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.iterators/end.pass.cpp b/libcxx/test/std/containers/views/span.iterators/end.pass.cpp
index a834804d176..c52c8bc6004 100644
--- a/libcxx/test/std/containers/views/span.iterators/end.pass.cpp
+++ b/libcxx/test/std/containers/views/span.iterators/end.pass.cpp
@@ -78,7 +78,7 @@ constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
 
-int main()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<int>()),            "");
     static_assert(testConstexprSpan(std::span<long>()),           "");
@@ -120,4 +120,6 @@ int main()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.iterators/rbegin.pass.cpp b/libcxx/test/std/containers/views/span.iterators/rbegin.pass.cpp
index 66e1d5ebf96..fc7d3c8e006 100644
--- a/libcxx/test/std/containers/views/span.iterators/rbegin.pass.cpp
+++ b/libcxx/test/std/containers/views/span.iterators/rbegin.pass.cpp
@@ -71,7 +71,7 @@ constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
 
-int main()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<int>()),            "");
     static_assert(testConstexprSpan(std::span<long>()),           "");
@@ -113,4 +113,6 @@ int main()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, static_cast<std::ptrdiff_t>(0)));
     testRuntimeSpan(std::span<std::string>(&s, 1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.iterators/rend.pass.cpp b/libcxx/test/std/containers/views/span.iterators/rend.pass.cpp
index 7c53cb0becd..056fe2a7d2b 100644
--- a/libcxx/test/std/containers/views/span.iterators/rend.pass.cpp
+++ b/libcxx/test/std/containers/views/span.iterators/rend.pass.cpp
@@ -72,7 +72,7 @@ constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
 
-int main()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<int>()),            "");
     static_assert(testConstexprSpan(std::span<long>()),           "");
@@ -114,4 +114,6 @@ int main()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp b/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
index 989b6dc5cb6..3e6a7d79ffd 100644
--- a/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
+++ b/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
@@ -45,7 +45,7 @@ void testRuntimeSpan(Span sp)
 struct A{};
 int iArr2[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
 
-int main ()
+int main(int, char**)
 {
     testRuntimeSpan(std::span<int>        ());
     testRuntimeSpan(std::span<long>       ());
@@ -74,4 +74,6 @@ int main ()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp b/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp
index 9b0034b9b58..b987edb30a5 100644
--- a/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp
+++ b/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp
@@ -28,7 +28,7 @@ const int iArr2[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
 
 struct A {};
 
-int main ()
+int main(int, char**)
 {
     std::as_writeable_bytes(std::span<const int>());            // expected-error {{no matching function for call to 'as_writeable_bytes'}}
     std::as_writeable_bytes(std::span<const long>());           // expected-error {{no matching function for call to 'as_writeable_bytes'}}
@@ -44,4 +44,6 @@ int main ()
 
     std::as_writeable_bytes(std::span<const int>   (iArr2, 1));     // expected-error {{no matching function for call to 'as_writeable_bytes'}}
     std::as_writeable_bytes(std::span<const int, 1>(iArr2 + 5, 1)); // expected-error {{no matching function for call to 'as_writeable_bytes'}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp b/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp
index 6538a59465a..96bb40ec49b 100644
--- a/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp
+++ b/libcxx/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp
@@ -45,7 +45,7 @@ void testRuntimeSpan(Span sp)
 struct A{};
 int iArr2[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
 
-int main ()
+int main(int, char**)
 {
     testRuntimeSpan(std::span<int>        ());
     testRuntimeSpan(std::span<long>       ());
@@ -74,4 +74,6 @@ int main ()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.obs/empty.pass.cpp b/libcxx/test/std/containers/views/span.obs/empty.pass.cpp
index e0cdb141b1e..9db8c8ab71c 100644
--- a/libcxx/test/std/containers/views/span.obs/empty.pass.cpp
+++ b/libcxx/test/std/containers/views/span.obs/empty.pass.cpp
@@ -24,7 +24,7 @@ struct A{};
 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
-int main ()
+int main(int, char**)
 {
     static_assert( noexcept(std::span<int>   ().empty()), "");
     static_assert( noexcept(std::span<int, 0>().empty()), "");
@@ -69,4 +69,6 @@ int main ()
     std::string s;
     assert( ((std::span<std::string>(&s, (std::ptrdiff_t) 0)).empty()));
     assert(!((std::span<std::string>(&s, 1).empty())));
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.obs/size.pass.cpp b/libcxx/test/std/containers/views/span.obs/size.pass.cpp
index 0dc1dd268f8..f1dbc1fd99e 100644
--- a/libcxx/test/std/containers/views/span.obs/size.pass.cpp
+++ b/libcxx/test/std/containers/views/span.obs/size.pass.cpp
@@ -40,7 +40,7 @@ struct A{};
 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<int>(), 0),            "");
     static_assert(testConstexprSpan(std::span<long>(), 0),           "");
@@ -87,4 +87,6 @@ int main ()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0), 0);
     testRuntimeSpan(std::span<std::string>(&s, 1), 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.obs/size_bytes.pass.cpp b/libcxx/test/std/containers/views/span.obs/size_bytes.pass.cpp
index fa26a408f30..1d423527cd0 100644
--- a/libcxx/test/std/containers/views/span.obs/size_bytes.pass.cpp
+++ b/libcxx/test/std/containers/views/span.obs/size_bytes.pass.cpp
@@ -41,7 +41,7 @@ struct A{};
 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
 
-int main ()
+int main(int, char**)
 {
     static_assert(testConstexprSpan(std::span<int>(), 0),            "");
     static_assert(testConstexprSpan(std::span<long>(), 0),           "");
@@ -88,4 +88,6 @@ int main ()
     std::string s;
     testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0), 0);
     testRuntimeSpan(std::span<std::string>(&s, 1), 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.sub/first.pass.cpp b/libcxx/test/std/containers/views/span.sub/first.pass.cpp
index 7d66884280a..f9da9fdc233 100644
--- a/libcxx/test/std/containers/views/span.sub/first.pass.cpp
+++ b/libcxx/test/std/containers/views/span.sub/first.pass.cpp
@@ -68,7 +68,7 @@ constexpr int carr1[] = {1,2,3,4};
           int   arr[] = {5,6,7};
 std::string   sarr [] = { "ABC", "DEF", "GHI", "JKL", "MNO"};
 
-int main ()
+int main(int, char**)
 {
     {
     using Sp = std::span<const int>;
@@ -132,4 +132,6 @@ int main ()
     testRuntimeSpan<Sp, 4>(Sp{sarr});
     testRuntimeSpan<Sp, 5>(Sp{sarr});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.sub/last.pass.cpp b/libcxx/test/std/containers/views/span.sub/last.pass.cpp
index 17155604776..e0a399ff9cd 100644
--- a/libcxx/test/std/containers/views/span.sub/last.pass.cpp
+++ b/libcxx/test/std/containers/views/span.sub/last.pass.cpp
@@ -68,7 +68,7 @@ constexpr int carr1[] = {1,2,3,4};
           int   arr[] = {5,6,7};
 std::string   sarr [] = { "ABC", "DEF", "GHI", "JKL", "MNO"};
 
-int main ()
+int main(int, char**)
 {
     {
     using Sp = std::span<const int>;
@@ -132,4 +132,6 @@ int main ()
     testRuntimeSpan<Sp, 4>(Sp{sarr});
     testRuntimeSpan<Sp, 5>(Sp{sarr});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/span.sub/subspan.pass.cpp b/libcxx/test/std/containers/views/span.sub/subspan.pass.cpp
index 22446adbbd6..9cb73109347 100644
--- a/libcxx/test/std/containers/views/span.sub/subspan.pass.cpp
+++ b/libcxx/test/std/containers/views/span.sub/subspan.pass.cpp
@@ -106,7 +106,7 @@ void testRuntimeSpan(Span sp)
 constexpr int carr1[] = {1,2,3,4};
           int  arr1[] = {5,6,7};
 
-int main ()
+int main(int, char**)
 {
     {
     using Sp = std::span<const int>;
@@ -206,4 +206,6 @@ int main ()
     testRuntimeSpan<Sp, 2>(Sp{arr1});
     testRuntimeSpan<Sp, 3>(Sp{arr1});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/containers/views/types.pass.cpp b/libcxx/test/std/containers/views/types.pass.cpp
index e8ddbed161f..ac6f47fa8e5 100644
--- a/libcxx/test/std/containers/views/types.pass.cpp
+++ b/libcxx/test/std/containers/views/types.pass.cpp
@@ -96,11 +96,13 @@ void test()
 
 struct A{};
 
-int main ()
+int main(int, char**)
 {
     test<int>();
     test<long>();
     test<double>();
     test<std::string>();
     test<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.fail.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.fail.cpp
index 1b2d9043fba..2fa102e2783 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.fail.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.fail.cpp
@@ -37,7 +37,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.pass.cpp
index a8899e103fd..31eb1f67db7 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/assignment.pass.cpp
@@ -39,7 +39,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.fail.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.fail.cpp
index 9e7505acdd7..2a7fe6640b2 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.fail.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.fail.cpp
@@ -33,7 +33,9 @@ test()
     assert(B::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.pass.cpp
index eccfad4cb5f..3d574de342a 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert.pass.cpp
@@ -35,7 +35,9 @@ test()
     assert(B::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.fail.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.fail.cpp
index c3abdf01062..23f6a19995b 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.fail.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.fail.cpp
@@ -40,7 +40,9 @@ test()
     assert(B::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.pass.cpp
index 5704f8db076..dc363c1e9a7 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/convert_assignment.pass.cpp
@@ -42,7 +42,9 @@ test()
     assert(B::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.fail.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.fail.cpp
index 9efb9cdb6ee..3684da49352 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.fail.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.fail.cpp
@@ -31,7 +31,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.pass.cpp
index 6c9c476cd19..0e674f21a34 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/copy.pass.cpp
@@ -33,7 +33,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/explicit.fail.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/explicit.fail.cpp
index 7e75911ffa7..e91abaf5a1b 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/explicit.fail.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/explicit.fail.cpp
@@ -33,7 +33,9 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/pointer.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/pointer.pass.cpp
index 400126e4ab4..7423c3b73f3 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/pointer.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.cons/pointer.pass.cpp
@@ -35,7 +35,9 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/assign_from_auto_ptr_ref.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/assign_from_auto_ptr_ref.pass.cpp
index 0b5b9c5da0b..0486e02fb83 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/assign_from_auto_ptr_ref.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/assign_from_auto_ptr_ref.pass.cpp
@@ -35,7 +35,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_from_auto_ptr_ref.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_from_auto_ptr_ref.pass.cpp
index 2e08decfa7d..7dd37f76026 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_from_auto_ptr_ref.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_from_auto_ptr_ref.pass.cpp
@@ -34,7 +34,9 @@ test()
     assert(B::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr.pass.cpp
index 554ce3165b8..809f6b37e17 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr.pass.cpp
@@ -31,7 +31,9 @@ test()
     std::auto_ptr<A> ap2(source());
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr_ref.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr_ref.pass.cpp
index bcb7d61c985..a75f1349236 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr_ref.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.conv/convert_to_auto_ptr_ref.pass.cpp
@@ -32,7 +32,9 @@ test()
     delete p1;
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/arrow.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/arrow.pass.cpp
index c10beec7967..7878f50f7a9 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/arrow.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/arrow.pass.cpp
@@ -32,7 +32,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/deref.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/deref.pass.cpp
index 271b4ffb496..1e41c8a9dab 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/deref.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/deref.pass.cpp
@@ -32,7 +32,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/release.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/release.pass.cpp
index 2cd0faf2736..61b6bbcc692 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/release.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/release.pass.cpp
@@ -33,7 +33,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/reset.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/reset.pass.cpp
index c74cabf79f3..d2ebd5668e9 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/reset.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/auto.ptr.members/reset.pass.cpp
@@ -49,7 +49,9 @@ test()
     assert(A::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/element_type.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/element_type.pass.cpp
index 36e59dd0fa5..a4dac761526 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/element_type.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/auto.ptr/element_type.pass.cpp
@@ -30,9 +30,11 @@ test()
     ((void)p);
 }
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<double>();
     test<void>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.auto.ptr/nothing_to_do.pass.cpp b/libcxx/test/std/depr/depr.auto.ptr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/depr/depr.auto.ptr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/depr/depr.auto.ptr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/assert_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/assert_h.pass.cpp
index aee59570a8c..d680f33efcc 100644
--- a/libcxx/test/std/depr/depr.c.headers/assert_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/assert_h.pass.cpp
@@ -14,6 +14,8 @@
 #error assert not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/ciso646.pass.cpp b/libcxx/test/std/depr/depr.c.headers/ciso646.pass.cpp
index 2f962bc8b6e..3eb4064e69e 100644
--- a/libcxx/test/std/depr/depr.c.headers/ciso646.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/ciso646.pass.cpp
@@ -10,6 +10,8 @@
 
 #include <ciso646>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/complex.h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/complex.h.pass.cpp
index 6502bb66965..d92ddb67b0e 100644
--- a/libcxx/test/std/depr/depr.c.headers/complex.h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/complex.h.pass.cpp
@@ -10,8 +10,10 @@
 
 #include <complex.h>
 
-int main()
+int main(int, char**)
 {
     std::complex<double> d;
     (void)d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/ctype_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/ctype_h.pass.cpp
index 7c7c83a8367..61b539d4093 100644
--- a/libcxx/test/std/depr/depr.c.headers/ctype_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/ctype_h.pass.cpp
@@ -68,7 +68,7 @@
 #error toupper defined
 #endif
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<decltype(isalnum(0)), int>::value), "");
     static_assert((std::is_same<decltype(isalpha(0)), int>::value), "");
@@ -99,4 +99,6 @@ int main()
     assert(isxdigit('a'));
     assert(tolower('A') == 'a');
     assert(toupper('a') == 'A');
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/errno_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/errno_h.pass.cpp
index 51ad3fe7c9f..985cdc7f5c4 100644
--- a/libcxx/test/std/depr/depr.c.headers/errno_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/errno_h.pass.cpp
@@ -27,6 +27,8 @@
 #error errno not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/fenv_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/fenv_h.pass.cpp
index b6c2549b5cb..3a6f63c3fc3 100644
--- a/libcxx/test/std/depr/depr.c.headers/fenv_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/fenv_h.pass.cpp
@@ -57,7 +57,7 @@
 #error FE_DFL_ENV not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     fenv_t fenv = {};
     fexcept_t fex = 0;
@@ -72,4 +72,6 @@ int main()
     static_assert((std::is_same<decltype(feholdexcept(&fenv)), int>::value), "");
     static_assert((std::is_same<decltype(fesetenv(&fenv)), int>::value), "");
     static_assert((std::is_same<decltype(feupdateenv(&fenv)), int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/float_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/float_h.pass.cpp
index 3e73b385de7..779fbc66f5d 100644
--- a/libcxx/test/std/depr/depr.c.headers/float_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/float_h.pass.cpp
@@ -178,6 +178,8 @@
 #endif
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/inttypes_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/inttypes_h.pass.cpp
index 6db3a42f184..a088733119e 100644
--- a/libcxx/test/std/depr/depr.c.headers/inttypes_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/inttypes_h.pass.cpp
@@ -877,7 +877,7 @@ template <class T> void test()
     ((void)t); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test<int8_t >();
     test<int16_t>();
@@ -927,4 +927,6 @@ int main()
     static_assert((std::is_same<decltype(strtoumax("", (char**)0, 0)), uintmax_t>::value), "");
     static_assert((std::is_same<decltype(wcstoimax(L"", (wchar_t**)0, 0)), intmax_t>::value), "");
     static_assert((std::is_same<decltype(wcstoumax(L"", (wchar_t**)0, 0)), uintmax_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/iso646_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/iso646_h.pass.cpp
index dee560858a0..77ca126278d 100644
--- a/libcxx/test/std/depr/depr.c.headers/iso646_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/iso646_h.pass.cpp
@@ -10,7 +10,9 @@
 
 #include <iso646.h>
 
-int main()
+int main(int, char**)
 {
     // Nothing to test
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/limits_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/limits_h.pass.cpp
index a8ad39215be..5dba10edfb7 100644
--- a/libcxx/test/std/depr/depr.c.headers/limits_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/limits_h.pass.cpp
@@ -86,6 +86,8 @@
 #error ULLONG_MAX not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/locale_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/locale_h.pass.cpp
index 9774dd6e83d..fd2419bb707 100644
--- a/libcxx/test/std/depr/depr.c.headers/locale_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/locale_h.pass.cpp
@@ -39,9 +39,11 @@
 #error NULL not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     lconv lc; ((void)lc);
     static_assert((std::is_same<decltype(setlocale(0, "")), char*>::value), "");
     static_assert((std::is_same<decltype(localeconv()), lconv*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/math_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/math_h.pass.cpp
index 56259710625..b0b6c0cb324 100644
--- a/libcxx/test/std/depr/depr.c.headers/math_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/math_h.pass.cpp
@@ -1463,7 +1463,7 @@ void test_trunc()
     assert(trunc(1) == 1);
 }
 
-int main()
+int main(int, char**)
 {
     test_abs();
     test_acos();
@@ -1535,4 +1535,6 @@ int main()
     test_scalbn();
     test_tgamma();
     test_trunc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/setjmp_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/setjmp_h.pass.cpp
index 3c8584b1b2f..1878f4f8470 100644
--- a/libcxx/test/std/depr/depr.c.headers/setjmp_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/setjmp_h.pass.cpp
@@ -15,10 +15,12 @@
 #error setjmp not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     jmp_buf jb;
     ((void)jb); // Prevent unused warning
     static_assert((std::is_same<decltype(longjmp(jb, 0)), void>::value),
                   "std::is_same<decltype(longjmp(jb, 0)), void>::value");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/signal_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/signal_h.pass.cpp
index e2fc456e44c..463d670ba1e 100644
--- a/libcxx/test/std/depr/depr.c.headers/signal_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/signal_h.pass.cpp
@@ -47,10 +47,12 @@
 #error SIGTERM not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     sig_atomic_t sig; ((void)sig);
     typedef void (*func)(int);
     static_assert((std::is_same<decltype(signal(0, (func)0)), func>::value), "");
     static_assert((std::is_same<decltype(raise(0)), int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/stdarg_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdarg_h.pass.cpp
index a336fe59f4b..feb9c4a460f 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdarg_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdarg_h.pass.cpp
@@ -30,8 +30,10 @@
 #error va_start not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     va_list va;
     ((void)va);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/stdbool_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdbool_h.pass.cpp
index 38dfc6d8496..132ad9c5cd9 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdbool_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdbool_h.pass.cpp
@@ -26,6 +26,8 @@
 #error false should not be defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp
index 8c420de52e3..c54c976ee09 100644
--- a/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp
@@ -22,7 +22,7 @@
 #error offsetof not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     void *p = NULL;
     assert(!p);
@@ -65,4 +65,6 @@ int main()
                   std::alignment_of<void*>::value,
                   "std::alignment_of<max_align_t>::value >= "
                   "std::alignment_of<void*>::value");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/stdint_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdint_h.pass.cpp
index e031e21036d..68efe7992af 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdint_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdint_h.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     // typedef int8_t
     static_assert(sizeof(int8_t)*CHAR_BIT == 8,
@@ -287,4 +287,6 @@ int main()
 #ifndef UINTMAX_C
 #error UINTMAX_C not defined
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/stdio_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdio_h.pass.cpp
index b60279696c0..97ea0d41519 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdio_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdio_h.pass.cpp
@@ -103,7 +103,7 @@
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" // for tmpnam
 #endif
 
-int main()
+int main(int, char**)
 {
     FILE* fp = 0;
     fpos_t fpos = fpos_t();
@@ -165,4 +165,6 @@ int main()
     static_assert((std::is_same<decltype(feof(fp)), int>::value), "");
     static_assert((std::is_same<decltype(ferror(fp)), int>::value), "");
     static_assert((std::is_same<decltype(perror("")), void>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
index c035cf046a7..4c0218d6ef6 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
@@ -63,7 +63,7 @@
 #error RAND_MAX not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     size_t s = 0; ((void)s);
     div_t d; ((void)d);
@@ -116,4 +116,6 @@ int main()
     static_assert((std::is_same<decltype(wctomb(pc,L' ')), int>::value), "");
     static_assert((std::is_same<decltype(mbstowcs(pw,"",0)), size_t>::value), "");
     static_assert((std::is_same<decltype(wcstombs(pc,pwc,0)), size_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/string_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/string_h.pass.cpp
index 62c552b9bec..8ed1513b356 100644
--- a/libcxx/test/std/depr/depr.c.headers/string_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/string_h.pass.cpp
@@ -15,7 +15,7 @@
 #error NULL not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     size_t s = 0;
     void* vp = 0;
@@ -57,4 +57,6 @@ int main()
     static_assert((std::is_same<decltype(strstr(cpc, cpc)), const char*>::value), "");
     static_assert((std::is_same<decltype(memchr(vpc, 0, s)), const void*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/tgmath_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/tgmath_h.pass.cpp
index e9c48060508..28cf93ada0a 100644
--- a/libcxx/test/std/depr/depr.c.headers/tgmath_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/tgmath_h.pass.cpp
@@ -10,10 +10,12 @@
 
 #include <tgmath.h>
 
-int main()
+int main(int, char**)
 {
     std::complex<double> cd;
     (void)cd;
     double x = sin(1.0);
     (void)x; // to placate scan-build
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/time_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/time_h.pass.cpp
index eb9565128eb..5c2cc57bc69 100644
--- a/libcxx/test/std/depr/depr.c.headers/time_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/time_h.pass.cpp
@@ -19,7 +19,7 @@
 #error CLOCKS_PER_SEC not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     clock_t c = 0; ((void)c);
     size_t s = 0;
@@ -36,4 +36,6 @@ int main()
     char* c1 = 0;
     const char* c2 = 0;
     static_assert((std::is_same<decltype(strftime(c1,s,c2,&tmv)), size_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/uchar_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/uchar_h.pass.cpp
index bff39d2c855..cddf7a284a3 100644
--- a/libcxx/test/std/depr/depr.c.headers/uchar_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/uchar_h.pass.cpp
@@ -15,6 +15,8 @@
 
 #include <uchar.h>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/wchar_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/wchar_h.pass.cpp
index 6072159952c..b964ea76f94 100644
--- a/libcxx/test/std/depr/depr.c.headers/wchar_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/wchar_h.pass.cpp
@@ -28,7 +28,7 @@
 #error WEOF not defined
 #endif
 
-int main()
+int main(int, char**)
 {
 // mbstate_t comes from the underlying C library; it is defined (in C99) as:
 //    a complete object type other than an array type that can hold the conversion
@@ -126,4 +126,6 @@ int main()
     static_assert((std::is_same<decltype(vwprintf(L"", va)), int>::value), "");
     static_assert((std::is_same<decltype(wprintf(L"")), int>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.c.headers/wctype_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/wctype_h.pass.cpp
index f4dc1bf4f7a..1774a7f0897 100644
--- a/libcxx/test/std/depr/depr.c.headers/wctype_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/wctype_h.pass.cpp
@@ -87,7 +87,7 @@
 #error wctrans defined
 #endif
 
-int main()
+int main(int, char**)
 {
     wint_t w = 0;
     wctrans_t wctr = 0;
@@ -110,4 +110,6 @@ int main()
     static_assert((std::is_same<decltype(towupper(w)), wint_t>::value), "");
     static_assert((std::is_same<decltype(towctrans(w, wctr)), wint_t>::value), "");
     static_assert((std::is_same<decltype(wctrans("")), wctrans_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.cxx1z.fail.cpp
index 062bbaee8da..feb345b9ae5 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.cxx1z.fail.cpp
@@ -18,7 +18,9 @@
 
 double binary_f(int i, short j) {return i - j + .75;}
 
-int main()
+int main(int, char**)
 {
     typedef std::pointer_to_binary_function<int, short, double> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.pass.cpp
index 8d099e52ca7..53df5f34832 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_binary_function.pass.cpp
@@ -17,10 +17,12 @@
 
 double binary_f(int i, short j) {return i - j + .75;}
 
-int main()
+int main(int, char**)
 {
     typedef std::pointer_to_binary_function<int, short, double> F;
     static_assert((std::is_base_of<std::binary_function<int, short, double>, F>::value), "");
     const F f(binary_f);
     assert(f(36, 27) == 9.75);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.cxx1z.fail.cpp
index cc3bb6dcf0e..9d2d891bb2c 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.cxx1z.fail.cpp
@@ -18,7 +18,9 @@
 
 double unary_f(int i) {return 0.5 - i;}
 
-int main()
+int main(int, char**)
 {
     typedef std::pointer_to_unary_function<int, double> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.pass.cpp
index e039fb4c60a..776fd309b56 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/pointer_to_unary_function.pass.cpp
@@ -17,10 +17,12 @@
 
 double unary_f(int i) {return 0.5 - i;}
 
-int main()
+int main(int, char**)
 {
     typedef std::pointer_to_unary_function<int, double> F;
     static_assert((std::is_base_of<std::unary_function<int, double>, F>::value), "");
     const F f(unary_f);
     assert(f(36) == -35.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.cxx1z.fail.cpp
index 3efe3db5638..e0e7889e91f 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.cxx1z.fail.cpp
@@ -21,7 +21,9 @@
 
 double unary_f(int i) {return 0.5 - i;}
 
-int main()
+int main(int, char**)
 {
     assert(std::ptr_fun(unary_f)(36) == -35.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.pass.cpp
index 323a559815c..b356be2e90c 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun1.pass.cpp
@@ -19,7 +19,9 @@
 
 double unary_f(int i) {return 0.5 - i;}
 
-int main()
+int main(int, char**)
 {
     assert(std::ptr_fun(unary_f)(36) == -35.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.cxx1z.fail.cpp
index d1ad2636264..d975072966e 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.cxx1z.fail.cpp
@@ -21,7 +21,9 @@
 
 double binary_f(int i, short j) {return i - j + .75;}
 
-int main()
+int main(int, char**)
 {
     assert(std::ptr_fun(binary_f)(36, 27) == 9.75);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.pass.cpp
index 1bffccff58f..885f7db67a4 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.function.pointer.adaptors/ptr_fun2.pass.cpp
@@ -19,7 +19,9 @@
 
 double binary_f(int i, short j) {return i - j + .75;}
 
-int main()
+int main(int, char**)
 {
     assert(std::ptr_fun(binary_f)(36, 27) == 9.75);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.cxx1z.fail.cpp
index 86cc02ec3dd..e346f07ccb8 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun(&A::a3)(&a) == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.pass.cpp
index f4a73e75362..d7052ee5a33 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun(&A::a3)(&a) == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.cxx1z.fail.cpp
index 4f1e0aa70c6..e489a558ebd 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun(&A::a4)(&a, 6) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.pass.cpp
index 6f89ec1802b..f3c35f257f5 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun(&A::a4)(&a, 6) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.cxx1z.fail.cpp
index 903e13c9755..14368e6e9e6 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun1_ref_t<double, A, unsigned> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.pass.cpp
index 6e6c60d60fb..50782e09aa4 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_ref_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun1_ref_t<double, A, unsigned> F;
     static_assert((std::is_base_of<std::binary_function<A, unsigned, double>, F>::value), "");
     const F f(&A::a4);
     const A a = A();
     assert(f(a, 6) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.cxx1z.fail.cpp
index 242c977a2be..afa0b781ffc 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun1_t<double, A, unsigned> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.pass.cpp
index f4a78729e65..cf0218e8f9f 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun1_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun1_t<double, A, unsigned> F;
     static_assert((std::is_base_of<std::binary_function<const A*, unsigned, double>, F>::value), "");
     const F f(&A::a4);
     const A a = A();
     assert(f(&a, 6) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.cxx1z.fail.cpp
index 93322099da0..1217cfe597b 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun_ref(&A::a3)(a) == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.pass.cpp
index 5f05821c864..7765319908c 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun_ref(&A::a3)(a) == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.cxx1z.fail.cpp
index 44eee11be20..58251d13092 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun_ref(&A::a4)(a, 6) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.pass.cpp
index 55586a91fc3..4015675f8f4 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref1.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     const A a = A();
     assert(std::mem_fun_ref(&A::a4)(a, 6) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.cxx1z.fail.cpp
index eac5820624b..577cfe53760 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun_ref_t<int, A> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.pass.cpp
index 3654ec2f196..61382dc40f8 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_ref_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun_ref_t<int, A> F;
     static_assert((std::is_base_of<std::unary_function<A, int>, F>::value), "");
     const F f(&A::a3);
     const A a = A();
     assert(f(a) == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.cxx1z.fail.cpp
index 824cdf9adb7..ee24e4116a1 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun_t<int, A> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.pass.cpp
index 2814dccf844..ca1065abfe8 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/const_mem_fun_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::const_mem_fun_t<int, A> F;
     static_assert((std::is_base_of<std::unary_function<const A*, int>, F>::value), "");
     const F f(&A::a3);
     const A a = A();
     assert(f(&a) == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.cxx1z.fail.cpp
index d54896c55a3..a000ac5ee2f 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun(&A::a1)(&a) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.pass.cpp
index e1bbb65d68b..6b707c4ad19 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun(&A::a1)(&a) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.cxx1z.fail.cpp
index c4f9dcb4ebc..626c9102e5c 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun(&A::a2)(&a, 5) == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.pass.cpp
index d5261e211a4..5abf157a6ce 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun(&A::a2)(&a, 5) == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.cxx1z.fail.cpp
index 653ea21479b..4ac39e76421 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun1_ref_t<short, A, int> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.pass.cpp
index 416c20856c3..ec21c42c9b6 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_ref_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun1_ref_t<short, A, int> F;
     static_assert((std::is_base_of<std::binary_function<A, int, short>, F>::value), "");
     const F f(&A::a2);
     A a;
     assert(f(a, 5) == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.cxx1z.fail.cpp
index 3d77237a203..6471f8e9153 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun1_t<short, A, int> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.pass.cpp
index 8403d471d68..d696bae067e 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun1_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun1_t<short, A, int> F;
     static_assert((std::is_base_of<std::binary_function<A*, int, short>, F>::value), "");
     const F f(&A::a2);
     A a;
     assert(f(&a, 5) == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.cxx1z.fail.cpp
index 4eaa53eeee9..e6227509fb0 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun_ref(&A::a1)(a) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.pass.cpp
index 6ceff9257c0..e22a7f03d03 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun_ref(&A::a1)(a) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.cxx1z.fail.cpp
index 2a73da49eab..c633e769dd6 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.cxx1z.fail.cpp
@@ -27,8 +27,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun_ref(&A::a2)(a, 5) == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.pass.cpp
index 19c4dca9e7a..1ff7a9af929 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref1.pass.cpp
@@ -24,8 +24,10 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     A a;
     assert(std::mem_fun_ref(&A::a2)(a, 5) == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.cxx1z.fail.cpp
index 0717a41b980..02c3213be15 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun_ref_t<char, A> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.pass.cpp
index 0fac15b3d5c..037454ed219 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_ref_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun_ref_t<char, A> F;
     static_assert((std::is_base_of<std::unary_function<A, char>, F>::value), "");
     const F f(&A::a1);
     A a;
     assert(f(a) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.cxx1z.fail.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.cxx1z.fail.cpp
index 25c3ce85f33..ec379d7241b 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.cxx1z.fail.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.cxx1z.fail.cpp
@@ -26,7 +26,9 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun_t<char, A> F;
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.pass.cpp
index 36205d11b23..e14ea14d12a 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/depr.member.pointer.adaptors/mem_fun_t.pass.cpp
@@ -23,11 +23,13 @@ struct A
     double a4(unsigned i) const {return i-1;}
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::mem_fun_t<char, A> F;
     static_assert((std::is_base_of<std::unary_function<A*, char>, F>::value), "");
     const F f(&A::a1);
     A a;
     assert(f(&a) == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/nothing_to_do.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.adaptors/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.adaptors/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.base/binary_function.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.base/binary_function.pass.cpp
index affa796364a..dbe6d1eb9ef 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.base/binary_function.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.base/binary_function.pass.cpp
@@ -21,9 +21,11 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::binary_function<int, unsigned, char>::first_argument_type, int>::value), "");
     static_assert((std::is_same<std::binary_function<int, unsigned, char>::second_argument_type, unsigned>::value), "");
     static_assert((std::is_same<std::binary_function<int, unsigned, char>::result_type, char>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/depr.base/unary_function.pass.cpp b/libcxx/test/std/depr/depr.function.objects/depr.base/unary_function.pass.cpp
index c0be3d8a5e8..0aaf3fc136c 100644
--- a/libcxx/test/std/depr/depr.function.objects/depr.base/unary_function.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/depr.base/unary_function.pass.cpp
@@ -20,8 +20,10 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::unary_function<unsigned, char>::argument_type, unsigned>::value), "");
     static_assert((std::is_same<std::unary_function<unsigned, char>::result_type, char>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.function.objects/nothing_to_do.pass.cpp b/libcxx/test/std/depr/depr.function.objects/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/depr/depr.function.objects/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/depr/depr.function.objects/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp b/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp
index 08062059907..37b23fc5e8c 100644
--- a/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp
@@ -20,10 +20,12 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     std::strstream::io_state b = std::strstream::eofbit;
     assert(b == std::ios::eofbit);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp b/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp
index b8088f651aa..57a88c95767 100644
--- a/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp
@@ -20,10 +20,12 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     std::strstream::open_mode b = std::strstream::app;
     assert(b == std::ios::app);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp b/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp
index 6c808cb7115..5b48073bd2f 100644
--- a/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp
@@ -20,10 +20,12 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     std::strstream::seek_dir b = std::strstream::cur;
     assert(b == std::ios::cur);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/streamoff.pass.cpp b/libcxx/test/std/depr/depr.ios.members/streamoff.pass.cpp
index 66200175c0b..8abced55ee4 100644
--- a/libcxx/test/std/depr/depr.ios.members/streamoff.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/streamoff.pass.cpp
@@ -20,10 +20,12 @@
 #include <ios>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     static_assert((std::is_integral<std::ios_base::streamoff>::value), "");
     static_assert((std::is_signed<std::ios_base::streamoff>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/streampos.pass.cpp b/libcxx/test/std/depr/depr.ios.members/streampos.pass.cpp
index 7af7c97e25e..7e95727033a 100644
--- a/libcxx/test/std/depr/depr.ios.members/streampos.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/streampos.pass.cpp
@@ -20,9 +20,11 @@
 #include <ios>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     static_assert((std::is_same<std::ios_base::streampos, std::streampos>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.depr_in_cxx11.fail.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.depr_in_cxx11.fail.cpp
index b06816a225e..e00cfe7c328 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.depr_in_cxx11.fail.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.depr_in_cxx11.fail.cpp
@@ -24,7 +24,9 @@
 #include "../test_func.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::bind1st(test_func(1), 5); // expected-error{{'bind1st<test_func, int>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.pass.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.pass.cpp
index e9fc7b39c01..5d89f369f98 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.pass.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.1st/bind1st.pass.cpp
@@ -18,7 +18,9 @@
 
 #include "../test_func.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::bind1st(test_func(1), 5)(10.) == -5.);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.depr_in_cxx11.fail.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.depr_in_cxx11.fail.cpp
index eca83a007b6..d31189b0b98 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.depr_in_cxx11.fail.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.depr_in_cxx11.fail.cpp
@@ -24,7 +24,9 @@
 #include "../test_func.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::bind2nd(test_func(1), 5); // expected-error{{'bind2nd<test_func, int>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.pass.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.pass.cpp
index a7f19fe9813..243ffd1165d 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.pass.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.bind.2nd/bind2nd.pass.cpp
@@ -18,7 +18,9 @@
 
 #include "../test_func.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::bind2nd(test_func(1), 5)(10) == 5.);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.depr_in_cxx11.fail.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.depr_in_cxx11.fail.cpp
index 3ee4154b925..92d93b01f9e 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.depr_in_cxx11.fail.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.depr_in_cxx11.fail.cpp
@@ -24,7 +24,9 @@
 #include "../test_func.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::binder1st<test_func> B1ST; // expected-error{{'binder1st<test_func>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.pass.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.pass.cpp
index 18d4df48d58..66df2614efd 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.pass.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.1st/binder1st.pass.cpp
@@ -51,8 +51,10 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     t.do_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.depr_in_cxx11.fail.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.depr_in_cxx11.fail.cpp
index adecc53bd2a..f2dd190726e 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.depr_in_cxx11.fail.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.depr_in_cxx11.fail.cpp
@@ -24,7 +24,9 @@
 #include "../test_func.h"
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::binder2nd<test_func> B2ND; // expected-error{{'binder2nd<test_func>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.pass.cpp b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.pass.cpp
index 3671d82448f..f8cb7d46726 100644
--- a/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.pass.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/depr.lib.binder.2nd/binder2nd.pass.cpp
@@ -51,8 +51,10 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     t.do_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.lib.binders/nothing_to_do.pass.cpp b/libcxx/test/std/depr/depr.lib.binders/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/depr/depr.lib.binders/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/depr/depr.lib.binders/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp
index 9cce2a3d81b..90288578f15 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     {
         const char buf[] = "123 4.5 dog";
@@ -40,4 +40,6 @@ int main()
         assert(buf[9] == 'o');
         assert(buf[10] == 'g');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp
index 6cf4b621b38..867225bf851 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     {
         const char buf[] = "123 4.5 dog";
@@ -40,4 +40,6 @@ int main()
         assert(buf[5] == '.');
         assert(buf[6] == '5');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp
index b73bf32c9cd..106aaa7687a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "123 4.5 dog";
@@ -40,4 +40,6 @@ int main()
         assert(buf[9] == 'g');
         assert(buf[10] == 'g');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp
index 91421203146..79a0bfeec2f 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "123 4.5 dog";
@@ -40,4 +40,6 @@ int main()
         assert(buf[5] == '5');
         assert(buf[6] == '5');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp
index 66de73a570a..68b2ee8c40b 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const char buf[] = "123 4.5 dog";
@@ -23,4 +23,6 @@ int main()
         std::strstreambuf* sb = in.rdbuf();
         assert(sb->sgetc() == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp
index f4b91c97a74..bae10783837 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp
@@ -15,11 +15,13 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const char buf[] = "123 4.5 dog";
         std::istrstream in(buf);
         assert(in.str() == std::string("123 4.5 dog"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp
index 94c2a488578..80f5af082d3 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp
@@ -16,7 +16,9 @@
 #include <strstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::istream, std::istrstream>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp
index edece7db0a6..81c84fe3217 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "123 4.5 dog";
@@ -38,4 +38,6 @@ int main()
         out << i << ' ' << d << ' ' << s << std::ends;
         assert(out.str() == std::string("123 4.5 dog321 5.5 cat"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp
index 96417da1163..5f9e9e6a88e 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     std::ostrstream out;
     int i = 123;
@@ -25,4 +25,6 @@ int main()
     out << i << ' ' << d << ' ' << s << std::ends;
     assert(out.str() == std::string("123 4.5 dog"));
     out.freeze(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp
index 817597168a8..4b3412edc88 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostrstream out;
@@ -30,4 +30,6 @@ int main()
         assert(out.str() == std::string("a"));
         out.freeze(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp
index a592848ed00..73a4bb81e25 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostrstream out;
@@ -23,4 +23,6 @@ int main()
         out << 123 << ' ' << 4.5 << ' ' << "dog";
         assert(out.pcount() == 11);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp
index 547dde0644b..ff58af45b20 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "123 4.5 dog";
@@ -24,4 +24,6 @@ int main()
         assert(sb->sputc('a') == 'a');
         assert(buf == std::string("a23 4.5 dog"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp
index c9f3e8dc005..60ec02f341d 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostrstream out;
@@ -23,4 +23,6 @@ int main()
         assert(out.str() == std::string("123 4.5 dog"));
         out.freeze(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp
index b394f8326ad..5fde8503723 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp
@@ -16,7 +16,9 @@
 #include <strstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::ostream, std::ostrstream>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp
index 0a542964670..2387b1eebbe 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "123 4.5 dog";
@@ -56,4 +56,6 @@ int main()
         inout << i << ' ' << d << ' ' << s;
         assert(inout.str() == std::string("123 4.5 dog321 5.5 cat"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp
index ff68a3d1d8b..0e278490ab7 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp
@@ -17,7 +17,7 @@
 #include <cstring>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     std::strstream inout;
     int i = 123;
@@ -33,4 +33,6 @@ int main()
     assert(d == 4.5);
     assert(std::strcmp(s.c_str(), "dog") == 0);
     inout.freeze(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp
index f02e7132416..b4eb17397a6 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "123 4.5 dog";
@@ -24,4 +24,6 @@ int main()
         assert(sb->sputc('a') == 'a');
         assert(buf == std::string("a23 4.5 dog"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp
index 8fd137ea67e..dab7c04a6bb 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstream out;
@@ -30,4 +30,6 @@ int main()
         assert(out.str() == std::string("a"));
         out.freeze(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp
index 56624f2b26d..3a7641b23ea 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstream out;
@@ -23,4 +23,6 @@ int main()
         out << 123 << ' ' << 4.5 << ' ' << "dog";
         assert(out.pcount() == 11);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp
index e780e843fbb..f3482c756d0 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstream out;
@@ -23,4 +23,6 @@ int main()
         assert(out.str() == std::string("123 4.5 dog"));
         out.freeze(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp
index 81979d0af50..7944b789996 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp
@@ -21,11 +21,13 @@
 #include <strstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::iostream, std::strstream>::value), "");
     static_assert((std::is_same<std::strstream::char_type, char>::value), "");
     static_assert((std::is_same<std::strstream::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::strstream::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::strstream::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp
index e9003c9e63f..08cb61914a6 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const char buf[] = "abcd";
@@ -36,4 +36,6 @@ int main()
         assert(sb.snextc() == 'd');
         assert(sb.snextc() == EOF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp
index c5acd63a097..19eb15f948c 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstring>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "abcd";
@@ -93,4 +93,6 @@ int main()
         assert(sb.snextc() == 'j');
         assert(sb.snextc() == EOF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp
index d38b8d3c810..8cba11faca8 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const signed char buf[] = "abcd";
@@ -36,4 +36,6 @@ int main()
         assert(sb.snextc() == 'd');
         assert(sb.snextc() == EOF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp
index 03dc3056eca..9546b74dbd5 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         unsigned char buf[] = "abcd";
@@ -36,4 +36,6 @@ int main()
         assert(sb.snextc() == 'd');
         assert(sb.snextc() == EOF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp
index 997e6707c2f..d7587c0055e 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp
@@ -38,7 +38,7 @@ struct test
         {return std::strstreambuf::overflow(c);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test s(my_alloc, my_free);
@@ -47,4 +47,6 @@ int main()
         assert(called == 1);
     }
     assert(called == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp
index 49da5b2626d..2764efd0efd 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstreambuf s;
@@ -27,4 +27,6 @@ int main()
         assert(s.str() == nullptr);
         assert(s.pcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp
index 5d419f7a410..fdd46164bbb 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstring>
 
-int main()
+int main(int, char**)
 {
     {
         signed char buf[] = "abcd";
@@ -93,4 +93,6 @@ int main()
         assert(sb.snextc() == 'j');
         assert(sb.snextc() == EOF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp
index 6a7467dece3..80aafd4481a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstring>
 
-int main()
+int main(int, char**)
 {
     {
         unsigned char buf[] = "abcd";
@@ -93,4 +93,6 @@ int main()
         assert(sb.snextc() == 'j');
         assert(sb.snextc() == EOF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp
index d798eb308b1..4cbb7b80aa7 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstreambuf sb;
@@ -24,4 +24,6 @@ int main()
         sb.freeze(false);
         assert(sb.sputc('a') == 'a');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp
index 7d98f8cfd3d..b47a34ed8f7 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp
@@ -20,7 +20,7 @@
 #include <string>
 #include <strstream>
 
-int main() {
+int main(int, char**) {
   std::ostrstream oss;
   std::string s;
 
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp
index 901dc4a9c5c..1d2f34d924b 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstreambuf sb;
@@ -28,4 +28,6 @@ int main()
         assert(sb.pcount() == 2);
         sb.freeze(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp
index 933b6306e24..04ecb94cbd6 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::strstreambuf sb;
@@ -24,4 +24,6 @@ int main()
         assert(sb.str() == std::string("a"));
         sb.freeze(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp
index 0e5f6a7e6e4..19cb7abf12f 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[12] = "abc";
@@ -43,4 +43,6 @@ int main()
         assert(sb.sputc('1') == '1');
         assert(sb.str() == std::string("12345678901"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp
index 8364ab7ff94..59fdb640d53 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp
@@ -27,7 +27,7 @@ struct test
     virtual int_type pbackfail(int_type c = EOF) {return base::pbackfail(c);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const char buf[] = "123";
@@ -58,4 +58,6 @@ int main()
         assert(sb.pbackfail(EOF) == EOF);
         assert(sb.str() == std::string("133"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp
index 9b5ba9ada70..8e1f22eeb11 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp
@@ -16,7 +16,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "0123456789";
@@ -53,4 +53,6 @@ int main()
         assert(sb.sputc('c') == 'c');
         assert(sb.str() == std::string("012a456c89"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp
index f888a4d88cb..9d13dc4aa82 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp
@@ -16,7 +16,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "0123456789";
@@ -35,4 +35,6 @@ int main()
         assert(sb.sputc('a') == 'a');
         assert(sb.str() == std::string("012a456789"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp
index 85c308ad57c..c78004e2119 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp
@@ -15,7 +15,7 @@
 #include <strstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         char buf[] = "0123456789";
@@ -23,4 +23,6 @@ int main()
         assert(sb.pubsetbuf(0, 0) == &sb);
         assert(sb.str() == std::string("0123456789"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp
index a28d943d9b9..e8da2957c6a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp
@@ -27,7 +27,7 @@ struct test
     base::int_type underflow() {return base::underflow();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         char buf[10] = "123";
@@ -47,4 +47,6 @@ int main()
         assert(sb.underflow() == '4');
         assert(sb.underflow() == '4');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp
index 755916f653c..398605af98a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp
@@ -14,7 +14,9 @@
 #include <strstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::streambuf, std::strstreambuf>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/exception.unexpected/nothing_to_do.pass.cpp b/libcxx/test/std/depr/exception.unexpected/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/depr/exception.unexpected/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/depr/exception.unexpected/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/exception.unexpected/set.unexpected/get_unexpected.pass.cpp b/libcxx/test/std/depr/exception.unexpected/set.unexpected/get_unexpected.pass.cpp
index 0974b2ee95d..7b11c3037f0 100644
--- a/libcxx/test/std/depr/exception.unexpected/set.unexpected/get_unexpected.pass.cpp
+++ b/libcxx/test/std/depr/exception.unexpected/set.unexpected/get_unexpected.pass.cpp
@@ -22,7 +22,7 @@ void f3()
     std::exit(0);
 }
 
-int main()
+int main(int, char**)
 {
 
     std::unexpected_handler old = std::get_unexpected();
@@ -37,4 +37,6 @@ int main()
     std::set_terminate(f3);
     (*old)();
     assert(0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/exception.unexpected/set.unexpected/set_unexpected.pass.cpp b/libcxx/test/std/depr/exception.unexpected/set.unexpected/set_unexpected.pass.cpp
index f46d1d4eec0..38ae81ec9b0 100644
--- a/libcxx/test/std/depr/exception.unexpected/set.unexpected/set_unexpected.pass.cpp
+++ b/libcxx/test/std/depr/exception.unexpected/set.unexpected/set_unexpected.pass.cpp
@@ -22,7 +22,7 @@ void f3()
     std::exit(0);
 }
 
-int main()
+int main(int, char**)
 {
     std::unexpected_handler old = std::set_unexpected(f1);
     // verify there is a previous unexpected handler
@@ -33,4 +33,6 @@ int main()
     std::set_terminate(f3);
     (*old)();
     assert(0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/exception.unexpected/unexpected.handler/unexpected_handler.pass.cpp b/libcxx/test/std/depr/exception.unexpected/unexpected.handler/unexpected_handler.pass.cpp
index 549f8e0a5ac..e4d4869d77a 100644
--- a/libcxx/test/std/depr/exception.unexpected/unexpected.handler/unexpected_handler.pass.cpp
+++ b/libcxx/test/std/depr/exception.unexpected/unexpected.handler/unexpected_handler.pass.cpp
@@ -14,8 +14,10 @@
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     std::unexpected_handler p = f;
     ((void)p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/exception.unexpected/unexpected/unexpected.pass.cpp b/libcxx/test/std/depr/exception.unexpected/unexpected/unexpected.pass.cpp
index 883aa923757..2562b788487 100644
--- a/libcxx/test/std/depr/exception.unexpected/unexpected/unexpected.pass.cpp
+++ b/libcxx/test/std/depr/exception.unexpected/unexpected/unexpected.pass.cpp
@@ -19,9 +19,11 @@ void f1()
     std::exit(0);
 }
 
-int main()
+int main(int, char**)
 {
     std::set_unexpected(f1);
     std::unexpected();
     assert(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/depr/nothing_to_do.pass.cpp b/libcxx/test/std/depr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/depr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/depr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/assertions/cassert.pass.cpp b/libcxx/test/std/diagnostics/assertions/cassert.pass.cpp
index fe54e1852df..a18a4d0df03 100644
--- a/libcxx/test/std/diagnostics/assertions/cassert.pass.cpp
+++ b/libcxx/test/std/diagnostics/assertions/cassert.pass.cpp
@@ -14,6 +14,8 @@
 #error assert not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/diagnostics.general/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/diagnostics.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/diagnostics.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/diagnostics.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/errno/cerrno.pass.cpp b/libcxx/test/std/diagnostics/errno/cerrno.pass.cpp
index 100e5b30b0d..452f99e337a 100644
--- a/libcxx/test/std/diagnostics/errno/cerrno.pass.cpp
+++ b/libcxx/test/std/diagnostics/errno/cerrno.pass.cpp
@@ -339,6 +339,8 @@
 #error errno not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/domain.error/domain_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/domain.error/domain_error.pass.cpp
index 14ded723f16..31a320d113a 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/domain.error/domain_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/domain.error/domain_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::logic_error, std::domain_error>::value),
                  "std::is_base_of<std::logic_error, std::domain_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/invalid.argument/invalid_argument.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/invalid.argument/invalid_argument.pass.cpp
index bcdfe477b35..00d9a9296df 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/invalid.argument/invalid_argument.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/invalid.argument/invalid_argument.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::logic_error, std::invalid_argument>::value),
                  "std::is_base_of<std::logic_error, std::invalid_argument>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/length.error/length_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/length.error/length_error.pass.cpp
index 754f7906152..1e8f1e46c8e 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/length.error/length_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/length.error/length_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::logic_error, std::length_error>::value),
                  "std::is_base_of<std::logic_error, std::length_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/logic.error/logic_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/logic.error/logic_error.pass.cpp
index 279ac7345b7..e30b3b9f8ee 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/logic.error/logic_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/logic.error/logic_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::logic_error>::value),
                  "std::is_base_of<std::exception, std::logic_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/out.of.range/out_of_range.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/out.of.range/out_of_range.pass.cpp
index 8f5a8f2f806..01a5b46b4a4 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/out.of.range/out_of_range.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/out.of.range/out_of_range.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::logic_error, std::out_of_range>::value),
                  "std::is_base_of<std::logic_error, std::out_of_range>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/overflow.error/overflow_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/overflow.error/overflow_error.pass.cpp
index 0e576290d8e..a9e7fb99422 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/overflow.error/overflow_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/overflow.error/overflow_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::runtime_error, std::overflow_error>::value),
                  "std::is_base_of<std::runtime_error, std::overflow_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/range.error/range_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/range.error/range_error.pass.cpp
index 211c53d12e2..92d1151ff6c 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/range.error/range_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/range.error/range_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::runtime_error, std::range_error>::value),
                  "std::is_base_of<std::runtime_error, std::range_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/runtime.error/runtime_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/runtime.error/runtime_error.pass.cpp
index dae3371cd99..c4b8eea74c8 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/runtime.error/runtime_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/runtime.error/runtime_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::runtime_error>::value),
                  "std::is_base_of<std::exception, std::runtime_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/std.exceptions/underflow.error/underflow_error.pass.cpp b/libcxx/test/std/diagnostics/std.exceptions/underflow.error/underflow_error.pass.cpp
index f2588576a6e..88a3f46fbdc 100644
--- a/libcxx/test/std/diagnostics/std.exceptions/underflow.error/underflow_error.pass.cpp
+++ b/libcxx/test/std/diagnostics/std.exceptions/underflow.error/underflow_error.pass.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::runtime_error, std::underflow_error>::value),
                  "std::is_base_of<std::runtime_error, std::underflow_error>::value");
@@ -38,4 +38,6 @@ int main()
     e2 = e;
     assert(e2.what() == msg);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/errc.pass.cpp b/libcxx/test/std/diagnostics/syserr/errc.pass.cpp
index 0738264afdb..201878d2dd5 100644
--- a/libcxx/test/std/diagnostics/syserr/errc.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/errc.pass.cpp
@@ -12,7 +12,7 @@
 
 #include <system_error>
 
-int main()
+int main(int, char**)
 {
     static_assert(static_cast<int>(std::errc::address_family_not_supported) == EAFNOSUPPORT, "");
     static_assert(static_cast<int>(std::errc::address_in_use) == EADDRINUSE, "");
@@ -100,4 +100,6 @@ int main()
     static_assert(static_cast<int>(std::errc::too_many_symbolic_link_levels) == ELOOP, "");
     static_assert(static_cast<int>(std::errc::value_too_large) == EOVERFLOW, "");
     static_assert(static_cast<int>(std::errc::wrong_protocol_type) == EPROTOTYPE, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/is_error_code_enum.pass.cpp b/libcxx/test/std/diagnostics/syserr/is_error_code_enum.pass.cpp
index 2b1416e15d6..2a44b5ee352 100644
--- a/libcxx/test/std/diagnostics/syserr/is_error_code_enum.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/is_error_code_enum.pass.cpp
@@ -39,7 +39,7 @@ namespace std
 }
 
 
-int main()
+int main(int, char**)
 {
     test<false, void>();
     test<false, int>();
@@ -47,4 +47,6 @@ int main()
     test<false, std::string>();
 
     test<true, A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/is_error_condition_enum.pass.cpp b/libcxx/test/std/diagnostics/syserr/is_error_condition_enum.pass.cpp
index 8398c70febb..df89fc334b2 100644
--- a/libcxx/test/std/diagnostics/syserr/is_error_condition_enum.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/is_error_condition_enum.pass.cpp
@@ -39,7 +39,7 @@ namespace std
 }
 
 
-int main()
+int main(int, char**)
 {
     test<false, void>();
     test<false, int>();
@@ -47,4 +47,6 @@ int main()
     test<false, std::string>();
 
     test<true, A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.compare/eq_error_code_error_code.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.compare/eq_error_code_error_code.pass.cpp
index 425406ade46..0e2dbe552bd 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.compare/eq_error_code_error_code.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.compare/eq_error_code_error_code.pass.cpp
@@ -20,7 +20,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::error_code e_code1(5, std::generic_category());
     std::error_code e_code2(5, std::system_category());
@@ -102,4 +102,6 @@ int main()
     assert(e_condition4 != e_condition2);
     assert(e_condition4 != e_condition3);
     assert(e_condition4 == e_condition4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.derived/message.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.derived/message.pass.cpp
index 8aa7fedf6f8..ed580198efc 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.derived/message.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.derived/message.pass.cpp
@@ -18,7 +18,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::generic_category();
     const std::error_category& e_cat2 = std::system_category();
@@ -30,4 +30,6 @@ int main()
     assert(!m3.empty());
     assert(m1 == m2);
     assert(m1 != m3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/default_ctor.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/default_ctor.pass.cpp
index 8e5bda76297..185f96e26eb 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/default_ctor.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/default_ctor.pass.cpp
@@ -27,8 +27,10 @@ public:
     virtual std::string message(int) const {return std::string();}
 };
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_nothrow_default_constructible<test1>::value,
                                  "error_category() must exist and be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/eq.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/eq.pass.cpp
index abe0c36873f..ce09481e324 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/eq.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/eq.pass.cpp
@@ -15,11 +15,13 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::generic_category();
     const std::error_category& e_cat2 = std::generic_category();
     const std::error_category& e_cat3 = std::system_category();
     assert(e_cat1 == e_cat2);
     assert(!(e_cat1 == e_cat3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/lt.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/lt.pass.cpp
index 9b9a1acc0f2..db6b3b90814 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/lt.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/lt.pass.cpp
@@ -15,11 +15,13 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::generic_category();
     const std::error_category& e_cat2 = std::generic_category();
     const std::error_category& e_cat3 = std::system_category();
     assert(!(e_cat1 < e_cat2) && !(e_cat2 < e_cat1));
     assert((e_cat1 < e_cat3) || (e_cat3 < e_cat1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/neq.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/neq.pass.cpp
index 615c9a0bec6..2826018d3d5 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/neq.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.nonvirtuals/neq.pass.cpp
@@ -15,11 +15,13 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::generic_category();
     const std::error_category& e_cat2 = std::generic_category();
     const std::error_category& e_cat3 = std::system_category();
     assert(!(e_cat1 != e_cat2));
     assert(e_cat1 != e_cat3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp
index 73967e90f42..f04427381cb 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp
@@ -35,7 +35,7 @@ void test_message_for_bad_value() {
     assert(errno == E2BIG);
 }
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::generic_category();
     std::string m1 = e_cat1.name();
@@ -43,4 +43,6 @@ int main()
     {
         test_message_for_bad_value();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp
index 78d3a3ef00c..8374c8766b2 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp
@@ -35,7 +35,7 @@ void test_message_for_bad_value() {
     assert(errno == E2BIG);
 }
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::system_category();
     std::error_condition e_cond = e_cat1.default_error_condition(5);
@@ -47,4 +47,6 @@ int main()
     {
         test_message_for_bad_value();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.overview/error_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.overview/error_category.pass.cpp
index b75b6b92437..112c3944885 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.overview/error_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.overview/error_category.pass.cpp
@@ -12,8 +12,10 @@
 
 #include <system_error>
 
-int main()
+int main(int, char**)
 {
     std::error_category* p = 0;
     ((void)p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/default_error_condition.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/default_error_condition.pass.cpp
index 870822cbcbe..07daf6f4912 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/default_error_condition.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/default_error_condition.pass.cpp
@@ -15,10 +15,12 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat = std::generic_category();
     std::error_condition e_cond = e_cat.default_error_condition(static_cast<int>(std::errc::not_a_directory));
     assert(e_cond.category() == e_cat);
     assert(e_cond.value() == static_cast<int>(std::errc::not_a_directory));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_error_code_int.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_error_code_int.pass.cpp
index 89eb8b47523..7682227980e 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_error_code_int.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_error_code_int.pass.cpp
@@ -15,9 +15,11 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat = std::generic_category();
     assert(e_cat.equivalent(std::error_code(5, e_cat), 5));
     assert(!e_cat.equivalent(std::error_code(5, e_cat), 6));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_int_error_condition.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_int_error_condition.pass.cpp
index 76cc198382b..7e627d4097a 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_int_error_condition.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.virtuals/equivalent_int_error_condition.pass.cpp
@@ -15,10 +15,12 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat = std::generic_category();
     std::error_condition e_cond = e_cat.default_error_condition(5);
     assert(e_cat.equivalent(5, e_cond));
     assert(!e_cat.equivalent(6, e_cond));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/ErrorCodeEnum.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/ErrorCodeEnum.pass.cpp
index 50f48e170bc..bfebd012b8d 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/ErrorCodeEnum.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/ErrorCodeEnum.pass.cpp
@@ -33,11 +33,13 @@ make_error_code(testing x)
     return std::error_code(static_cast<int>(x), std::generic_category());
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec(two);
         assert(ec.value() == 2);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/default.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/default.pass.cpp
index 9d7fbba1dfb..3a7249edeae 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/default.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/default.pass.cpp
@@ -15,9 +15,11 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::error_code ec;
     assert(ec.value() == 0);
     assert(ec.category() == std::system_category());
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/int_error_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/int_error_category.pass.cpp
index 99d8f940768..5a2150fbf7f 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/int_error_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.constructors/int_error_category.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec(6, std::system_category());
@@ -27,4 +27,6 @@ int main()
         assert(ec.value() == 8);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/ErrorCodeEnum.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/ErrorCodeEnum.pass.cpp
index aa99f4b3a89..a98e2294456 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/ErrorCodeEnum.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/ErrorCodeEnum.pass.cpp
@@ -33,7 +33,7 @@ make_error_code(testing x)
     return std::error_code(static_cast<int>(x), std::generic_category());
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec;
@@ -41,4 +41,6 @@ int main()
         assert(ec.value() == 2);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/assign.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/assign.pass.cpp
index 2c06d4b9379..998cfd3545e 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/assign.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/assign.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec;
@@ -29,4 +29,6 @@ int main()
         assert(ec.value() == 8);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/clear.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/clear.pass.cpp
index 523562c8e25..c4b7eca258a 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.modifiers/clear.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec;
@@ -26,4 +26,6 @@ int main()
         assert(ec.value() == 0);
         assert(ec.category() == std::system_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/lt.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/lt.pass.cpp
index 98f46eea650..9dc37fc3425 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/lt.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/lt.pass.cpp
@@ -16,11 +16,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_code ec1(6, std::generic_category());
         const std::error_code ec2(7, std::generic_category());
         assert(ec1 < ec2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/make_error_code.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/make_error_code.pass.cpp
index 7917de06e59..1f4603f7c98 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/make_error_code.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/make_error_code.pass.cpp
@@ -15,11 +15,13 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec = make_error_code(std::errc::operation_canceled);
         assert(ec.value() == static_cast<int>(std::errc::operation_canceled));
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/stream_inserter.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/stream_inserter.pass.cpp
index 0828c1fb8e5..37e1d817dbb 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/stream_inserter.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.nonmembers/stream_inserter.pass.cpp
@@ -18,9 +18,11 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream out;
     out << std::error_code(std::io_errc::stream);
     assert(out.str() == "iostream:1");
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.fail.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.fail.cpp
index 6b9838ca73d..902e108a1c1 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.fail.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.fail.cpp
@@ -22,7 +22,7 @@ bool test_func(void)
     return ec;   // conversion to bool is explicit; should fail.
 }
 
-int main()
+int main(int, char**)
 {
     return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.pass.cpp
index da226788c21..11bea5a344e 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/bool.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_code ec(6, std::generic_category());
@@ -26,4 +26,6 @@ int main()
         const std::error_code ec(0, std::generic_category());
         assert(!static_cast<bool>(ec));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/category.pass.cpp
index a2a9ef717b2..16197d934a0 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/category.pass.cpp
@@ -15,8 +15,10 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_code ec(6, std::generic_category());
     assert(ec.category() == std::generic_category());
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/default_error_condition.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/default_error_condition.pass.cpp
index e7119a3e671..4c92b488e20 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/default_error_condition.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/default_error_condition.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_code ec(6, std::generic_category());
@@ -27,4 +27,6 @@ int main()
         std::error_condition e_cond = ec.default_error_condition();
         assert(e_cond == ec);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/message.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/message.pass.cpp
index 7482914e672..513eeae77d5 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/message.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/message.pass.cpp
@@ -16,8 +16,10 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_code ec(6, std::generic_category());
     assert(ec.message() == std::generic_category().message(6));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/value.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/value.pass.cpp
index 5e15e06300d..f1fcee41469 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/value.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.observers/value.pass.cpp
@@ -15,8 +15,10 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_code ec(6, std::system_category());
     assert(ec.value() == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.overview/types.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.overview/types.pass.cpp
index c5f8650d2f5..b2441ac9746 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.overview/types.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcode/syserr.errcode.overview/types.pass.cpp
@@ -14,10 +14,12 @@
 #include <system_error>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::error_code x;
     TEST_IGNORE_NODISCARD  x.category();   // returns a std::error_category &
     TEST_IGNORE_NODISCARD  x.default_error_condition(); // std::error_condition
     TEST_IGNORE_NODISCARD  x.message();    // returns a std::string
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/ErrorConditionEnum.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/ErrorConditionEnum.pass.cpp
index 34c3af883d5..63e718dda30 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/ErrorConditionEnum.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/ErrorConditionEnum.pass.cpp
@@ -15,11 +15,13 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_condition ec(std::errc::not_a_directory);
         assert(ec.value() == static_cast<int>(std::errc::not_a_directory));
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/default.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/default.pass.cpp
index e303920102e..f39904a12e8 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/default.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/default.pass.cpp
@@ -15,9 +15,11 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::error_condition ec;
     assert(ec.value() == 0);
     assert(ec.category() == std::generic_category());
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/int_error_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/int_error_category.pass.cpp
index 82b0de8b6cf..b30c23f1913 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/int_error_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.constructors/int_error_category.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_condition ec(6, std::system_category());
@@ -27,4 +27,6 @@ int main()
         assert(ec.value() == 8);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/ErrorConditionEnum.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/ErrorConditionEnum.pass.cpp
index 0cefa6e3283..129e30e3fa3 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/ErrorConditionEnum.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/ErrorConditionEnum.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_condition ec;
@@ -23,4 +23,6 @@ int main()
         assert(ec.value() == static_cast<int>(std::errc::not_enough_memory));
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/assign.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/assign.pass.cpp
index 44ff3f67eff..a0e27ee5e77 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/assign.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/assign.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_condition ec;
@@ -29,4 +29,6 @@ int main()
         assert(ec.value() == 8);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/clear.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/clear.pass.cpp
index 9dd5bf3035f..5de51aa954a 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.modifiers/clear.pass.cpp
@@ -15,7 +15,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_condition ec;
@@ -26,4 +26,6 @@ int main()
         assert(ec.value() == 0);
         assert(ec.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/lt.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/lt.pass.cpp
index ce57687518e..f1c24514b60 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/lt.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/lt.pass.cpp
@@ -16,11 +16,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_condition ec1(6, std::generic_category());
         const std::error_condition ec2(7, std::generic_category());
         assert(ec1 < ec2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/make_error_condition.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/make_error_condition.pass.cpp
index 6f64e49bfe7..e9e65db5965 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/make_error_condition.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.nonmembers/make_error_condition.pass.cpp
@@ -15,11 +15,13 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_condition ec1 = std::make_error_condition(std::errc::message_size);
         assert(ec1.value() == static_cast<int>(std::errc::message_size));
         assert(ec1.category() == std::generic_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/bool.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/bool.pass.cpp
index 8684393dfd1..bccdf5fb0ac 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/bool.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/bool.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_condition ec(6, std::generic_category());
@@ -26,4 +26,6 @@ int main()
         const std::error_condition ec(0, std::generic_category());
         assert(!static_cast<bool>(ec));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/category.pass.cpp
index d5bbc94b302..f4710a7226c 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/category.pass.cpp
@@ -15,8 +15,10 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_condition ec(6, std::generic_category());
     assert(ec.category() == std::generic_category());
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/message.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/message.pass.cpp
index c5fc8c60a95..e533e84ee4b 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/message.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/message.pass.cpp
@@ -16,8 +16,10 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_condition ec(6, std::generic_category());
     assert(ec.message() == std::generic_category().message(6));
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/value.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/value.pass.cpp
index 03038e1c830..d78b1787492 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/value.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.observers/value.pass.cpp
@@ -15,8 +15,10 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_condition ec(6, std::system_category());
     assert(ec.value() == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.overview/types.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.overview/types.pass.cpp
index f6376d523e3..85a0155d75d 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.overview/types.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcondition/syserr.errcondition.overview/types.pass.cpp
@@ -14,9 +14,11 @@
 #include <system_error>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::error_condition x = std::errc(0);
     TEST_IGNORE_NODISCARD  x.category();   // returns a std::error_condition &
     TEST_IGNORE_NODISCARD  x.message();    // returns a std::string
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.hash/enabled_hash.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.hash/enabled_hash.pass.cpp
index 6be7b4e9c12..c127e900a1c 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.hash/enabled_hash.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::error_code>();
     test_hash_enabled_for_type<std::error_condition>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.hash/error_code.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.hash/error_code.pass.cpp
index 0158f3ff31d..f8c09775f23 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.hash/error_code.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.hash/error_code.pass.cpp
@@ -36,9 +36,11 @@ test(int i)
     ((void)result); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test(0);
     test(2);
     test(10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.hash/error_condition.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.hash/error_condition.pass.cpp
index d651e6d5c6d..b9b0057b98f 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.hash/error_condition.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.hash/error_condition.pass.cpp
@@ -36,9 +36,11 @@ test(int i)
     ((void)result); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test(0);
     test(2);
     test(10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code.pass.cpp
index 4d59735fe94..3e721c2d2e2 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code.pass.cpp
@@ -18,11 +18,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::system_error se(static_cast<int>(std::errc::not_a_directory),
                          std::generic_category(), "some text");
     assert(se.code() == std::make_error_code(std::errc::not_a_directory));
     std::string what_message(se.what());
     assert(what_message.find("Not a directory") != std::string::npos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_const_char_pointer.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_const_char_pointer.pass.cpp
index c2b229a9df9..d15ff75bf9c 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_const_char_pointer.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_const_char_pointer.pass.cpp
@@ -18,7 +18,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::string what_arg("test message");
     std::system_error se(make_error_code(std::errc::not_a_directory), what_arg.c_str());
@@ -26,4 +26,6 @@ int main()
     std::string what_message(se.what());
     assert(what_message.find(what_arg) != std::string::npos);
     assert(what_message.find("Not a directory") != std::string::npos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_string.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_string.pass.cpp
index adca00d1eb6..8e2b078005c 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_string.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_error_code_string.pass.cpp
@@ -18,7 +18,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::string what_arg("test message");
     std::system_error se(make_error_code(std::errc::not_a_directory), what_arg);
@@ -26,4 +26,6 @@ int main()
     std::string what_message(se.what());
     assert(what_message.find(what_arg) != std::string::npos);
     assert(what_message.find("Not a directory") != std::string::npos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category.pass.cpp
index d77d20cfe3c..b1ac08e666d 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category.pass.cpp
@@ -18,11 +18,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::system_error se(static_cast<int>(std::errc::not_a_directory),
                          std::generic_category());
     assert(se.code() == std::make_error_code(std::errc::not_a_directory));
     std::string what_message(se.what());
     assert(what_message.find("Not a directory") != std::string::npos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_const_char_pointer.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_const_char_pointer.pass.cpp
index 789fed6b62f..a6d24326783 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_const_char_pointer.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_const_char_pointer.pass.cpp
@@ -18,7 +18,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::string what_arg("test message");
     std::system_error se(static_cast<int>(std::errc::not_a_directory),
@@ -27,4 +27,6 @@ int main()
     std::string what_message(se.what());
     assert(what_message.find(what_arg) != std::string::npos);
     assert(what_message.find("Not a directory") != std::string::npos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_string.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_string.pass.cpp
index 29df242f0e2..913c675b9a1 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_string.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.members/ctor_int_error_category_string.pass.cpp
@@ -18,7 +18,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::string what_arg("test message");
     std::system_error se(static_cast<int>(std::errc::not_a_directory),
@@ -27,4 +27,6 @@ int main()
     std::string what_message(se.what());
     assert(what_message.find(what_arg) != std::string::npos);
     assert(what_message.find("Not a directory") != std::string::npos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.overview/nothing_to_do.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.overview/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.overview/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.syserr/syserr.syserr.overview/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/algorithms/alg.search/search.pass.cpp b/libcxx/test/std/experimental/algorithms/alg.search/search.pass.cpp
index 4faa6549ebb..45b1f09729b 100644
--- a/libcxx/test/std/experimental/algorithms/alg.search/search.pass.cpp
+++ b/libcxx/test/std/experimental/algorithms/alg.search/search.pass.cpp
@@ -35,11 +35,13 @@ struct MySearcher {
 };
 
 
-int main() {
+int main(int, char**) {
     typedef int * RI;
     static_assert((std::is_same<RI, decltype(std::experimental::search(RI(), RI(), MySearcher()))>::value), "" );
 
     RI it(nullptr);
     assert(it == std::experimental::search(it, it, MySearcher()));
     assert(searcher_called == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/filesystem/fs.req.macros/feature_macro.pass.cpp b/libcxx/test/std/experimental/filesystem/fs.req.macros/feature_macro.pass.cpp
index 6c216bd20d3..595162d309a 100644
--- a/libcxx/test/std/experimental/filesystem/fs.req.macros/feature_macro.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/fs.req.macros/feature_macro.pass.cpp
@@ -25,4 +25,6 @@
 #endif
 #endif
 
-int main() { }
+int main(int, char**) { 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/filesystem/fs.req.namespace/namespace.pass.cpp b/libcxx/test/std/experimental/filesystem/fs.req.namespace/namespace.pass.cpp
index 5e1920f8935..87086d42958 100644
--- a/libcxx/test/std/experimental/filesystem/fs.req.namespace/namespace.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/fs.req.namespace/namespace.pass.cpp
@@ -15,9 +15,11 @@
 #include <experimental/filesystem>
 #include <type_traits>
 
-int main() {
+int main(int, char**) {
   static_assert(std::is_same<
           std::experimental::filesystem::path,
           std::experimental::filesystem::v1::path
       >::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/default.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/default.pass.cpp
index 21780ab8076..35c5e50bbe7 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/default.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/default.pass.cpp
@@ -121,7 +121,9 @@ test2()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pass.cpp
index c1546706ec3..245b3ddfc7f 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pass.cpp
@@ -117,7 +117,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pred.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pred.pass.cpp
index 0614cb98731..ad90954758e 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pred.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/hash.pred.pass.cpp
@@ -135,7 +135,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/pred.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/pred.pass.cpp
index 12ab20cdd44..a361b90b852 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/pred.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore/pred.pass.cpp
@@ -126,7 +126,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/default.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/default.pass.cpp
index 0cd6174afce..95426f81c88 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/default.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/default.pass.cpp
@@ -121,7 +121,9 @@ test2()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pass.cpp
index 0fe8420a518..151a0f46b41 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pass.cpp
@@ -116,7 +116,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pred.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pred.pass.cpp
index 916660c1eb0..bcdaa87c4a4 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pred.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/hash.pred.pass.cpp
@@ -129,7 +129,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/pred.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/pred.pass.cpp
index 3cdac5ffd37..06a93c5d7b7 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/pred.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.boyer_moore_horspool/pred.pass.cpp
@@ -123,7 +123,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pass.cpp
index 524bba17d40..b3f6c66387f 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pass.cpp
@@ -82,7 +82,7 @@ test()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -92,4 +92,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pred.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pred.pass.cpp
index a4d0b0730a1..f1573a2e067 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pred.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/default.pred.pass.cpp
@@ -89,7 +89,7 @@ test()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -99,4 +99,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pass.cpp
index 3bf33c808b6..5187569ecf3 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pass.cpp
@@ -67,7 +67,7 @@ test()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -77,4 +77,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pred.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pred.pass.cpp
index a827f3d2a4b..a6996437ec1 100644
--- a/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pred.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/func.searchers.default/func.searchers.default.creation/make_default_searcher.pred.pass.cpp
@@ -74,7 +74,7 @@ test()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -84,4 +84,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/func.searchers/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/func/func.searchers/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/experimental/func/func.searchers/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/func/func.searchers/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/header.functional.synop/includes.pass.cpp b/libcxx/test/std/experimental/func/header.functional.synop/includes.pass.cpp
index 805d8c8fdc9..4b913c2d780 100644
--- a/libcxx/test/std/experimental/func/header.functional.synop/includes.pass.cpp
+++ b/libcxx/test/std/experimental/func/header.functional.synop/includes.pass.cpp
@@ -14,7 +14,9 @@
 
 #include <experimental/functional>
 
-int main()
+int main(int, char**)
 {
   std::function<int(int)> x;
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/func/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/func/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/experimental/func/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/func/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/iterator/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/iterator/nothing_to_do.pass.cpp
index 85149549f17..782c1a03ee5 100644
--- a/libcxx/test/std/experimental/iterator/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/nothing_to_do.pass.cpp
@@ -8,4 +8,6 @@
 
 #include <experimental/iterator>
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.cons/ostream_joiner.cons.pass.cpp b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.cons/ostream_joiner.cons.pass.cpp
index 869af67bc62..4e3994f9560 100644
--- a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.cons/ostream_joiner.cons.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.cons/ostream_joiner.cons.pass.cpp
@@ -24,7 +24,7 @@
 
 namespace exp = std::experimental;
 
-int main () {
+int main(int, char**) {
     const char eight = '8';
     const std::string nine = "9";
     const std::wstring ten = L"10";
@@ -54,4 +54,6 @@ int main () {
     { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, ten); }
     { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, eleven); }
 
-    }
+    
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp
index b8e98b9048f..a2dab9afbb6 100644
--- a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp
@@ -39,7 +39,7 @@ void test (Delim &&d, Iter first, Iter last, const CharT *expected ) {
     assert(sstream.str() == expected);
     }
 
-int main () {
+int main(int, char**) {
     const char chars[] = "0123456789";
     const int  ints [] = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
 
@@ -49,4 +49,6 @@ int main () {
     test('x', ints,  ints+10,  "10x11x12x13x14x15x16x17x18x19");
     test("Z", chars, chars+10, "0Z1Z2Z3Z4Z5Z6Z7Z8Z9");
     test("z", ints,  ints+10,  "10z11z12z13z14z15z16z17z18z19");
-    }
+    
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp
index 674f2863d6a..c1bf74afcd5 100644
--- a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp
@@ -67,7 +67,7 @@ void test (Delim &&d, Iter first, Iter last, const CharT *expected ) {
     assert(sstream.str() == expected);
     }
 
-int main () {
+int main(int, char**) {
 {
     const char chars[] = "0123456789";
     const int  ints [] = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
@@ -116,4 +116,6 @@ int main () {
     test(mutating_delimiter(), chars, chars+10, L"0 1!2\"3#4$5%6&7'8(9");
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.postincrement.pass.cpp b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.postincrement.pass.cpp
index 69d2258b13e..095020eb63c 100644
--- a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.postincrement.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.postincrement.pass.cpp
@@ -31,7 +31,7 @@ void test ( exp::ostream_joiner<Delim, CharT, Traits> &oj ) {
     assert( &ret == &oj );
     }
 
-int main () {
+int main(int, char**) {
 
     { exp::ostream_joiner<char>         oj(std::cout, '8');                 test(oj); }
     { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9"));    test(oj); }
@@ -42,4 +42,6 @@ int main () {
     { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9"));    test(oj); }
     { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); test(oj); }
     { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11);                  test(oj); }
-    }
+    
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.pretincrement.pass.cpp b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.pretincrement.pass.cpp
index e7210ac721f..2e305c2ff7c 100644
--- a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.pretincrement.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.pretincrement.pass.cpp
@@ -31,7 +31,7 @@ void test ( exp::ostream_joiner<Delim, CharT, Traits> &oj ) {
     assert( &ret == &oj );
     }
 
-int main () {
+int main(int, char**) {
 
     { exp::ostream_joiner<char>         oj(std::cout, '8');                 test(oj); }
     { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9"));    test(oj); }
@@ -42,4 +42,6 @@ int main () {
     { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9"));    test(oj); }
     { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); test(oj); }
     { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11);                  test(oj); }
-    }
+    
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.star.pass.cpp b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.star.pass.cpp
index d9661510bee..74bf9c30911 100644
--- a/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.star.pass.cpp
+++ b/libcxx/test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.star.pass.cpp
@@ -31,7 +31,7 @@ void test ( exp::ostream_joiner<Delim, CharT, Traits> &oj ) {
     assert( &ret == &oj );
     }
 
-int main () {
+int main(int, char**) {
 
     { exp::ostream_joiner<char>         oj(std::cout, '8');                 test(oj); }
     { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9"));    test(oj); }
@@ -42,4 +42,6 @@ int main () {
     { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9"));    test(oj); }
     { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); test(oj); }
     { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11);                  test(oj); }
-    }
+    
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.capacity/operator_bool.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.capacity/operator_bool.pass.cpp
index 99786488114..b3fbd27632e 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.capacity/operator_bool.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.capacity/operator_bool.pass.cpp
@@ -50,8 +50,10 @@ void do_test() {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test<coro::coroutine_handle<>>();
   do_test<coro::coroutine_handle<int>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/equal_comp.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/equal_comp.pass.cpp
index 8b205ab8915..f6290fdfa99 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/equal_comp.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/equal_comp.pass.cpp
@@ -44,7 +44,7 @@ void do_test(uintptr_t LHSVal, uintptr_t RHSVal) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   std::pair<uintptr_t, uintptr_t> const TestCases[] = {
       {0, 0},
@@ -56,4 +56,6 @@ int main()
     do_test<coro::coroutine_handle<>>(TC.first, TC.second);
     do_test<coro::coroutine_handle<int>>(TC.first, TC.second);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/less_comp.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/less_comp.pass.cpp
index 428b2e4b09e..8152b53f988 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/less_comp.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/less_comp.pass.cpp
@@ -53,7 +53,7 @@ void do_test(uintptr_t LHSVal, uintptr_t RHSVal) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   std::pair<uintptr_t, uintptr_t> const TestCases[] = {
       {0, 0},
@@ -65,4 +65,6 @@ int main()
     do_test<coro::coroutine_handle<>>(TC.first, TC.second);
     do_test<coro::coroutine_handle<int>>(TC.first, TC.second);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.completion/done.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.completion/done.pass.cpp
index 39c279fe82d..14ac3976e19 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.completion/done.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.completion/done.pass.cpp
@@ -36,8 +36,10 @@ void do_test(coro::coroutine_handle<Promise> const& H) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test(coro::coroutine_handle<>{});
   do_test(coro::coroutine_handle<int>{});
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/assign.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/assign.pass.cpp
index da14b4b60f9..2af0b717ea6 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/assign.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/assign.pass.cpp
@@ -46,8 +46,10 @@ void do_test() {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test<coro::coroutine_handle<>>();
   do_test<coro::coroutine_handle<int>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/construct.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/construct.pass.cpp
index 84fa9314dab..7832856c1cf 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/construct.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/construct.pass.cpp
@@ -45,8 +45,10 @@ void do_test() {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test<coro::coroutine_handle<>>();
   do_test<coro::coroutine_handle<int>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/address.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/address.pass.cpp
index 6559ad52d7f..3c63dbbeb30 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/address.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/address.pass.cpp
@@ -43,8 +43,10 @@ void do_test() {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test<coro::coroutine_handle<>>();
   do_test<coro::coroutine_handle<int>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.fail.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.fail.cpp
index 9e9490a3ee7..e9dd0678f4f 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.fail.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.fail.cpp
@@ -26,7 +26,7 @@
 
 namespace coro = std::experimental;
 
-int main()
+int main(int, char**)
 {
   {
     using H = coro::coroutine_handle<>;
@@ -42,4 +42,6 @@ int main()
     // expected-error@experimental/coroutine:* 1 {{coroutine_handle<promise_type>::from_address cannot be called with non-void pointers}}
     H::from_address((int*)nullptr); // expected-note {{requested here}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.pass.cpp
index e856ca12ed6..9c4a647e5fc 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.pass.cpp
@@ -38,8 +38,10 @@ void do_test() {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test<coro::coroutine_handle<>>();
   do_test<coro::coroutine_handle<int>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.hash/hash.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.hash/hash.pass.cpp
index 59c20b84930..612380b6de0 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.hash/hash.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.hash/hash.pass.cpp
@@ -47,7 +47,7 @@ void do_test(uintptr_t LHSVal, uintptr_t RHSVal) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   std::pair<uintptr_t, uintptr_t> const TestCases[] = {
       {0, 0},
@@ -59,4 +59,6 @@ int main()
     do_test<coro::coroutine_handle<>>(TC.first, TC.second);
     do_test<coro::coroutine_handle<int>>(TC.first, TC.second);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.noop/noop_coroutine.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.noop/noop_coroutine.pass.cpp
index eabf03ef0c7..27b83ce02e1 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.noop/noop_coroutine.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.noop/noop_coroutine.pass.cpp
@@ -44,7 +44,7 @@ static_assert(std::is_same<decltype(coro::noop_coroutine()), coro::noop_coroutin
 // // 18.11.2.10 noop address
 // constexpr void* address() const noexcept;
 
-int main()
+int main(int, char**)
 {
   auto h = coro::noop_coroutine();
   coro::coroutine_handle<> base = h;
@@ -65,10 +65,12 @@ int main()
   assert(h.address() == base.address());
   assert(h.address() != nullptr);
   assert(coro::coroutine_handle<>::from_address(h.address()) == base);
+
+  return 0;
 }
 
 #else
 
-int main() {}
+int main(int, char**) { return 0; }
 
 #endif //  __has_builtin(__builtin_coro_noop)
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
index 87e182e03dc..0f81fdca85b 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
@@ -75,9 +75,11 @@ void do_test(coro::coroutine_handle<Promise>&& H) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test(coro::coroutine_handle<int>{});
   do_test(coro::coroutine_handle<const int>{});
   do_runtime_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/destroy.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/destroy.pass.cpp
index 693e0518fdd..72ba9fee637 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/destroy.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/destroy.pass.cpp
@@ -53,8 +53,10 @@ void do_test(coro::coroutine_handle<Promise>&& H) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test(coro::coroutine_handle<>{});
   do_test(coro::coroutine_handle<int>{});
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/resume.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/resume.pass.cpp
index 85d84a4351e..a3804ae43a5 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/resume.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/resume.pass.cpp
@@ -72,8 +72,10 @@ void do_test(coro::coroutine_handle<Promise>&& H) {
   }
 }
 
-int main()
+int main(int, char**)
 {
   do_test(coro::coroutine_handle<>{});
   do_test(coro::coroutine_handle<int>{});
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/void_handle.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/void_handle.pass.cpp
index a2214ba108c..8536e23d462 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/void_handle.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.handle/void_handle.pass.cpp
@@ -41,10 +41,12 @@ void check_type() {
   static_assert(std::is_same<P, Expect>::value, "");
 };
 
-int main()
+int main(int, char**)
 {
   check_type<A*, A>();
   check_type<int*, A, int>();
   check_type<B*, B>();
   check_type<void, C>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp
index b06dac41bed..781f264ffd7 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp
@@ -60,7 +60,7 @@ void check_no_type() {
   static_assert(!has_promise_type<Traits>(), "");
 }
 
-int main()
+int main(int, char**)
 {
   {
     check_type<A*, A>();
@@ -73,4 +73,6 @@ int main()
     check_no_type<E>();
     check_no_type<C, int>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_always.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_always.pass.cpp
index 93ac4719667..89f1619df60 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_always.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_always.pass.cpp
@@ -31,7 +31,7 @@ constexpr bool check_suspend_constexpr() {
   return true;
 }
 
-int main()
+int main(int, char**)
 {
   using H = coro::coroutine_handle<>;
   using S = SuspendT;
@@ -69,4 +69,6 @@ int main()
     // suppress unused warnings for the global constexpr test variable
     ((void)constexpr_sa);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_never.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_never.pass.cpp
index 2ff45941796..7986b292649 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_never.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_never.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool check_suspend_constexpr() {
 }
 
 
-int main()
+int main(int, char**)
 {
   using H = coro::coroutine_handle<>;
   using S = SuspendT;
@@ -71,4 +71,6 @@ int main()
     // suppress unused warnings for the global constexpr test variable
     ((void)constexpr_sn);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/await_result.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/await_result.pass.cpp
index a5ec2075612..c540ca9fb35 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/await_result.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/await_result.pass.cpp
@@ -59,10 +59,12 @@ coro_t f(int n) {
 
 coro_t g() { B val = co_await B{}; }
 
-int main() {
+int main(int, char**) {
   last_value = -1;
   f(0);
   assert(last_value == 0);
   f(1);
   assert(last_value == 42);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/bool_await_suspend.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/bool_await_suspend.pass.cpp
index ea30b89771f..fb15ade8bb2 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/bool_await_suspend.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/bool_await_suspend.pass.cpp
@@ -57,7 +57,7 @@ coro_t g() {
   g_resumed = true;
 }
 
-int main() {
+int main(int, char**) {
   assert(!f_started && !f_resumed && !g_started && !g_resumed);
   auto fret = f();
   assert(f_started && !f_resumed);
@@ -65,4 +65,6 @@ int main() {
   assert(f_started && !f_resumed);
   g();
   assert(g_started && g_resumed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/expected.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/expected.pass.cpp
index 4358f670038..a899092d034 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/expected.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/expected.pass.cpp
@@ -75,7 +75,7 @@ expected<int> f2() {
   co_return 200;
 }
 
-int main() {
+int main(int, char**) {
   auto c1 = f1();
   assert(f1_started && f1_resumed);
   assert(c1.value() == 100);
@@ -85,4 +85,6 @@ int main() {
   assert(f2_started && !f2_resumed);
   assert(c2.value() == 0);
   assert(c2.error() == 42);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/fullexpr-dtor.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/fullexpr-dtor.pass.cpp
index 62fe61a3175..87d3c8f9d68 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/fullexpr-dtor.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/fullexpr-dtor.pass.cpp
@@ -108,9 +108,11 @@ coro2 d() {
   assert(dtor_called == 1);
 }
 
-int main() {
+int main(int, char**) {
   a();
   b();
   c();
   d();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/generator.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/generator.pass.cpp
index e885358d2d8..84b4deb9ce4 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/generator.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/generator.pass.cpp
@@ -95,8 +95,10 @@ void test_mini_generator() {
   assert(sum == 10);
 }
 
-int main() {
+int main(int, char**) {
   test_count();
   test_range();
   test_mini_generator();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/go.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/go.pass.cpp
index 18e96b680de..994bd87d6de 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/go.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/go.pass.cpp
@@ -164,7 +164,7 @@ goroutine pusher(channel& left, channel& right)
 const int N = 100;
 channel* c = new channel[N + 1];
 
-int main() {
+int main(int, char**) {
   for (int i = 0; i < N; ++i)
     goroutine::go(pusher(c[i], c[i + 1]));
 
@@ -172,4 +172,6 @@ int main() {
   int result = c[N].sync_pull();
 
   assert(result == 100);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/multishot_func.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/multishot_func.pass.cpp
index 1b7bdd16106..fed97ea2308 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/multishot_func.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/multishot_func.pass.cpp
@@ -80,7 +80,9 @@ int Do(int acc, int n, func<int> f) {
   return acc;
 }
 
-int main() {
+int main(int, char**) {
   int result = Do(1, 10, [](int a, int b) {return a + b;});
   assert(result == 46);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/oneshot_func.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/oneshot_func.pass.cpp
index 567f438daa5..4bab2dd3bf2 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/oneshot_func.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/oneshot_func.pass.cpp
@@ -72,11 +72,13 @@ float fyield(int x) { yielded_values.push_back(x); return static_cast<float>(x +
 void Do1(func<int> f) { yield(f()); }
 void Do2(func<double> f) { yield(static_cast<int>(f())); }
 
-int main() {
+int main(int, char**) {
   Do1([] { return yield(43); });
   assert((yielded_values == std::vector<int>{43, 44}));
 
   yielded_values = {};
   Do2([] { return fyield(44); });
   assert((yielded_values == std::vector<int>{44, 46}));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/language.support/support.coroutines/includes.pass.cpp b/libcxx/test/std/experimental/language.support/support.coroutines/includes.pass.cpp
index 8fc7b4cc80b..440ffa113a1 100644
--- a/libcxx/test/std/experimental/language.support/support.coroutines/includes.pass.cpp
+++ b/libcxx/test/std/experimental/language.support/support.coroutines/includes.pass.cpp
@@ -15,10 +15,11 @@
 
 #include <experimental/coroutine>
 
-int main(){
+int main(int, char**) {
   // std::nothrow is not implicitly defined by the compiler when the include is
   // missing, unlike other parts of <new>. Therefore we use std::nothrow to
   // test for #include <new>
   (void)std::nothrow;
 
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/assign.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/assign.pass.cpp
index 885137e762e..35a98b789ef 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/assign.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/assign.pass.cpp
@@ -20,9 +20,11 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> T;
     static_assert(!std::is_copy_assignable<T>::value, "");
     static_assert(!std::is_move_assignable<T>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/copy.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/copy.pass.cpp
index 1500f641d3f..ce3c9be105d 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/copy.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/copy.pass.cpp
@@ -20,7 +20,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> A1;
     {
@@ -44,4 +44,6 @@ int main()
         assert(a.resource() == a2.resource());
         assert(a2.resource() == (ex::memory_resource*)42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/default.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/default.pass.cpp
index acec1a02def..6a60021e543 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/default.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/default.pass.cpp
@@ -23,7 +23,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     {
         static_assert(
@@ -45,4 +45,6 @@ int main()
         assert(a.resource() == &R1);
         assert(a2.resource() == ex::new_delete_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/memory_resource_convert.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/memory_resource_convert.pass.cpp
index 0e963117d66..77748ea122a 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/memory_resource_convert.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/memory_resource_convert.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     {
         typedef ex::polymorphic_allocator<void> A;
@@ -41,4 +41,6 @@ int main()
         A const a(&R);
         assert(a.resource() == &R);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/other_alloc.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/other_alloc.pass.cpp
index c0a685615ca..21a56f67b5f 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/other_alloc.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.ctor/other_alloc.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> A1;
     typedef ex::polymorphic_allocator<char> A2;
@@ -53,4 +53,6 @@ int main()
         assert(a.resource() == a2.resource());
         assert(a2.resource() == (ex::memory_resource*)42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/equal.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/equal.pass.cpp
index 84672d3b340..6877885a72d 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/equal.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/equal.pass.cpp
@@ -26,7 +26,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> A1;
     typedef ex::polymorphic_allocator<int> A2;
@@ -130,4 +130,6 @@ int main()
         assert(d1.checkIsEqualCalledEq(0));
         assert(d2.checkIsEqualCalledEq(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/not_equal.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/not_equal.pass.cpp
index 7ce6ec1fc5e..39bc3e28ffd 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/not_equal.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.eq/not_equal.pass.cpp
@@ -26,7 +26,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> A1;
     typedef ex::polymorphic_allocator<int> A2;
@@ -101,4 +101,6 @@ int main()
         assert(d1.checkIsEqualCalledEq(0));
         assert(d2.checkIsEqualCalledEq(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/allocate.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/allocate.pass.cpp
index a489e865c67..ce9c82fb4b5 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/allocate.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/allocate.pass.cpp
@@ -80,7 +80,7 @@ void testAllocForSizeThrows() {
 }
 #endif // TEST_HAS_NO_EXCEPTIONS
 
-int main()
+int main(int, char**)
 {
     {
         ex::polymorphic_allocator<int> a;
@@ -108,4 +108,6 @@ int main()
         testAllocForSizeThrows<13>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair.pass.cpp
index 66a072fb2db..739d95126f8 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair.pass.cpp
@@ -34,7 +34,7 @@ struct default_constructible
     int x{0};
 };
 
-int main()
+int main(int, char**)
 {
     // pair<default_constructible, default_constructible> as T()
     {
@@ -49,4 +49,6 @@ int main()
         assert(ptr->second.x == 42);
         std::free(ptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_const_lvalue_pair.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_const_lvalue_pair.pass.cpp
index 16309d6626a..862657a31db 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_const_lvalue_pair.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_const_lvalue_pair.pass.cpp
@@ -118,7 +118,7 @@ void test_pmr_not_uses_allocator(std::pair<TT, UU> const& p)
 template <class Tp>
 struct Print;
 
-int main()
+int main(int, char**)
 {
     using ERT = std::experimental::erased_type;
     using PMR = ex::memory_resource*;
@@ -139,4 +139,6 @@ int main()
         test_pmr_not_uses_allocator<PMR>(p);
         test_pmr_uses_allocator<PMA>(p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_rvalue.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_rvalue.pass.cpp
index 91e96cf3982..479587ed0d9 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_rvalue.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_rvalue.pass.cpp
@@ -114,7 +114,7 @@ void test_pmr_not_uses_allocator(std::pair<TT, UU>&& p)
     }
 }
 
-int main()
+int main(int, char**)
 {
     using ERT = std::experimental::erased_type;
     using PMR = ex::memory_resource*;
@@ -135,4 +135,6 @@ int main()
         test_pmr_not_uses_allocator<PMR>(std::move(p));
         test_pmr_uses_allocator<PMA>(std::move(p));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_values.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_values.pass.cpp
index d6fa37b8480..9f558581a9c 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_values.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_pair_values.pass.cpp
@@ -121,7 +121,7 @@ void test_pmr_not_uses_allocator(TT&& t, UU&& u)
     }
 }
 
-int main()
+int main(int, char**)
 {
     using ERT = std::experimental::erased_type;
     using PMR = ex::memory_resource*;
@@ -140,4 +140,6 @@ int main()
         test_pmr_not_uses_allocator<PMR>(std::move(x), y);
         test_pmr_uses_allocator<PMA>(std::move(x), y);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair.pass.cpp
index f043c301e01..91f31546892 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair.pass.cpp
@@ -111,7 +111,7 @@ void test_pmr_not_uses_allocator(std::tuple<TTypes...> ttuple, std::tuple<UTypes
     }
 }
 
-int main()
+int main(int, char**)
 {
     using ERT = std::experimental::erased_type;
     using PMR = ex::memory_resource*;
@@ -159,4 +159,6 @@ int main()
         test_pmr_uses_allocator<PMA>(           t1, std::move(t2));
         test_pmr_uses_allocator<PMA>(std::move(t2),            t1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair_evil.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair_evil.pass.cpp
index dc19ae170fb..4f30d13c8f4 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair_evil.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_piecewise_pair_evil.pass.cpp
@@ -120,7 +120,7 @@ void test_evil()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_evil<WidgetV0, WidgetV0>();
     test_evil<WidgetV0, WidgetV1>();
@@ -138,4 +138,6 @@ int main()
     test_evil<WidgetV3, WidgetV1>();
     test_evil<WidgetV3, WidgetV2>();
     test_evil<WidgetV3, WidgetV3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_types.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_types.pass.cpp
index adfe683e23f..526988199cc 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_types.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/construct_types.pass.cpp
@@ -187,7 +187,7 @@ void test_non_pmr_uses_alloc(AllocObj const& A, Args&&... args)
     }
 }
 
-int main()
+int main(int, char**)
 {
     using ET = std::experimental::erased_type;
     using PMR = ex::memory_resource*;
@@ -223,4 +223,6 @@ int main()
         test_non_pmr_uses_alloc<STDA>(std_alloc, cvalue, std::move(value));
         test_non_pmr_uses_alloc<TESTA>(test_alloc, cvalue, std::move(value));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/deallocate.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/deallocate.pass.cpp
index 8dadb1773da..022478da75d 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/deallocate.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/deallocate.pass.cpp
@@ -41,7 +41,7 @@ void testForSizeAndAlign() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         ex::polymorphic_allocator<int> a;
@@ -58,4 +58,6 @@ int main()
         testForSizeAndAlign<73, MA>();
         testForSizeAndAlign<13, MA>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/destroy.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/destroy.pass.cpp
index 75c04c53c91..0a1b60dc2fe 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/destroy.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/destroy.pass.cpp
@@ -32,7 +32,7 @@ struct destroyable
     ~destroyable() { --count; }
 };
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<double> A;
     {
@@ -48,4 +48,6 @@ int main()
         assert(count == 0);
         std::free(ptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/resource.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/resource.pass.cpp
index 11d392f5939..b05f2b292ca 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/resource.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/resource.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> A;
     {
@@ -53,4 +53,6 @@ int main()
         assert(a.resource() == mptr);
         assert(a.resource() == ex::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/select_on_container_copy_construction.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/select_on_container_copy_construction.pass.cpp
index 7c7c07d5250..92beab473ab 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/select_on_container_copy_construction.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.mem/select_on_container_copy_construction.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::polymorphic_allocator<void> A;
     {
@@ -49,4 +49,6 @@ int main()
         assert(other.resource() == mptr);
         assert(a.resource() == nullptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.overview/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.overview/nothing_to_do.pass.cpp
index 98c4bdd4f1c..796f3c353ba 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.overview/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/memory.polymorphic.allocator.overview/nothing_to_do.pass.cpp
@@ -6,4 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/nothing_to_do.pass.cpp
index 98c4bdd4f1c..796f3c353ba 100644
--- a/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.polymorphic.allocator.class/nothing_to_do.pass.cpp
@@ -6,4 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_copy.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_copy.pass.cpp
index 09249219f40..4466b2b4e51 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_copy.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_copy.pass.cpp
@@ -21,7 +21,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef CountingAllocator<char> AllocT;
     typedef ex::resource_adaptor<AllocT> R;
@@ -49,4 +49,6 @@ int main()
         assert(P.move_constructed == 0);
         assert(r.get_allocator() == a);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_move.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_move.pass.cpp
index df54ba503aa..b6af8515100 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_move.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/alloc_move.pass.cpp
@@ -21,7 +21,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef CountingAllocator<char> AllocT;
     typedef ex::resource_adaptor<AllocT> R;
@@ -40,4 +40,6 @@ int main()
         assert(P.move_constructed == 1);
         assert(r.get_allocator() == AllocT{P});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/default.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/default.pass.cpp
index 5550e4fa519..53481ab39f2 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/default.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.ctor/default.pass.cpp
@@ -23,7 +23,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     {
         typedef CountingAllocator<char> AllocT; // Not default constructible
@@ -36,4 +36,6 @@ int main()
         static_assert(std::is_default_constructible<R>::value, "");
         R r; ((void)r);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_allocate_and_deallocate.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_allocate_and_deallocate.pass.cpp
index b2dc3aae18c..806fa6e95e1 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_allocate_and_deallocate.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_allocate_and_deallocate.pass.cpp
@@ -106,9 +106,11 @@ void check_alloc_max_size() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     check_allocate_deallocate<CountingAllocator<char>>();
     check_allocate_deallocate<MinAlignedAllocator<char>>();
     check_alloc_max_size();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_is_equal.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_is_equal.pass.cpp
index baa8e17c52f..71c36693c3c 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_is_equal.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.mem/do_is_equal.pass.cpp
@@ -23,7 +23,7 @@
 using std::size_t;
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
 
     typedef CountingAllocator<char> Alloc1;
@@ -79,4 +79,6 @@ int main()
         assert(!m1.is_equal(m2));
         assert(!m2.is_equal(m1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.overview/overview.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.overview/overview.pass.cpp
index a47968e905a..873dfd9391c 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.overview/overview.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.adaptor/memory.resource.adaptor.overview/overview.pass.cpp
@@ -19,7 +19,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     typedef ex::resource_adaptor<std::allocator<void>> R;
     typedef ex::resource_adaptor<std::allocator<long>> R2;
@@ -35,4 +35,6 @@ int main()
         static_assert(std::is_copy_assignable<R>::value, "");
         static_assert(std::is_move_assignable<R>::value, "");
    }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_deque_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_deque_synop.pass.cpp
index 80e3c6e2e5d..2aba4431e63 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_deque_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_deque_synop.pass.cpp
@@ -26,11 +26,13 @@
 
 namespace pmr = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     using StdDeque = std::deque<int, pmr::polymorphic_allocator<int>>;
     using PmrDeque = pmr::deque<int>;
     static_assert(std::is_same<StdDeque, PmrDeque>::value, "");
     PmrDeque d;
     assert(d.get_allocator().resource() == pmr::get_default_resource());
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_forward_list_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_forward_list_synop.pass.cpp
index 5fc71fb9a18..66adb0b511d 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_forward_list_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_forward_list_synop.pass.cpp
@@ -26,11 +26,13 @@
 
 namespace pmr = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     using StdForwardList = std::forward_list<int, pmr::polymorphic_allocator<int>>;
     using PmrForwardList = pmr::forward_list<int>;
     static_assert(std::is_same<StdForwardList, PmrForwardList>::value, "");
     PmrForwardList d;
     assert(d.get_allocator().resource() == pmr::get_default_resource());
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_list_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_list_synop.pass.cpp
index 3a13f130389..2884a3fbb74 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_list_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_list_synop.pass.cpp
@@ -26,11 +26,13 @@
 
 namespace pmr = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     using StdList = std::list<int, pmr::polymorphic_allocator<int>>;
     using PmrList = pmr::list<int>;
     static_assert(std::is_same<StdList, PmrList>::value, "");
     PmrList d;
     assert(d.get_allocator().resource() == pmr::get_default_resource());
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_map_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_map_synop.pass.cpp
index 507aaf7b7bc..5b221c539ee 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_map_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_map_synop.pass.cpp
@@ -30,7 +30,7 @@
 
 namespace pmr = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     using K = int;
     using V = char;
@@ -65,4 +65,6 @@ int main()
         pmr::multimap<int, int> m;
         assert(m.get_allocator().resource() == pmr::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_regex_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_regex_synop.pass.cpp
index ffc6f4239d5..95f6d6f0c1e 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_regex_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_regex_synop.pass.cpp
@@ -40,7 +40,7 @@ void test_match_result_typedef() {
     static_assert(std::is_same<PmrMR, PmrTypedef>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     {
         test_match_result_typedef<const char*, pmr::cmatch>();
@@ -53,4 +53,6 @@ int main()
         pmr::smatch s;
         assert(s.get_allocator().resource() == pmr::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_set_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_set_synop.pass.cpp
index 42b6f33ebce..4ee12d61a0d 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_set_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_set_synop.pass.cpp
@@ -30,7 +30,7 @@
 
 namespace pmr = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     using V = char;
     using DC = std::less<V>;
@@ -63,4 +63,6 @@ int main()
         pmr::multiset<int> m;
         assert(m.get_allocator().resource() == pmr::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_string_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_string_synop.pass.cpp
index 081466dbc77..3a730fafea1 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_string_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_string_synop.pass.cpp
@@ -50,7 +50,7 @@ void test_basic_string_alias() {
     static_assert(std::is_same<StdStr, PmrStr>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     {
         test_string_typedef<char,     pmr::string>();
@@ -69,4 +69,6 @@ int main()
         pmr::string s;
         assert(s.get_allocator().resource() == pmr::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_map_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_map_synop.pass.cpp
index 190cfd40fec..8b07d68a016 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_map_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_map_synop.pass.cpp
@@ -36,7 +36,7 @@ struct MyHash : std::hash<T> {};
 template <class T>
 struct MyPred : std::equal_to<T> {};
 
-int main()
+int main(int, char**)
 {
     using K = int;
     using V = char;
@@ -83,4 +83,6 @@ int main()
         pmr::unordered_multimap<int, int> m;
         assert(m.get_allocator().resource() == pmr::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_set_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_set_synop.pass.cpp
index 7a795d08fae..c4238dee184 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_set_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_unordered_set_synop.pass.cpp
@@ -36,7 +36,7 @@ struct MyHash : std::hash<T> {};
 template <class T>
 struct MyPred : std::equal_to<T> {};
 
-int main()
+int main(int, char**)
 {
     using V = char;
     using DH = std::hash<V>;
@@ -81,4 +81,6 @@ int main()
         pmr::unordered_multiset<int> m;
         assert(m.get_allocator().resource() == pmr::get_default_resource());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_vector_synop.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_vector_synop.pass.cpp
index ea8d11e1473..a5c0e8bbd3c 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.aliases/header_vector_synop.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.aliases/header_vector_synop.pass.cpp
@@ -26,11 +26,13 @@
 
 namespace pmr = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     using StdVector = std::vector<int, pmr::polymorphic_allocator<int>>;
     using PmrVector = pmr::vector<int>;
     static_assert(std::is_same<StdVector, PmrVector>::value, "");
     PmrVector d;
     assert(d.get_allocator().resource() == pmr::get_default_resource());
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.global/default_resource.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.global/default_resource.pass.cpp
index 91a9027a2cc..c3bf1a2fcfd 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.global/default_resource.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.global/default_resource.pass.cpp
@@ -36,7 +36,7 @@
 
 using namespace std::experimental::pmr;
 
-int main() {
+int main(int, char**) {
     TestResource R;
     { // Test (A) and (B)
         memory_resource* p = get_default_resource();
@@ -70,4 +70,6 @@ int main() {
         static_assert(noexcept(set_default_resource(nullptr)),
                       "set_default_resource() must be noexcept");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp
index 958490d78c6..da340d7a000 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp
@@ -92,10 +92,12 @@ void test_allocate_deallocate()
 
 }
 
-int main()
+int main(int, char**)
 {
     static_assert(noexcept(ex::new_delete_resource()), "Must be noexcept");
     test_return();
     test_equality();
     test_allocate_deallocate();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp
index aab29728f8f..f7111b49325 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp
@@ -108,10 +108,12 @@ void test_deallocate()
     assert(globalMemCounter.checkDeleteArrayCalledEq(0));
 }
 
-int main()
+int main(int, char**)
 {
     test_return();
     test_equality();
     test_allocate();
     test_deallocate();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource.synop/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.synop/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/experimental/memory/memory.resource.synop/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.synop/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/construct.fail.cpp b/libcxx/test/std/experimental/memory/memory.resource/construct.fail.cpp
index d23f583505e..f4d57be8dc6 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/construct.fail.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/construct.fail.cpp
@@ -18,7 +18,9 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     ex::memory_resource m; // expected-error {{variable type 'ex::memory_resource' is an abstract class}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/equal.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/equal.pass.cpp
index 774e6c7e76c..f9d4d5beb91 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/equal.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/equal.pass.cpp
@@ -21,7 +21,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     // check return types
     {
@@ -72,4 +72,6 @@ int main()
         assert(r1.checkIsEqualCalledEq(1));
         assert(r2.checkIsEqualCalledEq(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/not_equal.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/not_equal.pass.cpp
index c9ce3913818..037bb1a9613 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/not_equal.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.eq/not_equal.pass.cpp
@@ -20,7 +20,7 @@
 
 namespace ex = std::experimental::pmr;
 
-int main()
+int main(int, char**)
 {
     // check return types
     {
@@ -71,4 +71,6 @@ int main()
         assert(!(mr2 != mr1));
         assert(r1.checkIsEqualCalledEq(0));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.overview/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.overview/nothing_to_do.pass.cpp
index 98c4bdd4f1c..796f3c353ba 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.overview/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.overview/nothing_to_do.pass.cpp
@@ -6,4 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.priv/protected_members.fail.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.priv/protected_members.fail.cpp
index 15db1b365b4..faa3a252e84 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.priv/protected_members.fail.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.priv/protected_members.fail.cpp
@@ -18,9 +18,11 @@
 
 namespace ex = std::experimental::pmr;
 
-int main() {
+int main(int, char**) {
     ex::memory_resource *m = ex::new_delete_resource();
     m->do_allocate(0, 0); // expected-error{{'do_allocate' is a protected member}}
     m->do_deallocate(nullptr, 0, 0); // expected-error{{'do_deallocate' is a protected member}}
     m->do_is_equal(*m); // expected-error{{'do_is_equal' is a protected member}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/allocate.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/allocate.pass.cpp
index 77aa1da3c83..38f49743cca 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/allocate.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/allocate.pass.cpp
@@ -31,7 +31,7 @@
 
 using std::experimental::pmr::memory_resource;
 
-int main()
+int main(int, char**)
 {
     TestResource R(42);
     auto& P = R.getController();
@@ -85,4 +85,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/deallocate.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/deallocate.pass.cpp
index c76036811b3..e8c2d5bfff1 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/deallocate.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/deallocate.pass.cpp
@@ -30,7 +30,7 @@
 
 using std::experimental::pmr::memory_resource;
 
-int main()
+int main(int, char**)
 {
     NullResource R(42);
     auto& P = R.getController();
@@ -70,4 +70,6 @@ int main()
         assert(P.dealloc_count == 2);
         assert(P.checkDealloc(p, s, a));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/dtor.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/dtor.pass.cpp
index db9156834fe..be5ea2fb008 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/dtor.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/dtor.pass.cpp
@@ -26,7 +26,7 @@
 
 using std::experimental::pmr::memory_resource;
 
-int main()
+int main(int, char**)
 {
     static_assert(
         std::has_virtual_destructor<memory_resource>::value
@@ -55,4 +55,6 @@ int main()
         assert(TR::resource_constructed == 1);
         assert(TR::resource_destructed == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/is_equal.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/is_equal.pass.cpp
index e2ff9d9d122..f0e51787085 100644
--- a/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/is_equal.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource/memory.resource.public/is_equal.pass.cpp
@@ -28,7 +28,7 @@
 
 using std::experimental::pmr::memory_resource;
 
-int main()
+int main(int, char**)
 {
     {
         memory_resource const* r1 = nullptr;
@@ -89,4 +89,6 @@ int main()
         assert(P2.checkIsEqualCalledEq(1));
         assert(P1.checkIsEqualCalledEq(1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/memory/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/memory/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/experimental/memory/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/memory/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/nothing_to_do.pass.cpp
index 98c4bdd4f1c..796f3c353ba 100644
--- a/libcxx/test/std/experimental/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/nothing_to_do.pass.cpp
@@ -6,4 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.abi/vector_extension.pass.cpp b/libcxx/test/std/experimental/simd/simd.abi/vector_extension.pass.cpp
index a17e96df6a0..6bd56d2dda7 100644
--- a/libcxx/test/std/experimental/simd/simd.abi/vector_extension.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.abi/vector_extension.pass.cpp
@@ -63,4 +63,6 @@ static_assert(std::is_same<ex::simd_abi::compatible<int8_t>,
                            ex::__simd_abi<ex::_StorageKind::_Array, 16>>::value,
               "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.access/default.pass.cpp b/libcxx/test/std/experimental/simd/simd.access/default.pass.cpp
index 9b179f2c79d..6e6e4fe9e9a 100644
--- a/libcxx/test/std/experimental/simd/simd.access/default.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.access/default.pass.cpp
@@ -210,7 +210,9 @@ void test_access() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_access<ex::native_simd<int>>();
   test_access<ex::fixed_size_simd<int, 4>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.casts/simd_cast.pass.cpp b/libcxx/test/std/experimental/simd/simd.casts/simd_cast.pass.cpp
index 7f70c5b02bb..ec4a32bf9d7 100644
--- a/libcxx/test/std/experimental/simd/simd.casts/simd_cast.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.casts/simd_cast.pass.cpp
@@ -42,4 +42,6 @@ static_assert(
         ex::simd<int64_t, ex::simd_abi::scalar>>::value,
     "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp b/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp
index a01e423583b..40922ce1153 100644
--- a/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp
@@ -37,4 +37,6 @@ static_assert(
         ex::simd<float, ex::simd_abi::scalar>>::value,
     "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.cons/broadcast.pass.cpp b/libcxx/test/std/experimental/simd/simd.cons/broadcast.pass.cpp
index 2e34bb9acf0..25dd8a4c534 100644
--- a/libcxx/test/std/experimental/simd/simd.cons/broadcast.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.cons/broadcast.pass.cpp
@@ -78,8 +78,10 @@ void test_broadcast() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_broadcast<ex::native_simd<int>>();
   test_broadcast<ex::fixed_size_simd<int, 4>>();
   test_broadcast<ex::fixed_size_simd<int, 15>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.cons/default.pass.cpp b/libcxx/test/std/experimental/simd/simd.cons/default.pass.cpp
index 2e64a821964..6eebe0ec0cf 100644
--- a/libcxx/test/std/experimental/simd/simd.cons/default.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.cons/default.pass.cpp
@@ -18,10 +18,12 @@
 
 namespace ex = std::experimental::parallelism_v2;
 
-int main() {
+int main(int, char**) {
   static_assert(ex::native_simd<int32_t>().size() > 0, "");
   static_assert(ex::fixed_size_simd<int32_t, 4>().size() == 4, "");
   static_assert(ex::fixed_size_simd<int32_t, 5>().size() == 5, "");
   static_assert(ex::fixed_size_simd<int32_t, 1>().size() == 1, "");
   static_assert(ex::fixed_size_simd<char, 32>().size() == 32, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.cons/generator.pass.cpp b/libcxx/test/std/experimental/simd/simd.cons/generator.pass.cpp
index 542715de66b..19880e9d301 100644
--- a/libcxx/test/std/experimental/simd/simd.cons/generator.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.cons/generator.pass.cpp
@@ -82,9 +82,11 @@ void test_generator() {
   }
 }
 
-int main() {
+int main(int, char**) {
   // TODO: adjust the tests when this assertion fails.
   assert(ex::native_simd<int32_t>::size() >= 4);
   test_generator<ex::native_simd<int32_t>>();
   test_generator<ex::fixed_size_simd<int32_t, 4>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.cons/load.pass.cpp b/libcxx/test/std/experimental/simd/simd.cons/load.pass.cpp
index 3056e47fd4b..9440d5aefa3 100644
--- a/libcxx/test/std/experimental/simd/simd.cons/load.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.cons/load.pass.cpp
@@ -107,11 +107,13 @@ void test_converting_load_ctor() {
   assert(a[3] == 8);
 }
 
-int main() {
+int main(int, char**) {
   // TODO: adjust the tests when this assertion fails.
   assert(ex::native_simd<int32_t>::size() >= 4);
   test_load_ctor<ex::native_simd<int32_t>>();
   test_load_ctor<ex::fixed_size_simd<int32_t, 4>>();
   test_converting_load_ctor<ex::native_simd<int32_t>>();
   test_converting_load_ctor<ex::fixed_size_simd<int32_t, 4>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.mem/load.pass.cpp b/libcxx/test/std/experimental/simd/simd.mem/load.pass.cpp
index 9bda07ee9ea..1a56161c5fb 100644
--- a/libcxx/test/std/experimental/simd/simd.mem/load.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.mem/load.pass.cpp
@@ -111,11 +111,13 @@ void test_converting_load() {
   assert(a[3] == 8);
 }
 
-int main() {
+int main(int, char**) {
   // TODO: adjust the tests when this assertion fails.
   assert(ex::native_simd<int32_t>::size() >= 4);
   test_load<ex::native_simd<int32_t>>();
   test_load<ex::fixed_size_simd<int32_t, 4>>();
   test_converting_load<ex::native_simd<int32_t>>();
   test_converting_load<ex::fixed_size_simd<int32_t, 4>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.mem/store.pass.cpp b/libcxx/test/std/experimental/simd/simd.mem/store.pass.cpp
index 3faf400006a..3cc3d1fa14d 100644
--- a/libcxx/test/std/experimental/simd/simd.mem/store.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.mem/store.pass.cpp
@@ -85,10 +85,12 @@ void test_converting_store() {
   assert(buffer[3] == 8.);
 }
 
-int main() {
+int main(int, char**) {
   // TODO: adjust the tests when this assertion fails.
   test_store<ex::native_simd<int32_t>>();
   test_store<ex::fixed_size_simd<int32_t, 4>>();
   test_converting_store<ex::native_simd<int32_t>>();
   test_converting_store<ex::fixed_size_simd<int32_t, 4>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/simd/simd.traits/abi_for_size.pass.cpp b/libcxx/test/std/experimental/simd/simd.traits/abi_for_size.pass.cpp
index a2206780fc7..2bf28dc8a21 100644
--- a/libcxx/test/std/experimental/simd/simd.traits/abi_for_size.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.traits/abi_for_size.pass.cpp
@@ -28,4 +28,6 @@ static_assert(std::is_same<ex::abi_for_size_t<int, 4>,
                            ex::simd_abi::fixed_size<4>>::value,
               "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.traits/is_abi_tag.pass.cpp b/libcxx/test/std/experimental/simd/simd.traits/is_abi_tag.pass.cpp
index f07fca8296a..db98dae2b67 100644
--- a/libcxx/test/std/experimental/simd/simd.traits/is_abi_tag.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.traits/is_abi_tag.pass.cpp
@@ -109,4 +109,6 @@ static_assert(!ex::is_abi_tag_v<ex::simd<float>>, "");
 static_assert(!ex::is_abi_tag_v<ex::simd_mask<int>>, "");
 static_assert(!ex::is_abi_tag_v<ex::simd_mask<float>>, "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.traits/is_simd.pass.cpp b/libcxx/test/std/experimental/simd/simd.traits/is_simd.pass.cpp
index 46326ab5fa1..c465f0de681 100644
--- a/libcxx/test/std/experimental/simd/simd.traits/is_simd.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.traits/is_simd.pass.cpp
@@ -125,4 +125,6 @@ static_assert(!ex::is_simd_v<ex::simd_mask<int>>, "");
 static_assert(!ex::is_simd_v<ex::simd_mask<float>>, "");
 static_assert(!ex::is_simd_v<UserType>, "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.traits/is_simd_flag_type.pass.cpp b/libcxx/test/std/experimental/simd/simd.traits/is_simd_flag_type.pass.cpp
index d91d906cace..5fa208a3be7 100644
--- a/libcxx/test/std/experimental/simd/simd.traits/is_simd_flag_type.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.traits/is_simd_flag_type.pass.cpp
@@ -47,4 +47,6 @@ static_assert(!ex::is_simd_flag_type_v<UserType>, "");
 static_assert(!ex::is_simd_flag_type_v<ex::simd<int8_t>>, "");
 static_assert(!ex::is_simd_flag_type_v<ex::simd_mask<int8_t>>, "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/simd/simd.traits/is_simd_mask.pass.cpp b/libcxx/test/std/experimental/simd/simd.traits/is_simd_mask.pass.cpp
index 5346afef5af..348f2bfdfc3 100644
--- a/libcxx/test/std/experimental/simd/simd.traits/is_simd_mask.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.traits/is_simd_mask.pass.cpp
@@ -148,4 +148,6 @@ static_assert(!ex::is_simd_mask_v<ex::simd<int>>, "");
 static_assert(!ex::is_simd_mask_v<ex::simd<float>>, "");
 static_assert(!ex::is_simd_mask_v<UserType>, "");
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp b/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp
index 658bf0c1209..3ad12b617ae 100644
--- a/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp
@@ -33,7 +33,9 @@ void test() {
     static_assert( std::is_same<Res, typename ex::detected_or_t<double, hasFoo, T>      >::value, "" );
 }
 
-int main () {
+int main(int, char**) {
     test<yesFoo, int>();
     test<noFoo, double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp b/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp
index 7d3304fbcb4..ebb7ecc7d9c 100644
--- a/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp
@@ -40,8 +40,10 @@ void test() {
     static_assert( std::is_same<Res, typename ex::detected_t<callFoo, T>>::value, "" );
 }
 
-int main () {
+int main(int, char**) {
     test<yesFoo, int>();
     test<noFoo, ex::nonesuch>();  // lookup failure returns nonesuch
     test<wrongFoo, std::string>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp b/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp
index 24c9d701174..60b1acae880 100644
--- a/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp
@@ -29,8 +29,10 @@ void test() {
     static_assert( b == ex::is_detected_v<copy_assign_t, T>, "" );
 }
 
-int main () {
+int main(int, char**) {
     test<int, true>();
     test<std::string, true>();
     test<not_assignable, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp b/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp
index a6252b2458b..0944cb2d070 100644
--- a/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp
@@ -41,9 +41,11 @@ void test() {
     static_assert( b == ex::is_detected_convertible_v<int, callFoo, T>, "" );
 }
 
-int main () {
+int main(int, char**) {
     test<yesFoo, true>();
     test<noFoo, false>();
     test<wrongFoo, false>();
     test<convertibleFoo, true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp b/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp
index c888d436b04..c3156403233 100644
--- a/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp
@@ -40,9 +40,11 @@ void test() {
     static_assert( b == ex::is_detected_exact_v<int, callFoo, T>, "" );
 }
 
-int main () {
+int main(int, char**) {
     test<yesFoo, true>();
     test<noFoo, false>();
     test<wrongFoo, false>();
     test<convertibleFoo, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/nothing_to_do.pass.cpp b/libcxx/test/std/experimental/utilities/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/experimental/utilities/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign.pass.cpp
index 481fd4f8fb0..078c8c7f067 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign.pass.cpp
@@ -20,4 +20,6 @@ using std::experimental::propagate_const;
 
 typedef propagate_const<X> P;
 
-int main() { static_assert(!std::is_assignable<P, const P &>::value, ""); }
+int main(int, char**) { static_assert(!std::is_assignable<P, const P &>::value, ""); 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_element_type.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_element_type.pass.cpp
index 7a0fb47ebe0..512b5998138 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_element_type.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_element_type.pass.cpp
@@ -18,7 +18,7 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<CopyConstructibleFromX> PY;
 
@@ -30,4 +30,6 @@ int main() {
   p = x1;
 
   assert(*p==1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_propagate_const.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_propagate_const.pass.cpp
index 9b6e7045891..0da532ab4a2 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_propagate_const.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_convertible_propagate_const.pass.cpp
@@ -21,4 +21,6 @@ using std::experimental::propagate_const;
 typedef propagate_const<X> PX;
 typedef propagate_const<CopyConstructibleFromX> PY;
 
-int main() { static_assert(!std::is_assignable<PY, const PX &>::value, ""); }
+int main(int, char**) { static_assert(!std::is_assignable<PY, const PX &>::value, ""); 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_element_type.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_element_type.pass.cpp
index d46180ee6f5..896ef9c90b9 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_element_type.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/assign_element_type.pass.cpp
@@ -18,7 +18,7 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -30,4 +30,6 @@ int main() {
   p = x1;
 
   assert(*p==1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign.pass.cpp
index 3aff4598061..f1546afcc5f 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign.pass.cpp
@@ -18,7 +18,7 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -28,4 +28,6 @@ int main() {
   p2=std::move(p1);
 
   assert(*p2==1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible.pass.cpp
index 5fe39a435b9..dfff0bc9350 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible.pass.cpp
@@ -18,7 +18,7 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> PX;
   typedef propagate_const<MoveConstructibleFromX> PY;
@@ -29,4 +29,6 @@ int main() {
   py1=std::move(px2);
 
   assert(*py1==2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible_propagate_const.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible_propagate_const.pass.cpp
index b99a25121a0..894910eaa87 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible_propagate_const.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.assignment/move_assign_convertible_propagate_const.pass.cpp
@@ -18,7 +18,7 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> PX;
   typedef propagate_const<MoveConstructibleFromX> PY;
@@ -29,4 +29,6 @@ int main() {
   py1=std::move(px2);
 
   assert(*py1==2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.explicit.ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.explicit.ctor.pass.cpp
index 10dc724ab58..24e27cb6b56 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.explicit.ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.explicit.ctor.pass.cpp
@@ -20,8 +20,10 @@ using std::experimental::propagate_const;
 
 typedef propagate_const<ExplicitCopyConstructibleFromX> P;
 
-int main() {
+int main(int, char**) {
   static_assert(!std::is_convertible<P, X>::value, "");
   static_assert(std::is_constructible<P, X>::value, "");
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.non-explicit.ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.non-explicit.ctor.pass.cpp
index ec0ad47e713..9cb325db00f 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.non-explicit.ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_element_type.non-explicit.ctor.pass.cpp
@@ -25,7 +25,9 @@ void f(const P& p)
   assert(*p==2);
 }
 
-int main() {
+int main(int, char**) {
   f(X(2));
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.copy_ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.copy_ctor.pass.cpp
index 0320161ba74..e440245b5e4 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.copy_ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.copy_ctor.pass.cpp
@@ -21,5 +21,7 @@ using std::experimental::propagate_const;
 typedef propagate_const<X> PX;
 typedef propagate_const<CopyConstructibleFromX> PY;
 
-int main() { static_assert(!std::is_constructible<PX, PY>::value, ""); }
+int main(int, char**) { static_assert(!std::is_constructible<PX, PY>::value, ""); 
+  return 0;
+}
 
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.explicit.move_ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.explicit.move_ctor.pass.cpp
index aa4f1a3ed62..3166ebe70c1 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.explicit.move_ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.explicit.move_ctor.pass.cpp
@@ -21,7 +21,9 @@ using std::experimental::propagate_const;
 typedef propagate_const<X> PX;
 typedef propagate_const<ExplicitMoveConstructibleFromX> PY;
 
-int main() {
+int main(int, char**) {
   static_assert(!std::is_convertible<PY, PX &&>::value, "");
   static_assert(std::is_constructible<PY, PX &&>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.move_ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.move_ctor.pass.cpp
index 77f8791a396..ea1ac4262f3 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.move_ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/convertible_propagate_const.move_ctor.pass.cpp
@@ -21,10 +21,12 @@ using std::experimental::propagate_const;
 typedef propagate_const<MoveConstructibleFromX> PY;
 typedef propagate_const<X> PX;
 
-int main() {
+int main(int, char**) {
   PX px(1);
   PY py(std::move(px));
 
   assert(*py==1);
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/copy_ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/copy_ctor.pass.cpp
index 0e992a69ba6..7c0558f398f 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/copy_ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/copy_ctor.pass.cpp
@@ -20,4 +20,6 @@ using std::experimental::propagate_const;
 
 typedef propagate_const<X> P;
 
-int main() { static_assert(!std::is_constructible<P, const P &>::value, ""); }
+int main(int, char**) { static_assert(!std::is_constructible<P, const P &>::value, ""); 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.explicit.ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.explicit.ctor.pass.cpp
index 45a3bd363ee..aee637620a7 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.explicit.ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.explicit.ctor.pass.cpp
@@ -20,8 +20,10 @@ using std::experimental::propagate_const;
 
 typedef propagate_const<ExplicitX> P;
 
-int main() {
+int main(int, char**) {
   static_assert(!std::is_convertible<P, int>::value, "");
   static_assert(std::is_constructible<P, int>::value, "");
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.non-explicit.ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.non-explicit.ctor.pass.cpp
index b9f6bad69bb..93e50578a97 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.non-explicit.ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/element_type.non-explicit.ctor.pass.cpp
@@ -24,4 +24,6 @@ void f(const P&)
 {
 }
 
-int main() { f(2); }
+int main(int, char**) { f(2); 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/move_ctor.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/move_ctor.pass.cpp
index 6badeeede2b..662a605f49c 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/move_ctor.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.ctors/move_ctor.pass.cpp
@@ -18,11 +18,13 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
   P p1(2);
   P p2(std::move(p1));
   assert(*p2 == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/dereference.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/dereference.pass.cpp
index 8dffebafa48..4e47bac3715 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/dereference.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/dereference.pass.cpp
@@ -27,7 +27,9 @@ constexpr P f()
   return p;
 }
 
-int main() {
+int main(int, char**) {
   constexpr P p = f();
   static_assert(*p==2,"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/explicit_operator_element_type_ptr.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/explicit_operator_element_type_ptr.pass.cpp
index 53d378391a0..6ce5d407c58 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/explicit_operator_element_type_ptr.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/explicit_operator_element_type_ptr.pass.cpp
@@ -20,4 +20,6 @@ using std::experimental::propagate_const;
 
 typedef propagate_const<X> P;
 
-int main() { static_assert(!std::is_convertible<P, int *>::value, ""); }
+int main(int, char**) { static_assert(!std::is_convertible<P, int *>::value, ""); 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/get.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/get.pass.cpp
index 04fe4add1ed..1a12c3bdd3d 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/get.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/get.pass.cpp
@@ -27,7 +27,9 @@ constexpr P f()
   return p;
 }
 
-int main() {
+int main(int, char**) {
   constexpr P p = f();
   static_assert(*(p.get())==2,"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/op_arrow.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/op_arrow.pass.cpp
index d8ea66e8d92..bdc6c693730 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/op_arrow.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/op_arrow.pass.cpp
@@ -27,7 +27,9 @@ constexpr P f()
   return p;
 }
 
-int main() {
+int main(int, char**) {
   constexpr P p = f();
   static_assert(*(p.operator->())==2,"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/operator_element_type_ptr.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/operator_element_type_ptr.pass.cpp
index 87b68890967..46244b39172 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/operator_element_type_ptr.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.non-const_observers/operator_element_type_ptr.pass.cpp
@@ -18,7 +18,7 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<XWithImplicitIntStarConversion> P;
 
@@ -31,4 +31,6 @@ int main() {
   *ptr_1 = 2;
 
   assert(*ptr_1==2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/dereference.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/dereference.pass.cpp
index c0a5e1e44e5..758bca4694e 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/dereference.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/dereference.pass.cpp
@@ -18,11 +18,13 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
   constexpr P p(1);
 
   static_assert(*p==1,"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/explicit_operator_element_type_ptr.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/explicit_operator_element_type_ptr.pass.cpp
index b7dd8f843a5..1f98f03d2fa 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/explicit_operator_element_type_ptr.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/explicit_operator_element_type_ptr.pass.cpp
@@ -20,6 +20,8 @@ using std::experimental::propagate_const;
 
 typedef propagate_const<X> P;
 
-int main() {
+int main(int, char**) {
   static_assert(!std::is_convertible<const P, const int *>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/get.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/get.pass.cpp
index f424fae6456..71aea68edc2 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/get.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/get.pass.cpp
@@ -18,11 +18,13 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
   constexpr P p(1);
 
   static_assert(*(p.get())==1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/op_arrow.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/op_arrow.pass.cpp
index 14ba32387f8..dcb1b924557 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/op_arrow.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/op_arrow.pass.cpp
@@ -18,11 +18,13 @@
 
 using std::experimental::propagate_const;
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
   constexpr P p(1);
 
   static_assert(*(p.operator->())==1,"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/operator_element_type_ptr.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/operator_element_type_ptr.pass.cpp
index 8c0cb02fc1c..bfd295a1fa0 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/operator_element_type_ptr.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/propagate_const.observers/operator_element_type_ptr.pass.cpp
@@ -24,4 +24,6 @@ constexpr P p(1);
 
 constexpr const int *ptr_1 = p;
 
-int main() { assert(*ptr_1 == 1); }
+int main(int, char**) { assert(*ptr_1 == 1); 
+  return 0;
+}
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/swap.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/swap.pass.cpp
index e6b94957f9d..03b32dd0ec6 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/swap.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.class/swap.pass.cpp
@@ -21,11 +21,13 @@ using std::experimental::propagate_const;
 bool swap_called = false;
 void swap(X &, X &) { swap_called = true; }
 
-int main() {
+int main(int, char**) {
   typedef propagate_const<X> P;
   P p1(1);
   P p2(2);
   p1.swap(p2);
   assert(swap_called);
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/hash.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/hash.pass.cpp
index 76c683458d8..28ac9c22460 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/hash.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/hash.pass.cpp
@@ -31,7 +31,7 @@ template <> struct hash<X>
 };
 } // namespace std
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -40,4 +40,6 @@ int main() {
   auto h = std::hash<P>();
 
   assert(h(p)==99);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/equal_to.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/equal_to.pass.cpp
index 40f4ae7d519..85e40050476 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/equal_to.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/equal_to.pass.cpp
@@ -20,7 +20,7 @@ using std::experimental::propagate_const;
 
 constexpr bool operator==(const X &x1, const X &x2) { return x1.i_ == x2.i_; }
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -32,4 +32,6 @@ int main() {
 
   assert(c(p1_1,p2_1));
   assert(!c(p1_1,p3_2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater.pass.cpp
index f019f07d125..ab7b5e9a21d 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater.pass.cpp
@@ -20,7 +20,7 @@ using std::experimental::propagate_const;
 
 constexpr bool operator>(const X &x1, const X &x2) { return x1.i_ > x2.i_; }
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -34,4 +34,6 @@ int main() {
   assert(!c(p2_1,p1_1));
   assert(!c(p1_1,p3_2));
   assert(c(p3_2,p1_1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater_equal.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater_equal.pass.cpp
index 8f0e0d8cdf9..f30e0e9d22e 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater_equal.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/greater_equal.pass.cpp
@@ -20,7 +20,7 @@ using std::experimental::propagate_const;
 
 constexpr bool operator>=(const X &x1, const X &x2) { return x1.i_ >= x2.i_; }
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -34,4 +34,6 @@ int main() {
   assert(c(p2_1,p1_1));
   assert(!c(p1_1,p3_2));
   assert(c(p3_2,p1_1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less.pass.cpp
index 584f52ba6e2..75afd95e115 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less.pass.cpp
@@ -20,7 +20,7 @@ using std::experimental::propagate_const;
 
 constexpr bool operator<(const X &x1, const X &x2) { return x1.i_ < x2.i_; }
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -34,4 +34,6 @@ int main() {
   assert(!c(p2_1,p1_1));
   assert(c(p1_1,p3_2));
   assert(!c(p3_2,p1_1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less_equal.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less_equal.pass.cpp
index 4eb25db29b3..4f6523a320f 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less_equal.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/less_equal.pass.cpp
@@ -20,7 +20,7 @@ using std::experimental::propagate_const;
 
 constexpr bool operator<=(const X &x1, const X &x2) { return x1.i_ <= x2.i_; }
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -34,4 +34,6 @@ int main() {
   assert(c(p2_1,p1_1));
   assert(c(p1_1,p3_2));
   assert(!c(p3_2,p1_1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/not_equal_to.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/not_equal_to.pass.cpp
index 52eadc4b31d..1c303ae28db 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/not_equal_to.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.comparison_function_objects/not_equal_to.pass.cpp
@@ -20,7 +20,7 @@ using std::experimental::propagate_const;
 
 constexpr bool operator!=(const X &x1, const X &x2) { return x1.i_ != x2.i_; }
 
-int main() {
+int main(int, char**) {
 
   typedef propagate_const<X> P;
 
@@ -32,4 +32,6 @@ int main() {
 
   assert(!c(p1_1,p2_1));
   assert(c(p1_1,p3_2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/equal.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/equal.pass.cpp
index 696330a426c..dafc355a48e 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/equal.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/equal.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool operator==(const nullptr_t &, const X &) {
   return false;
 }
 
-int main() {
+int main(int, char**) {
   constexpr X x1_1(1);
   constexpr X x2_1(1);
   constexpr X x3_2(2);
@@ -60,4 +60,6 @@ int main() {
 
   static_assert(!(p1_1==nullptr),"");
   static_assert(!(nullptr==p1_1),"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_equal.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_equal.pass.cpp
index 8c214f745c8..36f3747303e 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_equal.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_equal.pass.cpp
@@ -24,7 +24,7 @@ constexpr bool operator>=(const X &lhs, const X &rhs) {
   return lhs.i_ >= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   constexpr X x1_1(1);
   constexpr X x2_1(1);
   constexpr X x3_2(2);
@@ -50,4 +50,6 @@ int main() {
   static_assert(x1_1 >= p2_1, "");
   static_assert(!(x1_1 >= p3_2), "");
   static_assert(x3_2 >= p1_1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_than.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_than.pass.cpp
index fb679978595..6abadb39b23 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_than.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/greater_than.pass.cpp
@@ -24,7 +24,7 @@ constexpr bool operator>(const X &lhs, const X &rhs) {
   return lhs.i_ > rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   constexpr X x1_1(1);
   constexpr X x2_1(1);
   constexpr X x3_2(2);
@@ -46,4 +46,6 @@ int main() {
 
   static_assert(!(x1_1 > p2_1), "");
   static_assert(x3_2 > p1_1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_equal.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_equal.pass.cpp
index a1d5b3d9e51..703faed74e5 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_equal.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_equal.pass.cpp
@@ -24,7 +24,7 @@ constexpr bool operator<=(const X &lhs, const X &rhs) {
   return lhs.i_ <= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   constexpr X x1_1(1);
   constexpr X x2_1(1);
   constexpr X x3_2(2);
@@ -51,4 +51,6 @@ int main() {
   static_assert(x1_1 <= p3_2, "");
   static_assert(!(x3_2 <= p1_1), "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_than.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_than.pass.cpp
index 00bf157d962..7481418d384 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_than.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/less_than.pass.cpp
@@ -24,7 +24,7 @@ constexpr bool operator<(const X &lhs, const X &rhs) {
   return lhs.i_ < rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   constexpr X x1_1(1);
   constexpr X x2_1(1);
   constexpr X x3_2(2);
@@ -46,4 +46,6 @@ int main() {
 
   static_assert(!(p1_1 < x1_1), "");
   static_assert(p1_1 < x3_2, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/not_equal.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/not_equal.pass.cpp
index ba30912dd24..ebfc6231557 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/not_equal.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/propagate_const.relops/not_equal.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool operator!=(const nullptr_t &, const X &) {
   return true;
 }
 
-int main() {
+int main(int, char**) {
   constexpr X x1_1(1);
   constexpr X x2_1(1);
   constexpr X x3_2(2);
@@ -58,4 +58,6 @@ int main() {
 
   static_assert(p1_1!=nullptr,"");
   static_assert(nullptr!=p1_1,"");
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/swap.pass.cpp b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/swap.pass.cpp
index 1df35dd8886..84923f78dc1 100644
--- a/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/swap.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/propagate_const/propagate_const.nonmembers/swap.pass.cpp
@@ -21,10 +21,12 @@ using std::experimental::propagate_const;
 bool swap_called = false;
 void swap(X &, X &) { swap_called = true; }
 
-int main() {
+int main(int, char**) {
   typedef propagate_const<X> P;
   P p1(1);
   P p2(2);
   swap(p1, p2);
   assert(swap_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/utility/utility.erased.type/erased_type.pass.cpp b/libcxx/test/std/experimental/utilities/utility/utility.erased.type/erased_type.pass.cpp
index 9c3ac0cc98c..36bf4f793b4 100644
--- a/libcxx/test/std/experimental/utilities/utility/utility.erased.type/erased_type.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/utility/utility.erased.type/erased_type.pass.cpp
@@ -10,8 +10,10 @@
 
 #include <experimental/utility>
 
-int main()
+int main(int, char**)
 {
   std::experimental::erased_type e;
   ((void)e);
+
+  return 0;
 }
diff --git a/libcxx/test/std/experimental/utilities/utility/utility.synop/includes.pass.cpp b/libcxx/test/std/experimental/utilities/utility/utility.synop/includes.pass.cpp
index 45140f33302..ddf053f2429 100644
--- a/libcxx/test/std/experimental/utilities/utility/utility.synop/includes.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/utility/utility.synop/includes.pass.cpp
@@ -14,6 +14,8 @@
 #   error "<experimental/utility> must include <utility>"
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/c.files/cinttypes.pass.cpp b/libcxx/test/std/input.output/file.streams/c.files/cinttypes.pass.cpp
index 675c5751650..e9e32bb6734 100644
--- a/libcxx/test/std/input.output/file.streams/c.files/cinttypes.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/c.files/cinttypes.pass.cpp
@@ -877,7 +877,7 @@ template <class T> void test()
     ((void)t); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test<std::int8_t >();
     test<std::int16_t>();
@@ -927,4 +927,6 @@ int main()
     static_assert((std::is_same<decltype(std::strtoumax("", (char**)0, 0)), std::uintmax_t>::value), "");
     static_assert((std::is_same<decltype(std::wcstoimax(L"", (wchar_t**)0, 0)), std::intmax_t>::value), "");
     static_assert((std::is_same<decltype(std::wcstoumax(L"", (wchar_t**)0, 0)), std::uintmax_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp b/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp
index 95a5cb69512..af8dc97a5e8 100644
--- a/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp
@@ -85,7 +85,7 @@
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
 #endif
 
-int main()
+int main(int, char**)
 {
     std::FILE* fp = 0;
     std::fpos_t fpos = std::fpos_t();
@@ -154,4 +154,6 @@ int main()
     static_assert((std::is_same<decltype(std::puts("")), int>::value), "");
     static_assert((std::is_same<decltype(std::vprintf(" ",va)), int>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/c.files/gets.fail.cpp b/libcxx/test/std/input.output/file.streams/c.files/gets.fail.cpp
index 0772dc9f0fc..dae0e42ff34 100644
--- a/libcxx/test/std/input.output/file.streams/c.files/gets.fail.cpp
+++ b/libcxx/test/std/input.output/file.streams/c.files/gets.fail.cpp
@@ -13,7 +13,9 @@
 
 #include <cstdio>
 
-int main()
+int main(int, char**)
 {
     (void) std::gets((char *) NULL);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/member_swap.pass.cpp
index b6890b8717d..9bfcec0a48f 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/member_swap.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -50,4 +50,6 @@ int main()
         assert(f2.sgetc() == L'2');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/move_assign.pass.cpp
index 0acda35b080..a397e6cc138 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/move_assign.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -52,4 +52,6 @@ int main()
         assert(f2.sgetc() == L'2');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/nonmember_swap.pass.cpp
index 6fd1d2bb471..f23c119af90 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/nonmember_swap.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -52,4 +52,6 @@ int main()
         assert(f2.sgetc() == L'2');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/default.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/default.pass.cpp
index d9230b04527..5efbb03c8a6 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::filebuf f;
@@ -26,4 +26,6 @@ int main()
         std::wfilebuf f;
         assert(!f.is_open());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/move.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/move.pass.cpp
index ad4d37dad63..922e514d7f4 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.cons/move.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -50,4 +50,6 @@ int main()
         assert(f2.sgetc() == L'2');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_path.pass.cpp
index 7f7ce344f86..ea244e1a32d 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_path.pass.cpp
@@ -19,7 +19,7 @@
 
 namespace fs = std::filesystem;
 
-int main() {
+int main(int, char**) {
 
   fs::path p = get_temp_file_name();
   {
@@ -52,4 +52,6 @@ int main() {
     assert(f.sbumpc() == L'3');
   }
   remove(p.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_pointer.pass.cpp
index fc3dd6d01cd..bd662a9f7f8 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/open_pointer.pass.cpp
@@ -14,7 +14,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -47,4 +47,6 @@ int main()
         assert(f.sbumpc() == L'3');
     }
     remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/overflow.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/overflow.pass.cpp
index 0aeb505c75c..6636a422332 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/overflow.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/overflow.pass.cpp
@@ -36,7 +36,7 @@ struct test_buf
     virtual int_type overflow(int_type c = traits_type::eof()) {return base::overflow(c);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test_buf<char> f;
@@ -140,4 +140,6 @@ int main()
         assert(f.sbumpc() == -1);
     }
     std::remove("overflow.dat");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp
index e711b0c9b5c..728eec2938e 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp
@@ -32,7 +32,7 @@ struct test_buf
     virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test_buf<char> f;
@@ -60,4 +60,6 @@ int main()
             assert(f.sgetc() == '2');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/seekoff.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/seekoff.pass.cpp
index 9126b3396d7..6f50357a093 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/seekoff.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/seekoff.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         char buf[10];
@@ -62,4 +62,6 @@ int main()
         assert(f.sgetc() == L'l');
     }
     std::remove("seekoff.dat");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/underflow.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/underflow.pass.cpp
index 8859b07969d..47760a91627 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/underflow.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/underflow.pass.cpp
@@ -36,7 +36,7 @@ struct test_buf
     virtual int_type underflow() {return base::underflow();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test_buf<char> f;
@@ -121,4 +121,6 @@ int main()
         assert(f.sbumpc() == 0x4E53);
         assert(f.sbumpc() == static_cast<Traits::int_type>(-1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/filebuf/types.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/filebuf/types.pass.cpp
index e0c95f50a2d..40c010f6f70 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/filebuf/types.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/filebuf/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_streambuf<char>, std::basic_filebuf<char> >::value), "");
     static_assert((std::is_same<std::basic_filebuf<char>::char_type, char>::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::basic_filebuf<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_filebuf<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_filebuf<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/member_swap.pass.cpp
index 312a68d8307..7c94de924d9 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/member_swap.pass.cpp
@@ -35,7 +35,7 @@ std::pair<std::string, std::string> get_temp_file_names() {
   return names;
 }
 
-int main()
+int main(int, char**)
 {
     std::pair<std::string, std::string> temp_files = get_temp_file_names();
     std::string& temp1 = temp_files.first;
@@ -87,4 +87,6 @@ int main()
     }
     std::remove(temp1.c_str());
     std::remove(temp2.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/move_assign.pass.cpp
index 4ee860a8e9f..d2cc6ce722f 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/move_assign.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -46,4 +46,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/nonmember_swap.pass.cpp
index 5a2d826bea6..071ca5d85e7 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.assign/nonmember_swap.pass.cpp
@@ -37,7 +37,7 @@ std::pair<std::string, std::string> get_temp_file_names() {
   return names;
 }
 
-int main()
+int main(int, char**)
 {
     std::pair<std::string, std::string> temp_files = get_temp_file_names();
     std::string& temp1 = temp_files.first;
@@ -89,4 +89,6 @@ int main()
     }
     std::remove(temp1.c_str());
     std::remove(temp2.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/default.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/default.pass.cpp
index ede9fd2393a..b38bbb4431f 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         std::fstream fs;
@@ -24,4 +24,6 @@ int main()
     {
         std::wfstream fs;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/move.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/move.pass.cpp
index a213cc64308..fb639f1c50b 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/move.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -44,4 +44,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/path.pass.cpp
index f63ae6bddbb..d86b4b6ccf8 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/path.pass.cpp
@@ -23,7 +23,7 @@
 
 namespace fs = std::filesystem;
 
-int main() {
+int main(int, char**) {
   fs::path p = get_temp_file_name();
   {
     std::fstream fs(p, std::ios_base::in | std::ios_base::out |
@@ -45,4 +45,6 @@ int main() {
     assert(x == 3.25);
   }
   std::remove(p.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/pointer.pass.cpp
index 07a6a41134f..4cade955b9b 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/pointer.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -40,4 +40,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/string.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/string.pass.cpp
index 36546035cce..15a2c702393 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/string.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -42,4 +42,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/close.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/close.pass.cpp
index 818f73be8f0..94a06c4670c 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/close.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/close.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -38,4 +38,6 @@ int main()
         assert(!fs.is_open());
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_path.pass.cpp
index d6722076a97..799829e2bb2 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_path.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main() {
+int main(int, char**) {
   std::filesystem::path p = get_temp_file_name();
   {
     std::fstream stream;
@@ -48,4 +48,6 @@ int main() {
     assert(x == 3.25);
   }
   std::remove(p.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_pointer.pass.cpp
index 07f5c18f561..32f1d0096a3 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_pointer.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -46,4 +46,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_string.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_string.pass.cpp
index 4bc436b3822..90cd5611701 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_string.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/open_string.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -46,4 +46,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/rdbuf.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/rdbuf.pass.cpp
index ecbc15bc3e5..0f39fc63b62 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.members/rdbuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::fstream fs;
@@ -26,4 +26,6 @@ int main()
         std::wfstream fs;
         assert(fs.rdbuf());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream/types.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream/types.pass.cpp
index 3f81e18f4ba..783cfa3a736 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/fstream/types.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_iostream<char>, std::basic_fstream<char> >::value), "");
     static_assert((std::is_same<std::basic_fstream<char>::char_type, char>::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::basic_fstream<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_fstream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_fstream<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/member_swap.pass.cpp
index e30a9c0600d..17b88140d54 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs1("test.dat");
@@ -38,4 +38,6 @@ int main()
         fs2 >> x;
         assert(x == 3.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/move_assign.pass.cpp
index 9ccd54eec8f..d5fe0984ee6 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/move_assign.pass.cpp
@@ -18,7 +18,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fso("test.dat");
@@ -36,4 +36,6 @@ int main()
         fs >> x;
         assert(x == 3.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/nonmember_swap.pass.cpp
index c008fe50fb7..c4cd592d11e 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.assign/nonmember_swap.pass.cpp
@@ -17,7 +17,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs1("test.dat");
@@ -39,4 +39,6 @@ int main()
         fs2 >> x;
         assert(x == 3.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/default.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/default.pass.cpp
index 896903d36d2..7e76d6f8aef 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs;
@@ -24,4 +24,6 @@ int main()
     {
         std::wifstream fs;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/move.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/move.pass.cpp
index c7e389e3a70..d8a58ac53ce 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fso("test.dat");
@@ -34,4 +34,6 @@ int main()
         fs >> x;
         assert(x == 3.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/path.pass.cpp
index 7d6da5b271e..8a3a361bb39 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/path.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace fs = std::filesystem;
 
-int main() {
+int main(int, char**) {
   {
     fs::path p;
     static_assert(!std::is_convertible<fs::path, std::ifstream>::value,
@@ -49,4 +49,6 @@ int main() {
   // std::wifstream(const fs::path&, std::ios_base::openmode) is tested in
   // test/std/input.output/file.streams/fstreams/ofstream.cons/string.pass.cpp
   // which creates writable files.
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/pointer.pass.cpp
index 6e0bb2984cc..d44b3be75d1 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/pointer.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs("test.dat");
@@ -36,4 +36,6 @@ int main()
     // std::wifstream(const char*, std::ios_base::openmode) is tested in
     // test/std/input.output/file.streams/fstreams/ofstream.cons/pointer.pass.cpp
     // which creates writable files.
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/string.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/string.pass.cpp
index a0d90e25595..c4e979e30c6 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.cons/string.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs(std::string("test.dat"));
@@ -36,4 +36,6 @@ int main()
     // std::wifstream(const std::string&, std::ios_base::openmode) is tested in
     // test/std/input.output/file.streams/fstreams/ofstream.cons/string.pass.cpp
     // which creates writable files.
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/close.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/close.pass.cpp
index 609ca4ac158..e72bd548763 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/close.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/close.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs;
@@ -34,4 +34,6 @@ int main()
         fs.close();
         assert(!fs.is_open());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_path.pass.cpp
index 4432ea5c621..bce5fb97dd1 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_path.pass.cpp
@@ -19,7 +19,7 @@
 #include <filesystem>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   {
     std::ifstream fs;
     assert(!fs.is_open());
@@ -44,4 +44,6 @@ int main() {
     fs >> c;
     assert(c == L'r');
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_pointer.pass.cpp
index 3a12c985291..50ec53fdc78 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_pointer.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs;
@@ -42,4 +42,6 @@ int main()
         fs >> c;
         assert(c == L'r');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_string.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_string.pass.cpp
index e6759ed8cae..155ae0e631d 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_string.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/open_string.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs;
@@ -42,4 +42,6 @@ int main()
         fs >> c;
         assert(c == L'r');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/rdbuf.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/rdbuf.pass.cpp
index ea64139f13e..455d2274e2b 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/rdbuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream fs("test.dat");
@@ -28,4 +28,6 @@ int main()
         std::wfilebuf* fb = fs.rdbuf();
         assert(fb->sgetc() == L'r');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream/types.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream/types.pass.cpp
index a3b441f9386..620c3960895 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream/types.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_istream<char>, std::basic_ifstream<char> >::value), "");
     static_assert((std::is_same<std::basic_ifstream<char>::char_type, char>::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::basic_ifstream<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_ifstream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_ifstream<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/member_swap.pass.cpp
index 89e32e97f76..fcfb94ecf20 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/member_swap.pass.cpp
@@ -35,7 +35,7 @@ std::pair<std::string, std::string> get_temp_file_names() {
   return names;
 }
 
-int main()
+int main(int, char**)
 {
     std::pair<std::string, std::string> temp_files = get_temp_file_names();
     std::string& temp1 = temp_files.first;
@@ -95,4 +95,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp2.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/move_assign.pass.cpp
index 1eba0d576a0..fbc3bf59738 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/move_assign.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -48,4 +48,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/nonmember_swap.pass.cpp
index 4190db3a6c1..3cbf508d94e 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.assign/nonmember_swap.pass.cpp
@@ -36,7 +36,7 @@ std::pair<std::string, std::string> get_temp_file_names() {
   return names;
 }
 
-int main()
+int main(int, char**)
 {
     std::pair<std::string, std::string> temp_files = get_temp_file_names();
     std::string& temp1 = temp_files.first;
@@ -96,4 +96,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp2.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/default.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/default.pass.cpp
index f87bb1e7965..baa4bfe9d8a 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         std::ofstream fs;
@@ -24,4 +24,6 @@ int main()
     {
         std::wofstream fs;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/move.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/move.pass.cpp
index 85fcffee485..3a3e11e9114 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/move.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -46,4 +46,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/path.pass.cpp
index bad7e4f6428..254d696aaf7 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/path.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace fs = std::filesystem;
 
-int main() {
+int main(int, char**) {
   fs::path p = get_temp_file_name();
   {
     static_assert(!std::is_convertible<fs::path, std::ofstream>::value,
@@ -65,4 +65,6 @@ int main() {
     assert(x == 3.25);
   }
   std::remove(p.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/pointer.pass.cpp
index 5e4a18d1ed7..ce23d5e36f4 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/pointer.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -54,4 +54,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/string.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/string.pass.cpp
index 41e739abbe2..c19c278f457 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.cons/string.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -54,4 +54,6 @@ int main()
         assert(x == 3.25);
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/close.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/close.pass.cpp
index 00a70419153..3ea39985ecb 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/close.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/close.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -38,4 +38,6 @@ int main()
         assert(!fs.is_open());
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_path.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_path.pass.cpp
index 857b6c68f84..1b783f6d5e8 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_path.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_path.pass.cpp
@@ -22,7 +22,7 @@
 
 namespace fs = std::filesystem;
 
-int main() {
+int main(int, char**) {
   fs::path p = get_temp_file_name();
   {
     std::ofstream fs;
@@ -58,4 +58,6 @@ int main() {
     assert(c == L'a');
   }
   std::remove(p.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_pointer.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_pointer.pass.cpp
index 689622741d0..5bf58814d26 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_pointer.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -54,4 +54,6 @@ int main()
         assert(c == L'a');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_string.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_string.pass.cpp
index 6a223891a6b..52db618e105 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_string.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/open_string.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -54,4 +54,6 @@ int main()
         assert(c == L'a');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/rdbuf.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/rdbuf.pass.cpp
index 6e8f2fc369e..a7b51fb35d6 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/rdbuf.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     std::string temp = get_temp_file_name();
     {
@@ -32,4 +32,6 @@ int main()
         assert(fb->sputc(L'r') == L'r');
     }
     std::remove(temp.c_str());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ofstream/types.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ofstream/types.pass.cpp
index 1feb4214a75..231807195f1 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ofstream/types.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ofstream/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <fstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_ostream<char>, std::basic_ofstream<char> >::value), "");
     static_assert((std::is_same<std::basic_ofstream<char>::char_type, char>::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::basic_ofstream<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_ofstream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_ofstream<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/file.streams/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/file.streams/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/file.streams/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default.pass.cpp
index 106eb033fd5..1cb88a3510f 100644
--- a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default.pass.cpp
@@ -18,7 +18,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   // Default
   {
@@ -27,4 +27,6 @@ int main() {
     directory_entry e;
     assert(e.path() == path());
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default_const.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default_const.pass.cpp
index 8562312432f..0f681531a09 100644
--- a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default_const.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.cons/default_const.pass.cpp
@@ -19,7 +19,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   // Default
   {
@@ -28,4 +28,6 @@ int main() {
     const directory_entry e;
     assert(e.path() == path());
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/comparisons.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/comparisons.pass.cpp
index 10e8c63b6d0..12158349ef8 100644
--- a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/comparisons.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/comparisons.pass.cpp
@@ -74,7 +74,9 @@ void test_comparisons_simple() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_comparison_signatures();
   test_comparisons_simple();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/path.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/path.pass.cpp
index 185b0ef4a24..28bd2752ec0 100644
--- a/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/path.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_entry/directory_entry.obs/path.pass.cpp
@@ -81,7 +81,9 @@ void test_path_conversion() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_path_method();
   test_path_conversion();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_iterator/directory_iterator.members/default_ctor.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_iterator/directory_iterator.members/default_ctor.pass.cpp
index c318bdb33f6..9f60ec28674 100644
--- a/libcxx/test/std/input.output/filesystems/class.directory_iterator/directory_iterator.members/default_ctor.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_iterator/directory_iterator.members/default_ctor.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
     {
         static_assert(std::is_nothrow_default_constructible<fs::directory_iterator>::value, "");
     }
@@ -31,4 +31,6 @@ int main() {
         const fs::directory_iterator d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_iterator/types.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_iterator/types.pass.cpp
index bac6939035c..3932be0216b 100644
--- a/libcxx/test/std/input.output/filesystems/class.directory_iterator/types.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_iterator/types.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
     using namespace fs;
     using D = directory_iterator;
     ASSERT_SAME_TYPE(D::value_type, directory_entry);
@@ -33,4 +33,6 @@ int main() {
     ASSERT_SAME_TYPE(D::pointer, const directory_entry*);
     ASSERT_SAME_TYPE(D::reference, const directory_entry&);
     ASSERT_SAME_TYPE(D::iterator_category, std::input_iterator_tag);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.file_status/file_status.cons.pass.cpp b/libcxx/test/std/input.output/filesystems/class.file_status/file_status.cons.pass.cpp
index 53c619bd8e9..74fdaaf2084 100644
--- a/libcxx/test/std/input.output/filesystems/class.file_status/file_status.cons.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.file_status/file_status.cons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_convertible.hpp"
 
 
-int main() {
+int main(int, char**) {
  using namespace fs;
   // Default ctor
   {
@@ -56,4 +56,6 @@ int main() {
     assert(f.type()  == file_type::regular);
     assert(f.permissions() == perms::owner_read);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.file_status/file_status.mods.pass.cpp b/libcxx/test/std/input.output/filesystems/class.file_status/file_status.mods.pass.cpp
index 38573beaca8..0ee9f709ba4 100644
--- a/libcxx/test/std/input.output/filesystems/class.file_status/file_status.mods.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.file_status/file_status.mods.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
 
   file_status st;
@@ -45,4 +45,6 @@ int main() {
     st.permissions(perms::owner_read);
     assert(st.permissions() == perms::owner_read);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.file_status/file_status.obs.pass.cpp b/libcxx/test/std/input.output/filesystems/class.file_status/file_status.obs.pass.cpp
index 676ceea8dcc..ec4863139f4 100644
--- a/libcxx/test/std/input.output/filesystems/class.file_status/file_status.obs.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.file_status/file_status.obs.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
 
   const file_status st(file_type::regular, perms::owner_read);
@@ -41,4 +41,6 @@ int main() {
                  "operation must return perms");
     assert(st.permissions() == perms::owner_read);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.filesystem_error/filesystem_error.members.pass.cpp b/libcxx/test/std/input.output/filesystems/class.filesystem_error/filesystem_error.members.pass.cpp
index 075a4137d3a..d9d1a03332d 100644
--- a/libcxx/test/std/input.output/filesystems/class.filesystem_error/filesystem_error.members.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.filesystem_error/filesystem_error.members.pass.cpp
@@ -94,8 +94,10 @@ void test_signatures()
   }
 }
 
-int main() {
+int main(int, char**) {
   static_assert(std::is_base_of<std::system_error, fs::filesystem_error>::value, "");
   test_constructors();
   test_signatures();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.itr/iterator.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.itr/iterator.pass.cpp
index de1e413be24..558206d7082 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.itr/iterator.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.itr/iterator.pass.cpp
@@ -97,8 +97,10 @@ void checkBeginEndBasic() {
 
 }
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   checkIteratorConcepts();
   checkBeginEndBasic(); // See path.decompose.pass.cpp for more tests.
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp
index fb74c8e1946..2f468e59554 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp
@@ -311,7 +311,7 @@ void test_sfinae()
   }
 }
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   for (auto const & TC : Cases) {
@@ -335,4 +335,6 @@ int main()
     doAppendSourceAllocTest<wchar_t>(TC);
   }
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/braced_init.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/braced_init.pass.cpp
index eb45c0981d4..aff89f27bd3 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/braced_init.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/braced_init.pass.cpp
@@ -22,9 +22,11 @@
 #include "count_new.hpp"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   path p("abc");
   p = {};
   assert(p.native() == "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/copy.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/copy.pass.cpp
index 04b8f63cbdd..9265c70f6f4 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/copy.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/copy.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   static_assert(std::is_copy_assignable<path>::value, "");
   static_assert(!std::is_nothrow_copy_assignable<path>::value, "should not be noexcept");
@@ -32,4 +32,6 @@ int main() {
   assert(p.native() == s);
   assert(p2.native() == s);
   assert(&pref == &p2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/move.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/move.pass.cpp
index 12422c68e42..5e5fb1e0e06 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/move.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/move.pass.cpp
@@ -22,7 +22,7 @@
 #include "count_new.hpp"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   static_assert(std::is_nothrow_move_assignable<path>::value, "");
   assert(globalMemCounter.checkOutstandingNewEq(0));
@@ -38,4 +38,6 @@ int main() {
     assert(p.native() != s); // Testing moved from state
     assert(&pref == &p2);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp
index edc0b263844..9c23e3b3ebf 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp
@@ -228,7 +228,7 @@ void RunStringMoveTest(const char* Expect) {
   }
 }
 
-int main() {
+int main(int, char**) {
   for (auto const& MS : PathList) {
     RunTestCase<char>(MS);
     RunTestCase<wchar_t>(MS);
@@ -237,4 +237,6 @@ int main() {
     RunStringMoveTest(MS);
   }
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp
index 41efb7513fa..165e62fe4fe 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp
@@ -184,7 +184,9 @@ void test_compare_elements() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_compare_basic();
   test_compare_elements();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp
index 842d70543a0..b074e831e15 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp
@@ -325,7 +325,7 @@ void test_sfinae() {
   }
 }
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   for (auto const & TC : Cases) {
@@ -384,4 +384,6 @@ int main()
     doConcatECharTest<char32_t>(TC);
   }
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/copy.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/copy.pass.cpp
index 789789779a4..1490c0b9fed 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/copy.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/copy.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   static_assert(std::is_copy_constructible<path>::value, "");
   static_assert(!std::is_nothrow_copy_constructible<path>::value, "should not be noexcept");
@@ -30,4 +30,6 @@ int main() {
   path p2(p);
   assert(p.native() == s);
   assert(p2.native() == s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/default.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/default.pass.cpp
index 203c0e5ee61..b31728da1f9 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/default.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/default.pass.cpp
@@ -21,9 +21,11 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   static_assert(std::is_nothrow_default_constructible<path>::value, "");
   const path p;
   assert(p.empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/move.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/move.pass.cpp
index 4382de14170..494a77c3c86 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/move.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/move.pass.cpp
@@ -22,7 +22,7 @@
 #include "count_new.hpp"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   static_assert(std::is_nothrow_move_constructible<path>::value, "");
   assert(globalMemCounter.checkOutstandingNewEq(0));
@@ -36,4 +36,6 @@ int main() {
     assert(p2.native() == s);
     assert(p.native() != s); // Testing moved from state
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/source.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/source.pass.cpp
index b10d3aa88cd..bcb9986cec9 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/source.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.construct/source.pass.cpp
@@ -117,7 +117,7 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   for (auto const& MS : PathList) {
     RunTestCase<char>(MS);
     RunTestCase<wchar_t>(MS);
@@ -125,4 +125,6 @@ int main() {
     RunTestCase<char32_t>(MS);
   }
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/empty.fail.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/empty.fail.cpp
index 481ffcde60f..5248f67515a 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/empty.fail.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     fs::path c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/path.decompose.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/path.decompose.pass.cpp
index aa511cdf014..be9cefb76a8 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/path.decompose.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.decompose/path.decompose.pass.cpp
@@ -208,8 +208,10 @@ void decompFilenameTest()
   }
 }
 
-int main()
+int main(int, char**)
 {
   decompPathTest();
   decompFilenameTest();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_normal.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_normal.pass.cpp
index 4d295eec5e6..f1e616542e9 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_normal.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_normal.pass.cpp
@@ -26,7 +26,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main() {
+int main(int, char**) {
   // clang-format off
   struct {
     std::string input;
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp
index 96fa1597b02..7e31956ee50 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp
@@ -27,7 +27,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main() {
+int main(int, char**) {
   // clang-format off
   struct {
     std::string input;
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp
index 7cb81ca0008..707a7010ffb 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp
@@ -33,7 +33,7 @@ MultiStringType longString = MKSTR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQR
 // generic_string<C, T, A> forwards to string<C, T, A>. Tests for
 // string<C, T, A>() are in "path.native.op/string_alloc.pass.cpp".
 // generic_string is minimally tested here.
-int main()
+int main(int, char**)
 {
   using namespace fs;
   using CharT = wchar_t;
@@ -51,4 +51,6 @@ int main()
     assert(Alloc::alloc_count > 0);
     assert(Alloc::outstanding_alloc() == 1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/named_overloads.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/named_overloads.pass.cpp
index 2e33769cdb3..04ae673ac48 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/named_overloads.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.generic.obs/named_overloads.pass.cpp
@@ -31,7 +31,7 @@
 
 MultiStringType longString = MKSTR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/123456789/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   auto const& MS = longString;
@@ -57,4 +57,6 @@ int main()
     std::u32string s = p.generic_u32string();
     assert(s == (const char32_t*)MS);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/clear.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/clear.pass.cpp
index a224dddfa97..01538539faf 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/clear.pass.cpp
@@ -24,7 +24,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   {
     path p;
@@ -40,4 +40,6 @@ int main() {
     p2.clear();
     assert(p2.empty());
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/make_preferred.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/make_preferred.pass.cpp
index 43393aba5da..4530ef87554 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/make_preferred.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/make_preferred.pass.cpp
@@ -39,7 +39,7 @@ const MakePreferredTestcase TestCases[] =
     , {"\\foo\\/bar\\/baz\\"}
   };
 
-int main()
+int main(int, char**)
 {
   // This operation is an identity operation on linux.
   using namespace fs;
@@ -50,4 +50,6 @@ int main()
     assert(p.native() == TC.value);
     assert(&Ref == &p);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/remove_filename.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/remove_filename.pass.cpp
index 42191379dbb..7cb562c227f 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/remove_filename.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/remove_filename.pass.cpp
@@ -57,7 +57,7 @@ const RemoveFilenameTestcase TestCases[] =
     , {"bar/../baz/./file.txt", "bar/../baz/./"}
   };
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   for (auto const & TC : TestCases) {
@@ -69,4 +69,6 @@ int main()
     assert(&Ref == &p);
     assert(!p.has_filename());
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_extension.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_extension.pass.cpp
index 70040c48ae5..6fec420baa0 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_extension.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_extension.pass.cpp
@@ -51,7 +51,7 @@ const ReplaceExtensionTestcase NoArgCases[] =
     , {"foo..cpp", "foo.", ""}
 };
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   for (auto const & TC : TestCases) {
@@ -68,4 +68,6 @@ int main()
     assert(p == TC.expect);
     assert(&Ref == &p);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_filename.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_filename.pass.cpp
index 3635352210b..8142e790731 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_filename.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/replace_filename.pass.cpp
@@ -47,7 +47,7 @@ const ReplaceFilenameTestcase TestCases[] =
     , {"/foo\\baz/bong", "/foo\\baz/bar", "bar"}
   };
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   for (auto const & TC : TestCases) {
@@ -67,4 +67,6 @@ int main()
       ASSERT_EQ(p, p2);
     }
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/swap.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/swap.pass.cpp
index ac623dbfcc5..2e9dac5e438 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/swap.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.modifiers/swap.pass.cpp
@@ -41,7 +41,7 @@ const SwapTestcase TestCases[] =
 #undef LONG_STR1
 #undef LONG_STR2
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   {
@@ -76,4 +76,6 @@ int main()
     }
     assert(p1 == Val);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/c_str.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/c_str.pass.cpp
index 3f2fac696da..8b35ee8c80a 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/c_str.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/c_str.pass.cpp
@@ -23,7 +23,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   const char* const value = "hello world";
@@ -38,4 +38,6 @@ int main()
     assert(p.c_str() == str_value);
     assert(p.native().c_str() == p.c_str());
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/named_overloads.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/named_overloads.pass.cpp
index 0d747b18895..c06de9795e3 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/named_overloads.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/named_overloads.pass.cpp
@@ -32,7 +32,7 @@
 
 MultiStringType longString = MKSTR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/123456789/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   auto const& MS = longString;
@@ -58,4 +58,6 @@ int main()
     std::u32string s = p.u32string();
     assert(s == (const char32_t*)MS);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/native.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/native.pass.cpp
index 14feaf13e8e..3b88b5d6c64 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/native.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/native.pass.cpp
@@ -22,7 +22,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   const char* const value = "hello world";
@@ -35,4 +35,6 @@ int main()
     path p(value);
     assert(p.native() == value);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/operator_string.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/operator_string.pass.cpp
index 53fdcc16034..9f0069051fd 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/operator_string.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/operator_string.pass.cpp
@@ -23,7 +23,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   using string_type = path::string_type;
@@ -42,4 +42,6 @@ int main()
     assert(s == value);
     assert(p == value);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp
index 86453f8d0b9..4ace380b873 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp
@@ -116,7 +116,7 @@ void doLongStringTest(MultiStringType const& MS) {
   /////////////////////////////////////////////////////////////////////////////
 }
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   {
@@ -133,4 +133,6 @@ int main()
     doLongStringTest<char16_t>(S);
     doLongStringTest<char32_t>(S);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.query/tested_in_path_decompose.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.query/tested_in_path_decompose.pass.cpp
index d825788506b..32c37e7f7a5 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.query/tested_in_path_decompose.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.query/tested_in_path_decompose.pass.cpp
@@ -28,4 +28,6 @@
 // bool is_relative() const;
 
 // tested in path.decompose
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp
index 7b5082c8f8d..bcc4758f45f 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp
@@ -20,7 +20,9 @@ struct ConvToPath {
   }
 };
 
-int main() {
+int main(int, char**) {
   ConvToPath LHS, RHS;
   (void)(LHS / RHS); // expected-error {{invalid operands to binary expression}}
+
+  return 0;
 }
\ No newline at end of file
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp
index 2c7042e9b7b..67af37686df 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp
@@ -20,7 +20,7 @@
 #include "filesystem_test_helper.hpp"
 
 // This is mainly tested via the member append functions.
-int main()
+int main(int, char**)
 {
   using namespace fs;
   path p1("abc");
@@ -30,4 +30,6 @@ int main()
 
   path p4 = p1 / "def";
   assert(p4 == "abc/def");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp
index 287e315237b..8f1732186d8 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp
@@ -21,7 +21,7 @@ struct ConvToPath {
   }
 };
 
-int main() {
+int main(int, char**) {
   ConvToPath LHS, RHS;
   (void)(LHS == RHS); // expected-error {{invalid operands to binary expression}}
   (void)(LHS != RHS); // expected-error {{invalid operands to binary expression}}
@@ -29,4 +29,6 @@ int main() {
   (void)(LHS <= RHS); // expected-error {{invalid operands to binary expression}}
   (void)(LHS > RHS); // expected-error {{invalid operands to binary expression}}
   (void)(LHS >= RHS); // expected-error {{invalid operands to binary expression}}
+
+  return 0;
 }
\ No newline at end of file
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops_tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops_tested_elsewhere.pass.cpp
index 3728db5f224..c61a5a0254c 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops_tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops_tested_elsewhere.pass.cpp
@@ -10,4 +10,6 @@
 
 // The comparison operators are tested as part of [path.compare]
 // in class.path/path.members/path.compare.pass.cpp
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/hash_value_tested_elswhere.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/hash_value_tested_elswhere.pass.cpp
index 6cf310be88b..49d28daf98f 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/hash_value_tested_elswhere.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/hash_value_tested_elswhere.pass.cpp
@@ -10,4 +10,6 @@
 
 // The "hash_value" function is tested as part of [path.compare]
 // in class.path/path.members/path.compare.pass.cpp
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp
index 54d0799d92a..557849ca8e6 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp
@@ -25,7 +25,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main()
+int main(int, char**)
 {
   using namespace fs;
   const char* In1 = "abcd/efg";
@@ -48,4 +48,6 @@ int main()
     path p = fs::u8path(In3, In3End);
     assert(p == In1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.pass.cpp
index 375e45da8e6..31eea925a5d 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.pass.cpp
@@ -88,10 +88,12 @@ void test_LWG2989() {
   static_assert(!is_istreamable<decltype(std::wcin), std::string>::value, "");
 }
 
-int main() {
+int main(int, char**) {
   doIOTest<char>();
   doIOTest<wchar_t>();
   //doIOTest<char16_t>();
   //doIOTest<char32_t>();
   test_LWG2989();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.unicode_bug.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.unicode_bug.pass.cpp
index 2072a9450fb..c5bb6bf120f 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.unicode_bug.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.io.unicode_bug.pass.cpp
@@ -62,7 +62,9 @@ void doIOTest() {
 }
 
 
-int main() {
+int main(int, char**) {
   doIOTest<char16_t>();
   doIOTest<char32_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/swap.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/swap.pass.cpp
index 66d854f00b2..51bb03e9f7c 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/swap.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/swap.pass.cpp
@@ -22,7 +22,7 @@
 
 
 // NOTE: this is tested in path.members/path.modifiers via the member swap.
-int main()
+int main(int, char**)
 {
   using namespace fs;
   const char* value1 = "foo/bar/baz";
@@ -45,4 +45,6 @@ int main()
     assert(p1.native() == value1);
     assert(p2.native() == value2);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/synop.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/synop.pass.cpp
index 9b91651e08f..8aa186e32ae 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/synop.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/synop.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 
 
-int main() {
+int main(int, char**) {
   using namespace fs;
   ASSERT_SAME_TYPE(path::value_type, char);
   ASSERT_SAME_TYPE(path::string_type, std::basic_string<path::value_type>);
@@ -34,4 +34,6 @@ int main() {
     const char* dummy = &path::preferred_separator;
     ((void)dummy);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.copy_options.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.copy_options.pass.cpp
index 25f63a92b33..b949960df11 100644
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.copy_options.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.copy_options.pass.cpp
@@ -22,7 +22,7 @@
 
 constexpr fs::copy_options ME(int val) { return static_cast<fs::copy_options>(val); }
 
-int main() {
+int main(int, char**) {
   typedef fs::copy_options E;
   static_assert(std::is_enum<E>::value, "");
 
@@ -59,4 +59,6 @@ int main() {
           E::create_symlinks     == ME(128) &&
           E::create_hard_links   == ME(256),
         "Expected enumeration values do not match");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.directory_options.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.directory_options.pass.cpp
index 54574f720f5..43b0945978e 100644
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.directory_options.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.directory_options.pass.cpp
@@ -23,7 +23,7 @@
 
 constexpr fs::directory_options ME(int val) { return static_cast<fs::directory_options>(val); }
 
-int main() {
+int main(int, char**) {
   typedef fs::directory_options E;
   static_assert(std::is_enum<E>::value, "");
 
@@ -41,4 +41,6 @@ int main() {
         E::skip_permission_denied   == ME(2),
         "Expected enumeration values do not match");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.file_type.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.file_type.pass.cpp
index d2162d08383..c1f16079a5d 100644
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.file_type.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.file_type.pass.cpp
@@ -21,7 +21,7 @@
 
 constexpr fs::file_type ME(int val) { return static_cast<fs::file_type>(val); }
 
-int main() {
+int main(int, char**) {
   typedef fs::file_type E;
   static_assert(std::is_enum<E>::value, "");
 
@@ -43,4 +43,6 @@ int main() {
           E::socket == ME(7) &&
           E::unknown == ME(8),
         "Expected enumeration values do not match");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.path.format.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.path.format.pass.cpp
index fc11e8a9c1f..d60225d4ff6 100644
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.path.format.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.path.format.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   typedef fs::path::format E;
   static_assert(std::is_enum<E>::value, "");
 
@@ -34,4 +34,6 @@ int main() {
           E::auto_format   != E::generic_format &&
           E::native_format != E::generic_format,
         "Expected enumeration values are not unique");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp
index 117c35875e0..1fd353d041f 100644
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp
@@ -25,7 +25,7 @@ constexpr fs::perm_options ME(int val) {
   return static_cast<fs::perm_options>(val);
 }
 
-int main() {
+int main(int, char**) {
   typedef fs::perm_options E;
   static_assert(std::is_enum<E>::value, "");
 
@@ -44,4 +44,6 @@ int main() {
         E::remove   == ME(4) &&
         E::nofollow == ME(8),
         "Expected enumeration values do not match");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.perms.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.perms.pass.cpp
index e043c87e5c1..93b5278fdd4 100644
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.perms.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.perms.pass.cpp
@@ -23,7 +23,7 @@
 
 constexpr fs::perms ME(int val) { return static_cast<fs::perms>(val); }
 
-int main() {
+int main(int, char**) {
   typedef fs::perms E;
   static_assert(std::is_enum<E>::value, "");
 
@@ -60,4 +60,6 @@ int main() {
         E::mask         == ME(07777) &&
         E::unknown      == ME(0xFFFF),
         "Expected enumeration values do not match");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.error.report/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.error.report/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/filesystems/fs.error.report/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.error.report/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.filesystem.synopsis/file_time_type.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.filesystem.synopsis/file_time_type.pass.cpp
index 6606c9a27cf..e88ef1d12c4 100644
--- a/libcxx/test/std/input.output/filesystems/fs.filesystem.synopsis/file_time_type.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.filesystem.synopsis/file_time_type.pass.cpp
@@ -39,7 +39,9 @@ void test_time_point_resolution_and_range() {
   ASSERT_SAME_TYPE(Period, std::nano);
 }
 
-int main() {
+int main(int, char**) {
   test_trivial_clock();
   test_time_point_resolution_and_range();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.weakly_canonical/weakly_canonical.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.weakly_canonical/weakly_canonical.pass.cpp
index c655490acf8..94a8e13bc08 100644
--- a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.weakly_canonical/weakly_canonical.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.weakly_canonical/weakly_canonical.pass.cpp
@@ -25,7 +25,7 @@
 #include "filesystem_test_helper.hpp"
 
 
-int main() {
+int main(int, char**) {
   // clang-format off
   struct {
     std::string input;
diff --git a/libcxx/test/std/input.output/filesystems/fs.req.macros/feature_macro.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.req.macros/feature_macro.pass.cpp
index aa1933cc6b1..dad1868bee3 100644
--- a/libcxx/test/std/input.output/filesystems/fs.req.macros/feature_macro.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.req.macros/feature_macro.pass.cpp
@@ -25,4 +25,6 @@
 #endif
 #endif
 
-int main() { }
+int main(int, char**) { 
+  return 0;
+}
diff --git a/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.fail.cpp b/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.fail.cpp
index e3030995de1..641621e7338 100644
--- a/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.fail.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.fail.cpp
@@ -23,6 +23,8 @@ using namespace std::filesystem;
 // expected-error@-5 {{expected namespace name}}
 #endif
 
-int main() {
+int main(int, char**) {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.pass.cpp
index 96ba646ffbe..65864336901 100644
--- a/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.req.namespace/namespace.pass.cpp
@@ -17,9 +17,11 @@
 
 using namespace std::filesystem;
 
-int main() {
+int main(int, char**) {
   static_assert(std::is_same<
           path,
           std::filesystem::path
       >::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/input.output.general/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/input.output.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/input.output.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/input.output.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/ext.manip/get_money.pass.cpp b/libcxx/test/std/input.output/iostream.format/ext.manip/get_money.pass.cpp
index 0a68da1c44f..cb1f2c68ee5 100644
--- a/libcxx/test/std/input.output/iostream.format/ext.manip/get_money.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/ext.manip/get_money.pass.cpp
@@ -38,7 +38,7 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("  -$1,234,567.89");
@@ -72,4 +72,6 @@ int main()
         is >> std::get_money(x, true);
         assert(x == -123456789);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/ext.manip/get_time.pass.cpp b/libcxx/test/std/input.output/iostream.format/ext.manip/get_time.pass.cpp
index 05ed05c39f7..ebf62c08e72 100644
--- a/libcxx/test/std/input.output/iostream.format/ext.manip/get_time.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/ext.manip/get_time.pass.cpp
@@ -38,7 +38,7 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("  Sat Dec 31 23:55:59 2061");
@@ -72,4 +72,6 @@ int main()
         assert(is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp b/libcxx/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp
index 0dffdfb5fe1..d924d77bc7d 100644
--- a/libcxx/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/ext.manip/put_money.pass.cpp
@@ -50,7 +50,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -88,4 +88,6 @@ int main()
         os << std::put_money(x, true);
         assert(sb.str() == L"-USD 1,234,567.89");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp b/libcxx/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp
index 7dcbcf48838..faa99e06343 100644
--- a/libcxx/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/ext.manip/put_time.pass.cpp
@@ -50,7 +50,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -83,4 +83,6 @@ int main()
         os << std::put_time(&t, L"%a %b %d %H:%M:%S %Y");
         assert(sb.str() == L"Sat Dec 31 23:55:59 2061");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/member_swap.pass.cpp
index b9505c76ed0..44b394b8fb0 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/member_swap.pass.cpp
@@ -33,7 +33,7 @@ struct test_iostream
     void swap(test_iostream& s) {base::swap(s);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb1;
@@ -81,4 +81,6 @@ int main()
         assert(is2.precision() == 6);
         assert(is2.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/move_assign.pass.cpp
index f53411270b5..c7918ec8d73 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.assign/move_assign.pass.cpp
@@ -38,7 +38,7 @@ struct test_iostream
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb1;
@@ -86,4 +86,6 @@ int main()
         assert(is2.precision() == 6);
         assert(is2.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/move.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/move.pass.cpp
index 2dc91457ce7..611a7a670d2 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/move.pass.cpp
@@ -38,7 +38,7 @@ struct test_iostream
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -72,4 +72,6 @@ int main()
         assert(is.precision() == 6);
         assert(is.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/streambuf.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/streambuf.pass.cpp
index bf6fe65badc..c12abc0e2dc 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.cons/streambuf.pass.cpp
@@ -23,7 +23,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -51,4 +51,6 @@ int main()
         assert(is.getloc().name() == "C");
         assert(is.gcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.dest/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.dest/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.dest/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/iostream.dest/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/types.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/types.pass.cpp
index ef7dcd24e3b..46d7a16aac7 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/types.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/iostreamclass/types.pass.cpp
@@ -24,7 +24,7 @@
 #include <istream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_istream<char>, std::basic_iostream<char> >::value), "");
     static_assert((std::is_base_of<std::basic_ostream<char>, std::basic_iostream<char> >::value), "");
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<std::basic_iostream<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_iostream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_iostream<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/bool.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/bool.pass.cpp
index 570aeaa393c..799ec5eaeb5 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/bool.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/bool.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/double.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/double.pass.cpp
index 6a285556d81..9f9872d9ef8 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/double.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/double.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/float.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/float.pass.cpp
index da93a3bafc2..c2b937a89cf 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/float.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/float.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/int.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/int.pass.cpp
index f683bee45da..702287be79e 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/int.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/int.pass.cpp
@@ -41,7 +41,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -76,4 +76,6 @@ int main()
         assert(!is.eof());
         assert( is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long.pass.cpp
index 0c8eee50d75..9f9118cbcdc 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_double.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_double.pass.cpp
index 2fff174cbcc..bdd30190a5b 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_double.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_double.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_long.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_long.pass.cpp
index 6529ad333f5..1612468f4d7 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/long_long.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/pointer.pass.cpp
index 3c8a0783fa4..0893d8cdec2 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/pointer.pass.cpp
@@ -44,7 +44,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -97,4 +97,6 @@ int main()
         assert( is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/short.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/short.pass.cpp
index bc28ec29ba9..a0d96c3983f 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/short.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/short.pass.cpp
@@ -41,7 +41,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -76,4 +76,6 @@ int main()
         assert(!is.eof());
         assert( is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_int.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_int.pass.cpp
index 8bbb636e6e8..578cfcf0cc4 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_int.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_int.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long.pass.cpp
index 5635339a816..f1c150d7920 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long_long.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long_long.pass.cpp
index 402d3eab0ad..068d31ac8fb 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long_long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_long_long.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_short.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_short.pass.cpp
index cedd6a6c8af..9906bbeac8d 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_short.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.arithmetic/unsigned_short.pass.cpp
@@ -40,7 +40,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(!is.eof());
         assert(!is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.reqmts/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.reqmts/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.reqmts/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream.formatted.reqmts/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/basic_ios.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/basic_ios.pass.cpp
index fadc70943db..704c4997d52 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/basic_ios.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/basic_ios.pass.cpp
@@ -27,11 +27,13 @@ f(std::basic_ios<CharT>& is)
     return is;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
         is >> f;
         assert(f_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/chart.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/chart.pass.cpp
index 51e0aab1a42..cbb606cdcff 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/chart.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/chart.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("          ");
@@ -83,4 +83,6 @@ int main()
         assert(!is.fail());
         assert(c == L'c');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/ios_base.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/ios_base.pass.cpp
index 31023cca89f..ec25dc5a7e0 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/ios_base.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/ios_base.pass.cpp
@@ -25,11 +25,13 @@ f(std::ios_base& is)
     return is;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
         is >> f;
         assert(f_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/istream.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/istream.pass.cpp
index 36ea25dafc8..f3829c25ac4 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/istream.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/istream.pass.cpp
@@ -27,11 +27,13 @@ f(std::basic_istream<CharT>& is)
     return is;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((std::streambuf*)0);
         is >> f;
         assert(f_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char.pass.cpp
index 293cd8b459a..bd06de6a07b 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("          ");
@@ -66,4 +66,6 @@ int main()
         assert(!is.fail());
         assert(c == 'c');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char_pointer.pass.cpp
index 55db22bce7e..d5128339a71 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/signed_char_pointer.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("   abcdefghijk    ");
@@ -103,4 +103,6 @@ int main()
         assert(std::string((char*)s) == "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp
index dbc6e2398df..9feb826906f 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/streambuf.pass.cpp
@@ -55,7 +55,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("testing...");
@@ -65,4 +65,6 @@ int main()
         assert(sb2.str() == "testing...");
         assert(is.gcount() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char.pass.cpp
index 17aff9fd8de..3eceaaeb63f 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("          ");
@@ -66,4 +66,6 @@ int main()
         assert(!is.fail());
         assert(c == 'c');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char_pointer.pass.cpp
index 1873d70fbb2..14b2993148d 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/unsigned_char_pointer.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("   abcdefghijk    ");
@@ -103,4 +103,6 @@ int main()
         assert(std::string((char*)s) == "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/wchar_t_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/wchar_t_pointer.pass.cpp
index cc06149b36e..f0a9e0710fb 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/wchar_t_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/wchar_t_pointer.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("   abcdefghijk    ");
@@ -114,4 +114,6 @@ int main()
         assert(std::string(s) == "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.manip/ws.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.manip/ws.pass.cpp
index a1ab81a9553..6786ebf4ca0 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.manip/ws.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.manip/ws.pass.cpp
@@ -39,7 +39,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("   123");
@@ -75,4 +75,6 @@ int main()
         assert(is.eof());
         assert(is.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.rvalue/rvalue.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.rvalue/rvalue.pass.cpp
index cd46b14fdde..8d0af734703 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.rvalue/rvalue.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.rvalue/rvalue.pass.cpp
@@ -47,7 +47,7 @@ struct A{};
 bool called = false;
 void operator>>(std::istream&, A&&){ called = true; }
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("   123");
@@ -68,4 +68,6 @@ int main()
         assert(&out == &ss);
         assert(called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get.pass.cpp
index b73a2fe72d8..40a04174133 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("          ");
@@ -96,4 +96,6 @@ int main()
         assert(c == L'c');
         assert(is.gcount() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_chart.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_chart.pass.cpp
index 86189b26049..ae31c9be06d 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_chart.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_chart.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("          ");
@@ -99,4 +99,6 @@ int main()
         assert(c == L'c');
         assert(is.gcount() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size.pass.cpp
index ca2827aa0bd..149392cae3f 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size.pass.cpp
@@ -48,7 +48,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("  \n    \n ");
@@ -158,4 +158,6 @@ int main()
         assert(is.gcount() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size_chart.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size_chart.pass.cpp
index efaf168d6d6..e7c96d6a266 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size_chart.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_pointer_size_chart.pass.cpp
@@ -48,7 +48,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("  *    * ");
@@ -158,4 +158,6 @@ int main()
         assert(is.gcount() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp
index 35495ef953b..dda59d7ff50 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf.pass.cpp
@@ -52,7 +52,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("testing\n...");
@@ -84,4 +84,6 @@ int main()
         assert(!is.fail());
         assert(is.gcount() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp
index 514cd2e7f6c..a1e46c2336c 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/get_streambuf_chart.pass.cpp
@@ -53,7 +53,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("testing*...");
@@ -85,4 +85,6 @@ int main()
         assert(!is.fail());
         assert(is.gcount() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size.pass.cpp
index 5fa822cd187..9c91053ebdb 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size.pass.cpp
@@ -48,7 +48,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("  \n    \n ");
@@ -142,4 +142,6 @@ int main()
         assert(is.gcount() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size_chart.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size_chart.pass.cpp
index 1cd19c0e1dd..bee1976e95e 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size_chart.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/getline_pointer_size_chart.pass.cpp
@@ -48,7 +48,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("  *    * ");
@@ -142,4 +142,6 @@ int main()
         assert(is.gcount() == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore.pass.cpp
index 99f35aac407..7f6348b01a4 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore.pass.cpp
@@ -38,7 +38,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 1\n2345\n6");
@@ -72,4 +72,6 @@ int main()
         assert(!is.fail());
         assert(is.gcount() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore_0xff.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore_0xff.pass.cpp
index f2f895d9ce6..acf90e56086 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore_0xff.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore_0xff.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int bad=-1;
     std::ostringstream os;
@@ -30,4 +30,6 @@ int main()
     is.ignore(ignoreLen);
     std::istringstream::pos_type b=is.tellg();
     assert((b-a)==ignoreLen);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/peek.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/peek.pass.cpp
index 99b2b69341b..17943463e90 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/peek.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/peek.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 1\n2345\n6");
@@ -65,4 +65,6 @@ int main()
         assert(!is.fail());
         assert(is.gcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/putback.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/putback.pass.cpp
index 2088e4d14cb..4ca3a8c0edb 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/putback.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/putback.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -85,4 +85,6 @@ int main()
         assert(is.bad());
         assert(is.gcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/read.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/read.pass.cpp
index 962aa8c0386..9296e0bfb2e 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/read.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/read.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -77,4 +77,6 @@ int main()
         assert( is.fail());
         assert(is.gcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/readsome.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/readsome.pass.cpp
index 5cfd028cc62..f99752cc1a5 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/readsome.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/readsome.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 1234567890");
@@ -81,4 +81,6 @@ int main()
         assert(std::wstring(s, 1) == L"0");
         assert(is.readsome(s, 5) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg.pass.cpp
index b5e1955a7be..c16a6397863 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg.pass.cpp
@@ -44,7 +44,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -71,4 +71,6 @@ int main()
         assert(is.good());
         assert(!is.eof());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg_off.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg_off.pass.cpp
index d7607b62e9d..93a7f1912d9 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg_off.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/seekg_off.pass.cpp
@@ -52,7 +52,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -83,4 +83,6 @@ int main()
         assert(is.good());
         assert(!is.eof());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp
index 10bc991aa0f..43ddd811080 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp
@@ -46,7 +46,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -60,4 +60,6 @@ int main()
         assert(is.sync() == 0);
         assert(sync_called == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/tellg.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/tellg.pass.cpp
index 7f87cada9ac..918685b8693 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/tellg.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/tellg.pass.cpp
@@ -47,7 +47,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -59,4 +59,6 @@ int main()
         std::wistream is(&sb);
         assert(is.tellg() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/unget.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/unget.pass.cpp
index c982f79cb96..ca00af4e3c3 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/unget.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/unget.pass.cpp
@@ -37,7 +37,7 @@ public:
     CharT* egptr() const {return base::egptr();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb(" 123456789");
@@ -77,4 +77,6 @@ int main()
         assert(is.bad());
         assert(is.gcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/member_swap.pass.cpp
index 8e8b16600df..dbb2bb69e36 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/member_swap.pass.cpp
@@ -33,7 +33,7 @@ struct test_istream
     void swap(test_istream& s) {base::swap(s);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb1;
@@ -81,4 +81,6 @@ int main()
         assert(is2.precision() == 6);
         assert(is2.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/move_assign.pass.cpp
index cc418fd4f13..455edbf72ac 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.assign/move_assign.pass.cpp
@@ -38,7 +38,7 @@ struct test_istream
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb1;
@@ -86,4 +86,6 @@ int main()
         assert(is2.precision() == 6);
         assert(is2.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/copy.fail.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/copy.fail.cpp
index c26ad292ba8..017cc67a1d5 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/copy.fail.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/copy.fail.cpp
@@ -48,7 +48,9 @@ struct test_istream
 };
 
 
-int main()
+int main(int, char**)
 {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/move.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/move.pass.cpp
index 7bf3d6619b0..4830d04d48c 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/move.pass.cpp
@@ -36,7 +36,7 @@ struct test_istream
         : base(std::move(s)) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -70,4 +70,6 @@ int main()
         assert(is.precision() == 6);
         assert(is.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/streambuf.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/streambuf.pass.cpp
index 71008f7d096..339489dfb5e 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream.cons/streambuf.pass.cpp
@@ -23,7 +23,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -51,4 +51,6 @@ int main()
         assert(is.getloc().name() == "C");
         assert(is.gcount() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream_sentry/ctor.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream_sentry/ctor.pass.cpp
index 29fed345a54..fdebd66fb76 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream_sentry/ctor.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/istream_sentry/ctor.pass.cpp
@@ -49,7 +49,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::istream is((testbuf<char>*)0);
@@ -124,4 +124,6 @@ int main()
         assert(sync_called == 0);
         assert(sb.gptr() == sb.eback());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/input.streams/istream/types.pass.cpp b/libcxx/test/std/input.output/iostream.format/input.streams/istream/types.pass.cpp
index 07e2f5558fe..a5362d94b8c 100644
--- a/libcxx/test/std/input.output/iostream.format/input.streams/istream/types.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/input.streams/istream/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <istream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_ios<char>, std::basic_istream<char> >::value), "");
     static_assert((std::is_same<std::basic_istream<char>::char_type, char>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<std::basic_istream<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_istream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_istream<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostream.format/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostream.format/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/member_swap.pass.cpp
index f322a8145bd..433d78ead19 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/member_swap.pass.cpp
@@ -33,7 +33,7 @@ struct test_ostream
     void swap(test_ostream& s) {base::swap(s);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb1;
@@ -81,4 +81,6 @@ int main()
         assert(os2.precision() == 6);
         assert(os2.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/move_assign.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/move_assign.pass.cpp
index a121cd8a5b9..4241b02a36d 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.assign/move_assign.pass.cpp
@@ -38,7 +38,7 @@ struct test_ostream
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb1;
@@ -86,4 +86,6 @@ int main()
         assert(os2.precision() == 6);
         assert(os2.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/move.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/move.pass.cpp
index 155889de717..811b7fa8566 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/move.pass.cpp
@@ -38,7 +38,7 @@ struct test_ostream
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -68,4 +68,6 @@ int main()
         assert(os.precision() == 6);
         assert(os.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/streambuf.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/streambuf.pass.cpp
index ea4542be29e..78a3a53c74e 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.cons/streambuf.pass.cpp
@@ -23,7 +23,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -49,4 +49,6 @@ int main()
         assert(os.precision() == 6);
         assert(os.getloc().name() == "C");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.reqmts/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.reqmts/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.reqmts/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.reqmts/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp
index e472c62660d..a0622b36567 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/bool.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -87,4 +87,6 @@ int main()
         os << b;
         assert(sb.str() == "false");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp
index f18d9361ac4..2c83723cbfa 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/double.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "-10.5");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp
index 041195d0e36..851086abe42 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/float.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "-10.5");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp
index 4657c98f9c9..7dae78f9def 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/int.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fffffff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp
index cf0184997b8..8f2ec631c03 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fffffff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp
index cedef612149..b0c9950bd7a 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_double.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "-10.5");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp
index 20b23b80bec..d87096f7213 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/long_long.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fffffffffffffff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minmax_showbase.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minmax_showbase.pass.cpp
index c101b3cfc99..6db1b55cca7 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minmax_showbase.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minmax_showbase.pass.cpp
@@ -45,7 +45,7 @@ static void test(std::ios_base::fmtflags fmt, const char *expected)
     assert(ss.str() == expected);
 }
 
-int main()
+int main(int, char**)
 {
     const std::ios_base::fmtflags o = std::ios_base::oct;
     const std::ios_base::fmtflags d = std::ios_base::dec;
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minus1.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minus1.pass.cpp
index 7d51a4ddd04..c2b188a15f9 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minus1.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minus1.pass.cpp
@@ -58,7 +58,7 @@ void test_hex(const char *expected)
     assert(str == expected);
 }
 
-int main()
+int main(int, char**)
 {
 
     test_octal<uint16_t>(                "177777");
@@ -110,4 +110,6 @@ int main()
         test_hex<unsigned long long>("FFFFFFFFFFFFFFFF");
         test_hex<         long long>("FFFFFFFFFFFFFFFF");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp
index 837efd6f38a..f400f33544b 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/pointer.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -87,4 +87,6 @@ int main()
         os << n;
         assert(os.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp
index 8e022edad01..c45d5797b5e 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/short.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp
index 2d6b0be0274..c24381923d1 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_int.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp
index 636c87146fe..03b63964302 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fffffff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp
index 44313251e10..3c12f148898 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_long_long.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fffffffffffffff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp
index 16b33f3a94e..6cc4c71a094 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/unsigned_short.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -79,4 +79,6 @@ int main()
         os << n;
         assert(sb.str() == "fff6");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp
index cb7f0d62f47..127c0c7dc5b 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::wostream os((std::wstreambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == L"a    ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp
index a07edba5d9f..85edde06d4f 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/CharT_pointer.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::wostream os((std::wstreambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == L"123  ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp
index 6e926d10fb0..5532a68650b 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == "a    ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp
index 23874768fd0..f6e2445faeb 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_pointer.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == "123  ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp
index f5647e1a924..f12478e5384 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::wostream os((std::wstreambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == L"a    ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp
index ff4e85eb90f..1b11d8550ae 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/char_to_wide_pointer.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::wostream os((std::wstreambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == L"123  ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp
index ab3e9b580b8..26f295ec2d0 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == "a    ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp
index 36b9586b812..83143521bc5 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/signed_char_pointer.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == "123  ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp
index 95609a2642b..e45281f866f 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == "a    ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp
index ef7e6166e9d..55b429b2dc4 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.character/unsigned_char_pointer.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -84,4 +84,6 @@ int main()
         assert(sb.str() == "123  ");
         assert(os.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp
index 1d205625081..921311f99ce 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp
@@ -57,7 +57,7 @@ f(std::basic_ios<CharT>& os)
     return os;
 }
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -66,4 +66,6 @@ int main()
         os << f;
         assert( (os.flags() & std::ios_base::uppercase));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp
index 763be3a8382..b10330b7c69 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ios_base.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -57,4 +57,6 @@ int main()
         os << std::uppercase;
         assert( (os.flags() & std::ios_base::uppercase));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp
index ab39c28aac6..e57e5412c39 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/ostream.pass.cpp
@@ -57,7 +57,7 @@ f(std::basic_ostream<CharT>& os)
     return os;
 }
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -65,4 +65,6 @@ int main()
         os << f;
         assert(sb.str() == "testing...");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp
index 5668185b0cf..d2935ca734a 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/streambuf.pass.cpp
@@ -55,7 +55,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -65,4 +65,6 @@ int main()
         os << &sb2;
         assert(sb.str() == "testing...");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp
index c6a7d92180c..03cd411294b 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/endl.pass.cpp
@@ -58,7 +58,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -76,4 +76,6 @@ int main()
         assert(sync_called == 2);
         assert(os.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp
index 20703864bbe..5f18aecf907 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/ends.pass.cpp
@@ -49,7 +49,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -67,4 +67,6 @@ int main()
         assert(sb.str().back() == 0);
         assert(os.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/flush.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/flush.pass.cpp
index 8ad82cb3a30..666a92532f8 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/flush.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.manip/flush.pass.cpp
@@ -38,7 +38,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -54,4 +54,6 @@ int main()
         assert(sync_called == 2);
         assert(os.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp
index 7b7890abddd..724593f1acd 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.rvalue/CharT_pointer.pass.cpp
@@ -54,7 +54,7 @@ protected:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -66,4 +66,6 @@ int main()
         std::wostream(&sb) << L"123";
         assert(sb.str() == L"123");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp.pass.cpp
index f48ed92b8b6..7be006f1060 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp.pass.cpp
@@ -36,7 +36,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         seekpos_called = 0;
@@ -64,4 +64,6 @@ int main()
         assert(seekpos_called == 1);
         assert(os.rdstate() == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp2.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp2.pass.cpp
index 130528046e3..dc8e5ed5cd3 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp2.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/seekp2.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         seekoff_called = 0;
@@ -66,4 +66,6 @@ int main()
         assert(seekoff_called == 1);
         assert(os.rdstate() == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/tellp.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/tellp.pass.cpp
index a93032b20be..d9361e83978 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/tellp.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.seeks/tellp.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -50,4 +50,6 @@ int main()
         assert(os.tellp() == 10);
         assert(seekoff_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/flush.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/flush.pass.cpp
index f07af7471bf..15a3b59ea0a 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/flush.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/flush.pass.cpp
@@ -38,7 +38,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -50,4 +50,6 @@ int main()
         assert(os.bad());
         assert(sync_called == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp
index 4dc25175130..79f7d9f9fb8 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/put.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::wostream os((std::wstreambuf*)0);
@@ -72,4 +72,6 @@ int main()
         assert(sb.str() == "a");
         assert(os.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp
index 4b804a501ff..9ebfdf54b50 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.unformatted/write.pass.cpp
@@ -48,7 +48,7 @@ protected:
         }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::wostream os((std::wstreambuf*)0);
@@ -72,4 +72,6 @@ int main()
         assert(sb.str() == s);
         assert(os.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream/types.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream/types.pass.cpp
index dbdb52ee749..e0e9cddde41 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream/types.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <ostream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_ios<char>, std::basic_ostream<char> >::value), "");
     static_assert((std::is_same<std::basic_ostream<char>::char_type, char>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<std::basic_ostream<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_ostream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_ostream<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/construct.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/construct.pass.cpp
index f7d78537eb7..c21776a9aa4 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/construct.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/construct.pass.cpp
@@ -33,7 +33,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -57,4 +57,6 @@ int main()
         assert(bool(s));
         assert(sync_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/destruct.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/destruct.pass.cpp
index ab67442d7b6..66ed0acba26 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/destruct.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/destruct.pass.cpp
@@ -35,7 +35,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ostream os((std::streambuf*)0);
@@ -75,4 +75,6 @@ int main()
         assert(sync_called == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp b/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp
index c39c0808716..1e54e5657ef 100644
--- a/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp
@@ -123,7 +123,7 @@ void test_padding () {
 }
 
 
-int main()
+int main(int, char**)
 {
     both_ways ( "" );   // This is a compilation check
 
@@ -173,8 +173,12 @@ int main()
     assert ( unquote (  "" ) ==  "" ); // nothing there
     assert ( unquote ( L"" ) == L"" ); // nothing there
     test_padding ();
-    }
+    
+    return 0;
+}
 
 #else
-int main() {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_char.fail.cpp b/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_char.fail.cpp
index d7b33cdf230..4b343013e25 100644
--- a/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_char.fail.cpp
+++ b/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_char.fail.cpp
@@ -30,7 +30,7 @@ void round_trip ( const char *p ) {
 
 
 
-int main()
+int main(int, char**)
 {
     round_trip ( "Hi Mom" );
 }
diff --git a/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_traits.fail.cpp b/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_traits.fail.cpp
index 257826b7dbf..b19eea376d8 100644
--- a/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_traits.fail.cpp
+++ b/libcxx/test/std/input.output/iostream.format/quoted.manip/quoted_traits.fail.cpp
@@ -36,7 +36,7 @@ void round_trip ( const char *p ) {
 
 
 
-int main()
+int main(int, char**)
 {
     round_trip ( "Hi Mom" );
 }
diff --git a/libcxx/test/std/input.output/iostream.format/std.manip/resetiosflags.pass.cpp b/libcxx/test/std/input.output/iostream.format/std.manip/resetiosflags.pass.cpp
index 82ef40c9a12..637aa4ee317 100644
--- a/libcxx/test/std/input.output/iostream.format/std.manip/resetiosflags.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/std.manip/resetiosflags.pass.cpp
@@ -22,7 +22,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -52,4 +52,6 @@ int main()
         os << std::resetiosflags(std::ios_base::skipws);
         assert(!(os.flags() & std::ios_base::skipws));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/std.manip/setbase.pass.cpp b/libcxx/test/std/input.output/iostream.format/std.manip/setbase.pass.cpp
index 83d4960c420..580ae4d24c3 100644
--- a/libcxx/test/std/input.output/iostream.format/std.manip/setbase.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/std.manip/setbase.pass.cpp
@@ -22,7 +22,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -72,4 +72,6 @@ int main()
         os << std::setbase(15);
         assert((os.flags() & std::ios_base::basefield) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/std.manip/setfill.pass.cpp b/libcxx/test/std/input.output/iostream.format/std.manip/setfill.pass.cpp
index cc548b37ddd..4398ff61301 100644
--- a/libcxx/test/std/input.output/iostream.format/std.manip/setfill.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/std.manip/setfill.pass.cpp
@@ -21,7 +21,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -35,4 +35,6 @@ int main()
         os << std::setfill(L'*');
         assert(os.fill() == L'*');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/std.manip/setiosflags.pass.cpp b/libcxx/test/std/input.output/iostream.format/std.manip/setiosflags.pass.cpp
index f4bf9e7f4fd..ccf605ad7ad 100644
--- a/libcxx/test/std/input.output/iostream.format/std.manip/setiosflags.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/std.manip/setiosflags.pass.cpp
@@ -22,7 +22,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -52,4 +52,6 @@ int main()
         os << std::setiosflags(std::ios_base::oct);
         assert(os.flags() & std::ios_base::oct);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/std.manip/setprecision.pass.cpp b/libcxx/test/std/input.output/iostream.format/std.manip/setprecision.pass.cpp
index eef401c63e5..e570faf7cb7 100644
--- a/libcxx/test/std/input.output/iostream.format/std.manip/setprecision.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/std.manip/setprecision.pass.cpp
@@ -22,7 +22,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -48,4 +48,6 @@ int main()
         os << std::setprecision(10);
         assert(os.precision() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.format/std.manip/setw.pass.cpp b/libcxx/test/std/input.output/iostream.format/std.manip/setw.pass.cpp
index cd5e3f2b3e9..44aa41e5746 100644
--- a/libcxx/test/std/input.output/iostream.format/std.manip/setw.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/std.manip/setw.pass.cpp
@@ -22,7 +22,7 @@ struct testbuf
     testbuf() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb;
@@ -48,4 +48,6 @@ int main()
         os << std::setw(10);
         assert(os.width() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.forward/iosfwd.pass.cpp b/libcxx/test/std/input.output/iostream.forward/iosfwd.pass.cpp
index 1caadd1c099..5c60dcca286 100644
--- a/libcxx/test/std/input.output/iostream.forward/iosfwd.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.forward/iosfwd.pass.cpp
@@ -17,7 +17,7 @@ template <class Ptr> void test()
     ((void)p); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test<std::char_traits<char>*          >();
     test<std::char_traits<wchar_t>*       >();
@@ -119,4 +119,6 @@ int main()
     test<std::fpos<std::mbstate_t>*>();
     test<std::streampos*           >();
     test<std::wstreampos*          >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cerr.pass.cpp b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cerr.pass.cpp
index 1c046bcf447..ef3cbf676aa 100644
--- a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cerr.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cerr.pass.cpp
@@ -13,7 +13,7 @@
 #include <iostream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::cerr << "Hello World!\n";
@@ -25,4 +25,6 @@ int main()
 #endif
     assert(std::cerr.flags() & std::ios_base::unitbuf);
 #endif  // 0
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cin.pass.cpp b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cin.pass.cpp
index cce1f3eaf62..d28255043b6 100644
--- a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cin.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cin.pass.cpp
@@ -15,7 +15,7 @@
 #include <iostream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::cout << "Hello World!\n";
@@ -30,4 +30,6 @@ int main()
     assert(std::cin.tie() == &std::cout);
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/clog.pass.cpp b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/clog.pass.cpp
index 49fffca4286..97e67fddf81 100644
--- a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/clog.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/clog.pass.cpp
@@ -12,11 +12,13 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::clog << "Hello World!\n";
 #else
     (void)std::clog;
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cout.pass.cpp b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cout.pass.cpp
index d470956e284..44ae0857792 100644
--- a/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cout.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/narrow.stream.objects/cout.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::cout << "Hello World!\n";
@@ -25,4 +25,6 @@ int main()
 #else  // 0
     (void)std::cout;
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcerr.pass.cpp b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcerr.pass.cpp
index 516f3b8c994..0af3f5ee7e5 100644
--- a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcerr.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcerr.pass.cpp
@@ -13,7 +13,7 @@
 #include <iostream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::wcerr << L"Hello World!\n";
@@ -25,4 +25,6 @@ int main()
 #endif
     assert(std::wcerr.flags() & std::ios_base::unitbuf);
 #endif  // 0
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcin.pass.cpp b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcin.pass.cpp
index 862f2203456..68c1528602b 100644
--- a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcin.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcin.pass.cpp
@@ -15,7 +15,7 @@
 #include <iostream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::wcout << L"Hello World!\n";
@@ -30,4 +30,6 @@ int main()
     assert(std::wcin.tie() == &std::wcout);
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wclog.pass.cpp b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wclog.pass.cpp
index a6883b25704..ad7e35b5151 100644
--- a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wclog.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wclog.pass.cpp
@@ -12,11 +12,13 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::wclog << L"Hello World!\n";
 #else
     (void)std::wclog;
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcout.pass.cpp b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcout.pass.cpp
index ec5bb50ecb0..5703c61639d 100644
--- a/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcout.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.objects/wide.stream.objects/wcout.pass.cpp
@@ -14,11 +14,13 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
 #if 0
     std::wcout << L"Hello World!\n";
 #else
     (void)std::wcout;
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.members/state.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.members/state.pass.cpp
index 9c4d74dcd09..3938d79804c 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.members/state.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.members/state.pass.cpp
@@ -15,9 +15,11 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::fpos<int> f;
     f.state(3);
     assert(f.state() == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/addition.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/addition.pass.cpp
index 1b58566088c..30bdabc368c 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/addition.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/addition.pass.cpp
@@ -15,7 +15,7 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::fpos<std::mbstate_t> P;
     P p(5);
@@ -24,4 +24,6 @@ int main()
     assert(q == P(11));
     p += o;
     assert(p == q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/ctor_int.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/ctor_int.pass.cpp
index ff30e81afbc..e27c9068784 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/ctor_int.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/ctor_int.pass.cpp
@@ -15,9 +15,11 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::fpos<std::mbstate_t> P;
     P p(5);
     assert(p == P(5));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/difference.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/difference.pass.cpp
index 405c98899fc..114e382a71f 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/difference.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/difference.pass.cpp
@@ -15,11 +15,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::fpos<std::mbstate_t> P;
     P p(11);
     P q(6);
     std::streamoff o = p - q;
     assert(o == 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/eq_int.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/eq_int.pass.cpp
index 20ffe33c413..1b1a5f33d1c 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/eq_int.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/eq_int.pass.cpp
@@ -15,11 +15,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::fpos<std::mbstate_t> P;
     P p(5);
     P q(6);
     assert(p == p);
     assert(p != q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/offset.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/offset.pass.cpp
index 108cffdf90f..a8e763f7245 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/offset.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/offset.pass.cpp
@@ -15,10 +15,12 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::fpos<std::mbstate_t> P;
     P p(std::streamoff(7));
     std::streamoff offset(p);
     assert(offset == 7);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/streamsize.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/streamsize.pass.cpp
index e6cb51ae174..9d9cd79024e 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/streamsize.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/streamsize.pass.cpp
@@ -13,11 +13,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::streamoff o(5);
     std::streamsize sz(o);
     assert(sz == 5);
     std::streamoff o2(sz);
     assert(o == o2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/subtraction.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/subtraction.pass.cpp
index 9991be4f953..b38378b7e8c 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/subtraction.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/subtraction.pass.cpp
@@ -15,7 +15,7 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::fpos<std::mbstate_t> P;
     P p(11);
@@ -24,4 +24,6 @@ int main()
     assert(q == P(5));
     p -= o;
     assert(p == q);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/fpos/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.base/fpos/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.base/fpos/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/fpos/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags.pass.cpp
index 1a958b615b9..da147bd82f8 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags.pass.cpp
@@ -25,8 +25,10 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     const test t;
     assert(t.flags() == (test::skipws | test::dec));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags_fmtflags.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags_fmtflags.pass.cpp
index 0f49701fbf2..ed39a54245a 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags_fmtflags.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/flags_fmtflags.pass.cpp
@@ -25,11 +25,13 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.flags() == (test::skipws | test::dec));
     test::fmtflags f = t.flags(test::hex | test::right);
     assert(f == (test::skipws | test::dec));
     assert(t.flags() == (test::hex | test::right));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision.pass.cpp
index d22ca2647b5..f6387c828f2 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision.pass.cpp
@@ -25,8 +25,10 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     const test t;
     assert(t.precision() == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision_streamsize.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision_streamsize.pass.cpp
index ab38ab3d5e8..475ddc47f8a 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision_streamsize.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/precision_streamsize.pass.cpp
@@ -25,11 +25,13 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.precision() == 6);
     std::streamsize p = t.precision(10);
     assert(p == 6);
     assert(t.precision() == 10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags.pass.cpp
index da742974dab..d8ca9cc8239 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags.pass.cpp
@@ -25,11 +25,13 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.flags() == (test::skipws | test::dec));
     test::fmtflags f = t.setf(test::hex | test::right);
     assert(f == (test::skipws | test::dec));
     assert(t.flags() == (test::skipws | test::dec | test::hex | test::right));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags_mask.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags_mask.pass.cpp
index 00ce003dada..6793ced7fe0 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags_mask.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/setf_fmtflags_mask.pass.cpp
@@ -25,11 +25,13 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.flags() == (test::skipws | test::dec));
     test::fmtflags f = t.setf(test::hex | test::right, test::dec | test::right);
     assert(f == (test::skipws | test::dec));
     assert(t.flags() == (test::skipws | test::right));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/unsetf_mask.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/unsetf_mask.pass.cpp
index 49a55cb4023..f20acff1347 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/unsetf_mask.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/unsetf_mask.pass.cpp
@@ -25,10 +25,12 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.flags() == (test::skipws | test::dec));
     t.unsetf(test::dec | test::right);
     assert(t.flags() == test::skipws);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width.pass.cpp
index d812aa291f1..fc2601a4567 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width.pass.cpp
@@ -25,8 +25,10 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     const test t;
     assert(t.width() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width_streamsize.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width_streamsize.pass.cpp
index 7c906094804..3b389e5fd22 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width_streamsize.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/fmtflags.state/width_streamsize.pass.cpp
@@ -25,11 +25,13 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.width() == 0);
     std::streamsize w = t.width(4);
     assert(w == 0);
     assert(t.width() == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.callback/register_callback.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.callback/register_callback.pass.cpp
index 3de42eabc4a..316d23a528b 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.callback/register_callback.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.callback/register_callback.pass.cpp
@@ -43,7 +43,7 @@ void f1(std::ios_base::event ev, std::ios_base& stream, int index)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test t;
     std::ios_base& b = t;
@@ -52,4 +52,6 @@ int main()
     b.register_callback(f1, 4);
     std::locale l = b.imbue(std::locale(LOCALE_en_US_UTF_8));
     assert(f1_called == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.cons/dtor.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.cons/dtor.pass.cpp
index 12434f5a219..7c78ea5667d 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.cons/dtor.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.cons/dtor.pass.cpp
@@ -70,7 +70,7 @@ void f3(std::ios_base::event ev, std::ios_base& stream, int index)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -82,4 +82,6 @@ int main()
     assert(f1_called);
     assert(f2_called);
     assert(f3_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/getloc.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/getloc.pass.cpp
index 821a1f51461..06b8d83c79e 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/getloc.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/getloc.pass.cpp
@@ -26,8 +26,10 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     const test t;
     assert(t.getloc().name() == std::string("C"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/imbue.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/imbue.pass.cpp
index 0fa77cb7ac2..ad8898a170f 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/imbue.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.locales/imbue.pass.cpp
@@ -74,7 +74,7 @@ void f3(std::ios_base::event ev, std::ios_base& stream, int index)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test t;
     std::ios_base& b = t;
@@ -87,4 +87,6 @@ int main()
     assert(f1_called);
     assert(f2_called);
     assert(f3_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/iword.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/iword.pass.cpp
index 467b885cebe..84eb18370c3 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/iword.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/iword.pass.cpp
@@ -29,7 +29,7 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     std::ios_base& b = t;
@@ -41,4 +41,6 @@ int main()
         for (int j = 0; j <= i; ++j)
             assert(b.iword(j) == j);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/pword.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/pword.pass.cpp
index 65aca332ac2..c4594615daa 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/pword.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/pword.pass.cpp
@@ -30,7 +30,7 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     std::ios_base& b = t;
@@ -42,4 +42,6 @@ int main()
         for (std::intptr_t j = 0; j <= i; ++j)
             assert(b.pword(j) == (void*)j);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/xalloc.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/xalloc.pass.cpp
index dd95b26819f..2fcaddd6d54 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/xalloc.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/xalloc.pass.cpp
@@ -15,11 +15,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::ios_base::xalloc() == 0);
     assert(std::ios_base::xalloc() == 1);
     assert(std::ios_base::xalloc() == 2);
     assert(std::ios_base::xalloc() == 3);
     assert(std::ios_base::xalloc() == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.members.static/sync_with_stdio.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.members.static/sync_with_stdio.pass.cpp
index 8937f2585bf..cd219971e54 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.members.static/sync_with_stdio.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.members.static/sync_with_stdio.pass.cpp
@@ -13,7 +13,7 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert( std::ios_base::sync_with_stdio(false));
     assert(!std::ios_base::sync_with_stdio(false));
@@ -23,4 +23,6 @@ int main()
     assert( std::ios_base::sync_with_stdio(false));
     assert(!std::ios_base::sync_with_stdio());
     assert( std::ios_base::sync_with_stdio());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_char_pointer_error_code.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_char_pointer_error_code.pass.cpp
index 0fc16259974..382aeda4f11 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_char_pointer_error_code.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_char_pointer_error_code.pass.cpp
@@ -17,7 +17,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::string what_arg("io test message");
@@ -37,4 +37,6 @@ int main()
         assert(what_message.find(std::iostream_category().message(static_cast<int>
             (std::io_errc::stream))) != std::string::npos);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_string_error_code.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_string_error_code.pass.cpp
index cc607d9458d..610e6ad1527 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_string_error_code.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_failure/ctor_string_error_code.pass.cpp
@@ -17,7 +17,7 @@
 #include <system_error>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     // LWG2462 std::ios_base::failure is overspecified
     static_assert((std::is_base_of<std::system_error, std::ios_base::failure>::value), "");
@@ -40,4 +40,6 @@ int main()
         assert(what_message.find(std::iostream_category().message(static_cast<int>
             (std::io_errc::stream))) != std::string::npos);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_fmtflags/fmtflags.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_fmtflags/fmtflags.pass.cpp
index 6a51484f3f7..2eed477b0dd 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_fmtflags/fmtflags.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_fmtflags/fmtflags.pass.cpp
@@ -32,7 +32,7 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::ios_base::boolalpha);
     assert(std::ios_base::dec);
@@ -77,4 +77,6 @@ int main()
                                       | std::ios_base::hex));
     assert(std::ios_base::floatfield == (std::ios_base::scientific
                                        | std::ios_base::fixed));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_iostate/iostate.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_iostate/iostate.pass.cpp
index 64123e5d186..7e982f25f5f 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_iostate/iostate.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_iostate/iostate.pass.cpp
@@ -18,7 +18,7 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::ios_base::badbit);
     assert(std::ios_base::eofbit);
@@ -32,4 +32,6 @@ int main()
     );
 
     assert(std::ios_base::goodbit == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_openmode/openmode.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_openmode/openmode.pass.cpp
index 88c292955d3..ab21f96b7fc 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_openmode/openmode.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_openmode/openmode.pass.cpp
@@ -20,7 +20,7 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::ios_base::app);
     assert(std::ios_base::ate);
@@ -38,4 +38,6 @@ int main()
         & std::ios_base::out
         & std::ios_base::trunc) == 0
     );
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_seekdir/seekdir.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_seekdir/seekdir.pass.cpp
index 3d0c80974fe..dfa955c7f55 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_seekdir/seekdir.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_seekdir/seekdir.pass.cpp
@@ -17,9 +17,11 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::ios_base::beg != std::ios_base::cur);
     assert(std::ios_base::beg != std::ios_base::end);
     assert(std::ios_base::cur != std::ios_base::end);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/nothing_to_do.pass.cpp
index 8e23732f09f..c4eff25bcb1 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios.base/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/nothing_to_do.pass.cpp
@@ -10,6 +10,8 @@
 
 #include <ios>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.cons/ctor_streambuf.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.cons/ctor_streambuf.pass.cpp
index 1bd33e96170..01c0d4679bc 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.cons/ctor_streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.cons/ctor_streambuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <streambuf>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::streambuf* sb = 0;
@@ -44,4 +44,6 @@ int main()
         assert(ios.fill() == ' ');
         assert(ios.getloc() == std::locale());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/copyfmt.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/copyfmt.pass.cpp
index 08d00c1c0a9..949c87e0b83 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/copyfmt.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/copyfmt.pass.cpp
@@ -110,7 +110,7 @@ void g3(std::ios_base::event ev, std::ios_base& stream, int index)
     }
 }
 
-int main()
+int main(int, char**)
 {
     testbuf sb1;
     std::ios ios1(&sb1);
@@ -190,4 +190,6 @@ int main()
     assert(ios1.tie() == (std::ostream*)2);
     assert(ios1.fill() == '2');
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill.pass.cpp
index b5cc96c3384..f45c6c8b25c 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill.pass.cpp
@@ -15,8 +15,10 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::ios ios(0);
     assert(ios.fill() == ' ');
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill_char_type.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill_char_type.pass.cpp
index b1c56ed539d..1c42a03fb31 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill_char_type.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/fill_char_type.pass.cpp
@@ -15,11 +15,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     assert(ios.fill() == ' ');
     char c = ios.fill('*');
     assert(c == ' ');
     assert(ios.fill() == '*');
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/imbue.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/imbue.pass.cpp
index 3874372902f..ed0df788daa 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/imbue.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/imbue.pass.cpp
@@ -68,7 +68,7 @@ void f3(std::ios_base::event ev, std::ios_base& stream, int index)
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -99,4 +99,6 @@ int main()
         assert(f2_called);
         assert(f3_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/move.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/move.pass.cpp
index 4c60756746e..5f99f3db0ae 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/move.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/move.pass.cpp
@@ -77,7 +77,7 @@ void g3(std::ios_base::event ev, std::ios_base&, int index)
     }
 }
 
-int main()
+int main(int, char**)
 {
     testios ios1;
     testbuf sb2;
@@ -136,4 +136,6 @@ int main()
 
     assert(ios2.rdbuf() == &sb2);
     assert(ios2.tie() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/narrow.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/narrow.pass.cpp
index b1ffc1e96d6..afab4ec5def 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/narrow.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/narrow.pass.cpp
@@ -15,9 +15,11 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::wios ios(0);
     assert(ios.narrow(L'c', '*') == 'c');
     assert(ios.narrow(L'\u203C', '*') == '*');
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf.pass.cpp
index bc5871f924d..f104cada627 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <streambuf>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::ios ios(0);
@@ -27,4 +27,6 @@ int main()
         const std::ios ios(sb);
         assert(ios.rdbuf() == sb);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf_streambuf.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf_streambuf.pass.cpp
index c1aa1aaf3de..5c4e24a82eb 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf_streambuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/rdbuf_streambuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <streambuf>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     assert(ios.rdbuf() == 0);
@@ -30,4 +30,6 @@ int main()
     assert(sb2 == (std::streambuf*)1);
     assert(ios.rdbuf() == 0);
     assert(ios.bad());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/set_rdbuf.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/set_rdbuf.pass.cpp
index 65f66cb4b63..04b1b9ff6b0 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/set_rdbuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/set_rdbuf.pass.cpp
@@ -30,7 +30,7 @@ struct testios
     void set_rdbuf(std::streambuf* x) {std::ios::set_rdbuf(x);}
 };
 
-int main()
+int main(int, char**)
 {
     testbuf sb1;
     testbuf sb2;
@@ -60,4 +60,6 @@ int main()
 #endif
     ios.set_rdbuf(0);
     assert(ios.rdbuf() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/swap.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/swap.pass.cpp
index 559768b945b..40e95bae704 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/swap.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/swap.pass.cpp
@@ -70,7 +70,7 @@ void g3(std::ios_base::event, std::ios_base&, int index)
     g3_called = true;
 }
 
-int main()
+int main(int, char**)
 {
     testbuf sb1;
     testios ios1(&sb1);
@@ -164,4 +164,6 @@ int main()
     ios2.imbue(std::locale("C"));
     assert(f1_called);
     assert(f2_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie.pass.cpp
index 6ea816d7d1b..c0d7ac17332 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie.pass.cpp
@@ -15,8 +15,10 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::basic_ios<char> ios(0);
     assert(ios.tie() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie_ostream.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie_ostream.pass.cpp
index d2bb41c4e28..4ce5966add8 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie_ostream.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/tie_ostream.pass.cpp
@@ -15,11 +15,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ostream* os = (std::ostream*)1;
     std::ostream* r = ios.tie(os);
     assert(r == 0);
     assert(ios.tie() == os);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/widen.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/widen.pass.cpp
index a1585cd545e..0ae5637184c 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/widen.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/basic.ios.members/widen.pass.cpp
@@ -15,8 +15,10 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::ios ios(0);
     assert(ios.widen('c') == 'c');
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bad.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bad.pass.cpp
index 158c953a401..2308cfa929f 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bad.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bad.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -37,4 +37,6 @@ int main()
         ios.setstate(std::ios::badbit);
         assert(ios.bad());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp
index 126431ce20d..24fcbff3926 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     assert(static_cast<bool>(ios) == !ios.fail());
@@ -30,4 +30,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((!std::is_convertible<std::ios, bool>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/clear.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/clear.pass.cpp
index 7938a84cfe4..6fc38fde9ba 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/clear.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/clear.pass.cpp
@@ -20,7 +20,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -66,4 +66,6 @@ int main()
         ios.clear(std::ios::eofbit);
         assert(ios.rdstate() == std::ios::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/eof.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/eof.pass.cpp
index bf65663427f..bf1d0246d4d 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/eof.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/eof.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -33,4 +33,6 @@ int main()
         ios.setstate(std::ios::eofbit);
         assert(ios.eof());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions.pass.cpp
index 9a6b3233f7f..4632e004333 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         const std::ios ios(0);
@@ -29,4 +29,6 @@ int main()
         const std::ios ios(&sb);
         assert(ios.exceptions() == std::ios::goodbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions_iostate.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions_iostate.pass.cpp
index 1d56d475a9e..b8b6577b243 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions_iostate.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/exceptions_iostate.pass.cpp
@@ -20,7 +20,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -48,4 +48,6 @@ int main()
         ios.exceptions(std::ios::badbit);
         assert(ios.exceptions() == std::ios::badbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/fail.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/fail.pass.cpp
index a475c3589ab..3ae215e45f4 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/fail.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/fail.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -37,4 +37,6 @@ int main()
         ios.setstate(std::ios::failbit);
         assert(ios.fail());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/good.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/good.pass.cpp
index e4f28bfe325..19c05edce67 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/good.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/good.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -31,4 +31,6 @@ int main()
         ios.setstate(std::ios::eofbit);
         assert(!ios.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/not.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/not.pass.cpp
index 151c2244e80..20ddb35dcca 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/not.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/not.pass.cpp
@@ -15,10 +15,12 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     assert(!ios == ios.fail());
     ios.setstate(std::ios::failbit);
     assert(!ios == ios.fail());
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/rdstate.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/rdstate.pass.cpp
index dde113a918c..37886ac83e2 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/rdstate.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/rdstate.pass.cpp
@@ -15,10 +15,12 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     assert(ios.rdstate() == std::ios::badbit);
     ios.setstate(std::ios::failbit);
     assert(ios.rdstate() == (std::ios::failbit | std::ios::badbit));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/setstate.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/setstate.pass.cpp
index 830dd448ef1..ea954bee05e 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/setstate.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/setstate.pass.cpp
@@ -20,7 +20,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     {
         std::ios ios(0);
@@ -65,4 +65,6 @@ int main()
         ios.setstate(std::ios::failbit);
         assert(ios.rdstate() == (std::ios::eofbit | std::ios::failbit));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/ios/types.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/types.pass.cpp
index 58165fc4444..b4a4d7c57d8 100644
--- a/libcxx/test/std/input.output/iostreams.base/ios/types.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/ios/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <ios>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::ios_base, std::basic_ios<char> >::value), "");
     static_assert((std::is_same<std::basic_ios<char>::char_type, char>::value), "");
@@ -29,4 +29,6 @@ int main()
     static_assert((std::is_same<std::basic_ios<char>::int_type, std::char_traits<char>::int_type>::value), "");
     static_assert((std::is_same<std::basic_ios<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_ios<char>::off_type, std::char_traits<char>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/is_error_code_enum_io_errc.pass.cpp b/libcxx/test/std/input.output/iostreams.base/is_error_code_enum_io_errc.pass.cpp
index c087871ea84..76eb83148b3 100644
--- a/libcxx/test/std/input.output/iostreams.base/is_error_code_enum_io_errc.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/is_error_code_enum_io_errc.pass.cpp
@@ -15,10 +15,12 @@
 #include <ios>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_error_code_enum  <std::io_errc>::value, "");
 #if TEST_STD_VER > 14
     static_assert(std::is_error_code_enum_v<std::io_errc>, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/internal.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/internal.pass.cpp
index a214813984e..fba2e71ca7d 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/internal.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/internal.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::internal(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::internal);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/left.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/left.pass.cpp
index 1073e2522be..f89d6b9e78f 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/left.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/left.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::left(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::left);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/right.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/right.pass.cpp
index c391ab8c500..399d3ba51dc 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/right.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/adjustfield.manip/right.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::right(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::right);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/dec.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/dec.pass.cpp
index 64351b6b192..98740cdc026 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/dec.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/dec.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::dec(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::dec);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/hex.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/hex.pass.cpp
index cab0bc25834..39addcdcf24 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/hex.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/hex.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::hex(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::hex);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/oct.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/oct.pass.cpp
index a4073646c4e..92b2d4ee7ef 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/oct.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/basefield.manip/oct.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::oct(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::oct);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/iostream_category.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/iostream_category.pass.cpp
index 0517481b899..e017c632a4d 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/iostream_category.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/iostream_category.pass.cpp
@@ -14,9 +14,11 @@
 #include <cassert>
 #include <string>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat1 = std::iostream_category();
     std::string m1 = e_cat1.name();
     assert(m1 == "iostream");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_code.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_code.pass.cpp
index 745349d14cb..060b6284cac 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_code.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_code.pass.cpp
@@ -13,11 +13,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec = make_error_code(std::io_errc::stream);
         assert(ec.value() == static_cast<int>(std::io_errc::stream));
         assert(ec.category() == std::iostream_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_condition.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_condition.pass.cpp
index ce9f9f02052..3970708bfa0 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_condition.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/error.reporting/make_error_condition.pass.cpp
@@ -13,11 +13,13 @@
 #include <ios>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_condition ec1 = std::make_error_condition(std::io_errc::stream);
         assert(ec1.value() == static_cast<int>(std::io_errc::stream));
         assert(ec1.category() == std::iostream_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/defaultfloat.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/defaultfloat.pass.cpp
index 7f04bbc51e7..bb8c424a162 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/defaultfloat.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/defaultfloat.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::fixed));
     assert(!(ios.flags() & std::ios::scientific));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/fixed.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/fixed.pass.cpp
index 8dbb7a1d8b4..94cbf1a53d9 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/fixed.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/fixed.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::fixed(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::fixed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/hexfloat.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/hexfloat.pass.cpp
index 24afef8b86e..c24d7f999d9 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/hexfloat.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/hexfloat.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     assert(&r == &ios);
     assert(ios.flags() & std::ios::fixed);
     assert(ios.flags() & std::ios::scientific);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/scientific.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/scientific.pass.cpp
index d84aa3775a0..c8a4819447b 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/scientific.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/floatfield.manip/scientific.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::scientific(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::scientific);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/boolalpha.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/boolalpha.pass.cpp
index de58c17f060..176267dd6fe 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/boolalpha.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/boolalpha.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::boolalpha(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::boolalpha);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noboolalpha.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noboolalpha.pass.cpp
index f67ddabaea3..27d61cee7aa 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noboolalpha.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noboolalpha.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::noboolalpha(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::boolalpha));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowbase.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowbase.pass.cpp
index bd904ad6419..b730afa88ba 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowbase.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowbase.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::noshowbase(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::showbase));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpoint.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpoint.pass.cpp
index 97d9198014c..0d9f33ea5c1 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpoint.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpoint.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::noshowpoint(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::showpoint));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpos.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpos.pass.cpp
index 24f8bfca0b0..fa54cd64735 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpos.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noshowpos.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::noshowpos(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::showpos));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noskipws.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noskipws.pass.cpp
index 5d24d3d4190..9ee5ea8e61a 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noskipws.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/noskipws.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::noskipws(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::skipws));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nounitbuf.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nounitbuf.pass.cpp
index 61a7dd29e83..ce06e12bd11 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nounitbuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nounitbuf.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::nounitbuf(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::unitbuf));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nouppercase.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nouppercase.pass.cpp
index 923a6ac754a..8e055462099 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nouppercase.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/nouppercase.pass.cpp
@@ -18,7 +18,7 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
@@ -26,4 +26,6 @@ int main()
     std::ios_base& r = std::nouppercase(ios);
     assert(&r == &ios);
     assert(!(ios.flags() & std::ios::uppercase));
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showbase.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showbase.pass.cpp
index d584d3128a8..7f1338c5dbf 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showbase.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showbase.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::showbase(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::showbase);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpoint.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpoint.pass.cpp
index 6cfb73633d1..03cf312d0f3 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpoint.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpoint.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::showpoint(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::showpoint);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpos.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpos.pass.cpp
index 06f1dd83620..2fb0d651154 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpos.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/showpos.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::showpos(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::showpos);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/skipws.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/skipws.pass.cpp
index b153bc84018..2c64cb8dfb1 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/skipws.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/skipws.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::skipws(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::skipws);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/unitbuf.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/unitbuf.pass.cpp
index 22bcf5eb99e..6acedc6a5c2 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/unitbuf.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/unitbuf.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::unitbuf(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::unitbuf);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/uppercase.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/uppercase.pass.cpp
index cc2a4bc45e8..e97763fff03 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/uppercase.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/fmtflags.manip/uppercase.pass.cpp
@@ -18,11 +18,13 @@
 
 struct testbuf : public std::streambuf {};
 
-int main()
+int main(int, char**)
 {
     testbuf sb;
     std::ios ios(&sb);
     std::ios_base& r = std::uppercase(ios);
     assert(&r == &ios);
     assert(ios.flags() & std::ios::uppercase);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.base/std.ios.manip/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/std.ios.manip/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/stream.types/streamoff.pass.cpp b/libcxx/test/std/input.output/iostreams.base/stream.types/streamoff.pass.cpp
index aaa5b871ac2..20b953d5527 100644
--- a/libcxx/test/std/input.output/iostreams.base/stream.types/streamoff.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/stream.types/streamoff.pass.cpp
@@ -13,8 +13,10 @@
 #include <ios>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_integral<std::streamoff>::value, "");
     static_assert(std::is_signed<std::streamoff>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.base/stream.types/streamsize.pass.cpp b/libcxx/test/std/input.output/iostreams.base/stream.types/streamsize.pass.cpp
index 67093232456..50fa21e8d52 100644
--- a/libcxx/test/std/input.output/iostreams.base/stream.types/streamsize.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.base/stream.types/streamsize.pass.cpp
@@ -13,8 +13,10 @@
 #include <ios>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_integral<std::streamsize>::value, "");
     static_assert(std::is_signed<std::streamsize>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.requirements/iostream.limits.imbue/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/iostreams.requirements/iostream.limits.imbue/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.requirements/iostream.limits.imbue/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.requirements/iostream.limits.imbue/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.requirements/iostreams.limits.pos/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.requirements/iostreams.limits.pos/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.requirements/iostreams.limits.pos/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.requirements/iostreams.limits.pos/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.requirements/iostreams.threadsafety/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.requirements/iostreams.threadsafety/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.requirements/iostreams.threadsafety/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.requirements/iostreams.threadsafety/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/iostreams.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/iostreams.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/iostreams.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/iostreams.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf.reqts/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf.reqts/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf.reqts/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf.reqts/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.fail.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.fail.cpp
index b94714212b1..285485087b4 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.fail.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.fail.cpp
@@ -18,7 +18,9 @@
 
 std::streambuf &get();
 
-int main()
+int main(int, char**)
 {
     std::streambuf sb = get(); // expected-error {{calling a protected constructor}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.pass.cpp
index c2989929174..405c7299591 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.pass.cpp
@@ -49,7 +49,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -82,4 +82,6 @@ int main()
         test<wchar_t> t;
         test<wchar_t> t2 = t;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.fail.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.fail.cpp
index 76d47f2a237..ec7650ae04e 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.fail.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.fail.cpp
@@ -15,7 +15,9 @@
 
 #include <streambuf>
 
-int main()
+int main(int, char**)
 {
     std::basic_streambuf<char> sb;
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.pass.cpp
index 9eebf255760..15475d3d684 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/default.pass.cpp
@@ -35,7 +35,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -54,4 +54,6 @@ int main()
         test<wchar_t> t;
         assert(t.getloc().name() == LOCALE_en_US_UTF_8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekoff.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekoff.pass.cpp
index 741b71e38c2..b49fc2094ed 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekoff.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekoff.pass.cpp
@@ -24,11 +24,13 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
         assert(t.pubseekoff(0, std::ios_base::beg) == -1);
         assert(t.pubseekoff(0, std::ios_base::beg, std::ios_base::app) == -1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekpos.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekpos.pass.cpp
index 2e14de9d28f..1095c9148c7 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekpos.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubseekpos.pass.cpp
@@ -24,10 +24,12 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
         assert(t.pubseekpos(0, std::ios_base::app) == -1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsetbuf.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsetbuf.pass.cpp
index fae4dd78fd6..c0efb1710ab 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsetbuf.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsetbuf.pass.cpp
@@ -23,10 +23,12 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
         assert(t.pubsetbuf(0, 0) == &t);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsync.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsync.pass.cpp
index 8433a9f31a9..8d7528ee261 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsync.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.buffer/pubsync.pass.cpp
@@ -23,10 +23,12 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
         assert(t.pubsync() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.locales/locales.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.locales/locales.pass.cpp
index ed1d43a8666..835944fcf31 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.locales/locales.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.locales/locales.pass.cpp
@@ -34,7 +34,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -48,4 +48,6 @@ int main()
                LOCALE_en_US_UTF_8);
         assert(t.getloc().name() == LOCALE_fr_FR_UTF_8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/in_avail.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/in_avail.pass.cpp
index ea51ac64df1..6d11a8e8969 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/in_avail.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/in_avail.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -48,4 +48,6 @@ int main()
         t.setg(in, in+2, in+5);
         assert(t.in_avail() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sbumpc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sbumpc.pass.cpp
index 4aa7a81818b..4ac2d6fe547 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sbumpc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sbumpc.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -52,4 +52,6 @@ int main()
         assert(t.sbumpc() == 'B');
         assert(uflow_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetc.pass.cpp
index 2a48158fd41..8baefb279cf 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetc.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -52,4 +52,6 @@ int main()
         assert(t.sgetc() == 'A');
         assert(underflow_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetn.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetn.pass.cpp
index 59804043cb0..9088ed846b9 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetn.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetn.pass.cpp
@@ -31,10 +31,12 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(xsgetn_called == 0);
     assert(t.sgetn(0, 0) == 10);
     assert(xsgetn_called == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/snextc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/snextc.pass.cpp
index 830f27282ef..54965bca2fc 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/snextc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/snextc.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -52,4 +52,6 @@ int main()
         assert(t.snextc() == 'C');
         assert(uflow_called == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sputbackc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sputbackc.pass.cpp
index a2546b810df..3b63ba3cef9 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sputbackc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sputbackc.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -52,4 +52,6 @@ int main()
         assert(t.sputbackc('A') == 'a');
         assert(pbackfail_called == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp
index dcdec61a3d4..07c1600b0b2 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp
@@ -38,7 +38,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -52,4 +52,6 @@ int main()
         assert(t.sungetc() == 'a');
         assert(pbackfail_called == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputc.pass.cpp
index 3d04924b160..989b61d4e19 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputc.pass.cpp
@@ -42,7 +42,7 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -59,4 +59,6 @@ int main()
         assert(out[0] == 'A');
         assert(out[1] == 'B');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputn.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputn.pass.cpp
index bb865636ca3..01bd9d487d8 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputn.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.put/sputn.pass.cpp
@@ -31,10 +31,12 @@ protected:
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(xsputn_called == 0);
     assert(t.sputn(0, 0) == 5);
     assert(xsputn_called == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/assign.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/assign.pass.cpp
index 0c1cd4efbf9..6109a6aa471 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/assign.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/assign.pass.cpp
@@ -50,7 +50,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -89,4 +89,6 @@ int main()
         test<wchar_t> t2;
         t2 = t;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/swap.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/swap.pass.cpp
index 6ece9aa57cf..2809d63124f 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/swap.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/swap.pass.cpp
@@ -59,7 +59,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -98,4 +98,6 @@ int main()
         test<wchar_t> t2;
         t2.swap(t);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/gbump.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/gbump.pass.cpp
index 015a7daa2f7..161461dee95 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/gbump.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/gbump.pass.cpp
@@ -41,7 +41,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -55,4 +55,6 @@ int main()
         t.setg(in, in+1, in+sizeof(in)/sizeof(in[0]));
         t.gbump(3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/setg.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/setg.pass.cpp
index 74152974c07..b303465f02d 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/setg.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/setg.pass.cpp
@@ -33,7 +33,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -45,4 +45,6 @@ int main()
         wchar_t in[] = L"ABC";
         t.setg(in, in+1, in+sizeof(in)/sizeof(in[0]));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump.pass.cpp
index 92b869d31e5..e151d32273c 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump.pass.cpp
@@ -41,7 +41,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -57,4 +57,6 @@ int main()
         t.pbump(3);
         t.pbump(1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump2gig.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump2gig.pass.cpp
index 5811c90196f..eee48f3dfdb 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump2gig.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/pbump2gig.pass.cpp
@@ -26,7 +26,7 @@ struct SB : std::stringbuf
   const char* pubpptr() const { return pptr(); }
 };
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     try {
@@ -40,4 +40,6 @@ int main()
     catch (const std::length_error &) {} // maybe the string can't take 2GB
     catch (const std::bad_alloc    &) {} // maybe we don't have enough RAM
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/setp.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/setp.pass.cpp
index 12f955360c9..6ca36227b53 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/setp.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/setp.pass.cpp
@@ -33,7 +33,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test<char> t;
@@ -45,4 +45,6 @@ int main()
         wchar_t in[] = L"ABC";
         t.setp(in, in+sizeof(in)/sizeof(in[0]));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.buffer/tested_elsewhere.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.buffer/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.buffer/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.buffer/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/showmanyc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/showmanyc.pass.cpp
index b31408e952d..5a238e88455 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/showmanyc.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/showmanyc.pass.cpp
@@ -25,8 +25,10 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     test<char> t;
     assert(t.in_avail() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/uflow.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/uflow.pass.cpp
index 1d1ee519f58..2f86c3b1a96 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/uflow.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/uflow.pass.cpp
@@ -25,8 +25,10 @@ struct test
 
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.sgetc() == -1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/underflow.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/underflow.pass.cpp
index 2422c52e54b..1d2ce7c5c23 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/underflow.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/underflow.pass.cpp
@@ -22,8 +22,10 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.sgetc() == -1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/xsgetn.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/xsgetn.pass.cpp
index 7c5f6b9d6fe..f5a95821b28 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/xsgetn.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.get/xsgetn.pass.cpp
@@ -30,7 +30,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     char input[7] = "123456";
@@ -38,4 +38,6 @@ int main()
     char output[sizeof(input)] = {0};
     assert(t.sgetn(output, 10) == 7);
     assert(std::strcmp(input, output) == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.locales/nothing_to_do.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.locales/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.locales/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.locales/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.pback/pbackfail.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.pback/pbackfail.pass.cpp
index 1f243e958d6..217ff8c32fc 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.pback/pbackfail.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.pback/pbackfail.pass.cpp
@@ -24,8 +24,10 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.sputbackc('A') == -1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/overflow.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/overflow.pass.cpp
index ae52b9539ee..e067088f50b 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/overflow.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/overflow.pass.cpp
@@ -22,8 +22,10 @@ struct test
     test() {}
 };
 
-int main()
+int main(int, char**)
 {
     test t;
     assert(t.sputc('A') == -1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/xsputn.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/xsputn.pass.cpp
index 15d37404122..1c30c8f2836 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/xsputn.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.virtuals/streambuf.virt.put/xsputn.pass.cpp
@@ -30,7 +30,7 @@ struct test
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         test t;
@@ -41,4 +41,6 @@ int main()
         assert(t.sputn(in, sizeof(in)) == sizeof(in));
         assert(std::strcmp(in, out) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/types.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/types.pass.cpp
index d6ea963df27..434f8e3ec12 100644
--- a/libcxx/test/std/input.output/stream.buffers/streambuf/types.pass.cpp
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <streambuf>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::streambuf::char_type, char>::value), "");
     static_assert((std::is_same<std::streambuf::traits_type, std::char_traits<char> >::value), "");
@@ -35,4 +35,6 @@ int main()
     static_assert((std::is_same<std::wstreambuf::int_type, std::char_traits<wchar_t>::int_type>::value), "");
     static_assert((std::is_same<std::wstreambuf::pos_type, std::char_traits<wchar_t>::pos_type>::value), "");
     static_assert((std::is_same<std::wstreambuf::off_type, std::char_traits<wchar_t>::off_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/member_swap.pass.cpp
index cb4644aad43..d0a5863ed84 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss0(" 123 456");
@@ -52,4 +52,6 @@ int main()
         ss0 >> i;
         assert(i == 321);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/move.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/move.pass.cpp
index b906db8d5bf..5677959438f 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss0(" 123 456");
@@ -82,4 +82,6 @@ int main()
         s1 >> s;
         assert(s == L"Dddddddddddddddddd");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/nonmember_swap.pass.cpp
index 09b6e4b3996..b8b00310dbe 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.assign/nonmember_swap.pass.cpp
@@ -19,7 +19,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss0(" 123 456");
@@ -55,4 +55,6 @@ int main()
         ss0 >> i;
         assert(i == 321);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/default.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/default.pass.cpp
index 327c4ca124d..414c2269581 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss;
@@ -42,4 +42,6 @@ int main()
         assert(ss.good());
         assert(ss.str() == L"");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/move.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/move.pass.cpp
index c5b144b0920..27eb5a745c8 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss0(" 123 456");
@@ -44,4 +44,6 @@ int main()
         ss >> i;
         assert(i == 456);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/string.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/string.pass.cpp
index cf3c7d89130..04733d6042f 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.cons/string.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss(" 123 456");
@@ -63,4 +63,6 @@ int main()
         ss >> i;
         assert(i == 456);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.members/str.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.members/str.pass.cpp
index 9b706a535ac..4c010e2b434 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/istringstream.members/str.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/istringstream.members/str.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream ss(" 123 456");
@@ -52,4 +52,6 @@ int main()
         ss >> i;
         assert(i == 789);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/istringstream/types.pass.cpp b/libcxx/test/std/input.output/string.streams/istringstream/types.pass.cpp
index 0f256cbbdd4..97319644229 100644
--- a/libcxx/test/std/input.output/string.streams/istringstream/types.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/istringstream/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <sstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_istream<char>, std::basic_istringstream<char> >::value), "");
     static_assert((std::is_same<std::basic_istringstream<char>::char_type, char>::value), "");
@@ -32,4 +32,6 @@ int main()
     static_assert((std::is_same<std::basic_istringstream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_istringstream<char>::off_type, std::char_traits<char>::off_type>::value), "");
     static_assert((std::is_same<std::basic_istringstream<char>::allocator_type, std::allocator<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/member_swap.pass.cpp
index af5622ee2c9..01cc58ae6ae 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss0(" 123 456");
@@ -44,4 +44,6 @@ int main()
         ss0 << i << ' ' << 567;
         assert(ss0.str() == L"234 567");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/move.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/move.pass.cpp
index f44b0fba41a..bad3c7316d2 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss0(" 123 456");
@@ -42,4 +42,6 @@ int main()
         ss << i << ' ' << 567;
         assert(ss.str() == L"234 5676");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/nonmember_swap.pass.cpp
index 0793fd295cf..d251e6e085f 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.assign/nonmember_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss0(" 123 456");
@@ -44,4 +44,6 @@ int main()
         ss0 << i << ' ' << 567;
         assert(ss0.str() == L"234 567");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/default.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/default.pass.cpp
index 79e0f614c5a..f772a904007 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss;
@@ -42,4 +42,6 @@ int main()
         assert(ss.good());
         assert(ss.str() == L"");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/move.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/move.pass.cpp
index 569310174b8..3b562bafd52 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss0(" 123 456");
@@ -40,4 +40,6 @@ int main()
         ss << i << ' ' << 567;
         assert(ss.str() == L"234 5676");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/string.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/string.pass.cpp
index 8d64dd5e5f1..98782dce1f6 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.cons/string.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss(" 123 456");
@@ -55,4 +55,6 @@ int main()
         ss << i << ' ' << 567;
         assert(ss.str() == L"234 5676");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.members/str.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.members/str.pass.cpp
index d74acf3a588..56a85159cca 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.members/str.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/ostringstream.members/str.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream ss(" 123 456");
@@ -48,4 +48,6 @@ int main()
         ss << L"abc";
         assert(ss.str() == L"abc9");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/ostringstream/types.pass.cpp b/libcxx/test/std/input.output/string.streams/ostringstream/types.pass.cpp
index 15e7dc61faf..0da5f98d46f 100644
--- a/libcxx/test/std/input.output/string.streams/ostringstream/types.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/ostringstream/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <sstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_ostream<char>, std::basic_ostringstream<char> >::value), "");
     static_assert((std::is_same<std::basic_ostringstream<char>::char_type, char>::value), "");
@@ -32,4 +32,6 @@ int main()
     static_assert((std::is_same<std::basic_ostringstream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_ostringstream<char>::off_type, std::char_traits<char>::off_type>::value), "");
     static_assert((std::is_same<std::basic_ostringstream<char>::allocator_type, std::allocator<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/member_swap.pass.cpp
index b5dce8fb914..6977d3189cf 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf1("testing");
@@ -60,4 +60,6 @@ int main()
         assert(buf.str() == L"testing");
         assert(buf1.str() == L"");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/move.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/move.pass.cpp
index 2a469ebb79a..653edc0d19c 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/move.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf1("testing");
@@ -54,4 +54,6 @@ int main()
         buf = move(buf1);
         assert(buf.str() == L"testing");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/nonmember_swap.pass.cpp
index 5a57f902af3..38562fc3220 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign/nonmember_swap.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf1("testing");
@@ -62,4 +62,6 @@ int main()
         assert(buf.str() == L"testing");
         assert(buf1.str() == L"");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/default.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/default.pass.cpp
index 2121a7a842e..836509f2fdd 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/default.pass.cpp
@@ -31,7 +31,7 @@ struct testbuf
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf;
@@ -49,4 +49,6 @@ int main()
         testbuf<wchar_t> buf;
         buf.check();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/move.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/move.pass.cpp
index 70eff738492..a3cccd39c87 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/move.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf1("testing");
@@ -48,4 +48,6 @@ int main()
         std::wstringbuf buf(move(buf1));
         assert(buf.str() == L"testing");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/string.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/string.pass.cpp
index 607d314255b..de211c80ea1 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.cons/string.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf("testing");
@@ -43,4 +43,6 @@ int main()
         std::wstringbuf buf(L"testing", std::ios_base::out);
         assert(buf.str() == L"testing");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.members/str.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.members/str.pass.cpp
index baf406b696c..78b572454a5 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.members/str.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.members/str.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf buf("testing");
@@ -30,4 +30,6 @@ int main()
         buf.str(L"another test");
         assert(buf.str() == L"another test");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/overflow.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/overflow.pass.cpp
index 0f833070525..c9fdd0abcc9 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/overflow.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/overflow.pass.cpp
@@ -34,7 +34,7 @@ struct testbuf
     void pbump(int n) {base::pbump(n);}
 };
 
-int main()
+int main(int, char**)
 {
     {  // sanity check
     testbuf<char> tb("");
@@ -97,4 +97,6 @@ int main()
         assert(sb.sputc('2') == '2');
         assert(sb.str() == "abc12");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/pbackfail.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/pbackfail.pass.cpp
index dfbe2084b9d..458e393c8ec 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/pbackfail.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/pbackfail.pass.cpp
@@ -32,7 +32,7 @@ struct testbuf
     void pbump(int n) {base::pbump(n);}
 };
 
-int main()
+int main(int, char**)
 {
     {  // sanity check
     testbuf<char> tb("");
@@ -92,4 +92,6 @@ int main()
         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) == std::char_traits<wchar_t>::eof());
         assert(sb.str() == L"133");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp
index dbe117eaa17..1bee5c216a5 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf sb(std::ios_base::in);
@@ -163,4 +163,6 @@ int main()
         assert(sb.sputc(L'c') == L'c');
         assert(sb.str() == L"0123456c89");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekpos.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekpos.pass.cpp
index 7d687e070c1..fde91e74ba0 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekpos.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekpos.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf sb("0123456789", std::ios_base::in);
@@ -73,4 +73,6 @@ int main()
         assert(sb.sputc(L'3') == L'3');
         assert(sb.str() == L"0123456789");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/setbuf.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/setbuf.pass.cpp
index 99bc75e6c8a..f833debe39d 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/setbuf.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/setbuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringbuf sb("0123456789");
@@ -28,4 +28,6 @@ int main()
         assert(sb.pubsetbuf(0, 0) == &sb);
         assert(sb.str() == L"0123456789");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/underflow.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/underflow.pass.cpp
index c3244985749..23b77d229ca 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/underflow.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/underflow.pass.cpp
@@ -28,7 +28,7 @@ struct testbuf
     void pbump(int n) {base::pbump(n);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         testbuf<char> sb("123");
@@ -66,4 +66,6 @@ int main()
         assert(sb.underflow() == L'4');
         assert(sb.underflow() == L'4');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringbuf/types.pass.cpp b/libcxx/test/std/input.output/string.streams/stringbuf/types.pass.cpp
index 29d651fc5e5..c27db853599 100644
--- a/libcxx/test/std/input.output/string.streams/stringbuf/types.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringbuf/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <sstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_streambuf<char>, std::basic_stringbuf<char> >::value), "");
     static_assert((std::is_same<std::basic_stringbuf<char>::char_type, char>::value), "");
@@ -32,4 +32,6 @@ int main()
     static_assert((std::is_same<std::basic_stringbuf<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_stringbuf<char>::off_type, std::char_traits<char>::off_type>::value), "");
     static_assert((std::is_same<std::basic_stringbuf<char>::allocator_type, std::allocator<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/default.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/default.pass.cpp
index 571c3dc658e..11cf288fcc9 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/default.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss;
@@ -42,4 +42,6 @@ int main()
         assert(ss.good());
         assert(ss.str() == L"");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/move.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/move.pass.cpp
index 671aee55397..2a73ad9c215 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss0(" 123 456 ");
@@ -48,4 +48,6 @@ int main()
         ss << i << ' ' << 123;
         assert(ss.str() == L"456 1236 ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/move2.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/move2.pass.cpp
index 4527cae33f6..044e62824ca 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/move2.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/move2.pass.cpp
@@ -21,7 +21,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     std::vector<std::istringstream> vecis;
     vecis.push_back(std::istringstream());
@@ -34,4 +34,6 @@ int main()
         vecis[n].seekg(0, std::ios_base::beg);
         assert(vecis[n].str().size() == 31);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp
index 7bc383f9a4a..29c81b3be62 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp
@@ -27,7 +27,7 @@ struct NoDefaultAllocator : std::allocator<T>
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss(" 123 456 ");
@@ -64,4 +64,6 @@ int main()
     //  This test is not required by the standard, but *where else* could it get the allocator?
         assert(sb.str().get_allocator() == s.get_allocator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/member_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/member_swap.pass.cpp
index 07d3a1dea9d..2e0f4471a1c 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/member_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss0(" 123 456 ");
@@ -52,4 +52,6 @@ int main()
         ss0 << i << ' ' << 123;
         assert(ss0.str() == L"456 123");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/move.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/move.pass.cpp
index 0332924a69f..c3088679ed6 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/move.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/move.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss0(" 123 456 ");
@@ -50,4 +50,6 @@ int main()
         ss << i << ' ' << 123;
         assert(ss.str() == L"456 1236 ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/nonmember_swap.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/nonmember_swap.pass.cpp
index 3225b273e68..06a95dcb394 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.cons/stringstream.assign/nonmember_swap.pass.cpp
@@ -19,7 +19,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss0(" 123 456 ");
@@ -55,4 +55,6 @@ int main()
         ss0 << i << ' ' << 123;
         assert(ss0.str() == L"456 123");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream.members/str.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream.members/str.pass.cpp
index 392a1680e5c..1dc655193b8 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream.members/str.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream.members/str.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::stringstream ss(" 123 456 ");
@@ -63,4 +63,6 @@ int main()
         ss.write("\xd1", 1);
         assert(ss.str().length() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/input.output/string.streams/stringstream/types.pass.cpp b/libcxx/test/std/input.output/string.streams/stringstream/types.pass.cpp
index e05048a2df1..580ccb9a4e6 100644
--- a/libcxx/test/std/input.output/string.streams/stringstream/types.pass.cpp
+++ b/libcxx/test/std/input.output/string.streams/stringstream/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <sstream>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::basic_iostream<char>, std::basic_stringstream<char> >::value), "");
     static_assert((std::is_same<std::basic_stringstream<char>::char_type, char>::value), "");
@@ -32,4 +32,6 @@ int main()
     static_assert((std::is_same<std::basic_stringstream<char>::pos_type, std::char_traits<char>::pos_type>::value), "");
     static_assert((std::is_same<std::basic_stringstream<char>::off_type, std::char_traits<char>::off_type>::value), "");
     static_assert((std::is_same<std::basic_stringstream<char>::allocator_type, std::allocator<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/data.pass.cpp b/libcxx/test/std/iterators/iterator.container/data.pass.cpp
index ab80c1cf5ca..952dc687083 100644
--- a/libcxx/test/std/iterators/iterator.container/data.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/data.pass.cpp
@@ -61,7 +61,7 @@ void test_const_array( const T (&array)[Sz] )
     assert ( std::data(array) == &array[0]);
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v; v.push_back(1);
     std::array<int, 1> a; a[0] = 3;
@@ -83,4 +83,6 @@ int main()
 
     static constexpr int arrA [] { 1, 2, 3 };
     test_const_array ( arrA );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp b/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp
index 1cd16ad9a37..08014776c9d 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     int c[5];
     std::empty(c);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp b/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp
index 4ac2e1335ce..153ea13b643 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::vector<int> c;
     std::empty(c);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp b/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp
index dcdd89a3135..5dafb5119fe 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::initializer_list<int> c = { 4 };
     std::empty(c);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.pass.cpp b/libcxx/test/std/iterators/iterator.container/empty.pass.cpp
index b792e006658..5c46cd6fbf0 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.pass.cpp
@@ -60,7 +60,7 @@ void test_const_array( const T (&array)[Sz] )
     assert (!std::empty(array));
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v; v.push_back(1);
     std::list<int>   l; l.push_back(2);
@@ -85,4 +85,6 @@ int main()
 
     static constexpr int arrA [] { 1, 2, 3 };
     test_const_array ( arrA );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/size.pass.cpp b/libcxx/test/std/iterators/iterator.container/size.pass.cpp
index 5b78afa2669..db215b8544f 100644
--- a/libcxx/test/std/iterators/iterator.container/size.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/size.pass.cpp
@@ -63,7 +63,7 @@ void test_const_array( const T (&array)[Sz] )
     assert ( std::size(array) == Sz );
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v; v.push_back(1);
     std::list<int>   l; l.push_back(2);
@@ -87,4 +87,6 @@ int main()
 
     static constexpr int arrA [] { 1, 2, 3 };
     test_const_array ( arrA );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp
index e922a4bfa46..b5929ca8c10 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp
@@ -72,10 +72,12 @@ test5()
     static_assert((std::is_same<typename It::iterator_category, std::input_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test2<A>();
     test3<A>();
     test4<A>();
     test5<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp
index 6382d06c74b..45408056370 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp
@@ -42,7 +42,7 @@ constepxr_test(It i, typename std::iterator_traits<It>::difference_type n, It x)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -68,4 +68,6 @@ int main()
     static_assert( constepxr_test(s+5, -5, s), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp
index 86fcfbc5853..bd1b02a484d 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp
@@ -37,7 +37,7 @@ constexpr_test(It first, It last, typename std::iterator_traits<It>::difference_
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -57,4 +57,6 @@ int main()
     static_assert( constexpr_test(s, s+10, 10), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp
index ad99aed99b5..87f79fbd32b 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp
@@ -51,7 +51,7 @@ constexpr_test(It i, It x)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -83,4 +83,6 @@ int main()
     static_assert( constexpr_test(s, s+1), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp
index b7d99391723..2ee0444ce14 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp
@@ -49,7 +49,7 @@ constexpr_test(It i, It x)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -74,4 +74,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp
index 246aeb5e8bb..5abf59bf3de 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<const A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<It::pointer, const A*>::value), "");
     static_assert((std::is_same<It::reference, const A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp
index 774609e1cc1..358abb619b1 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp
@@ -16,7 +16,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<const volatile A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -24,4 +24,6 @@ int main()
     static_assert((std::is_same<It::pointer, const volatile A*>::value), "");
     static_assert((std::is_same<It::reference, const volatile A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp
index 5c5c07d442d..728909e693c 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp
@@ -63,7 +63,7 @@ struct NotAnIteratorNoCategory
 //     typedef std::forward_iterator_tag iterator_category;
 };
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::iterator_traits<NotAnIteratorEmpty> T;
@@ -118,4 +118,6 @@ int main()
     typedef T::reference         RT; // expected-error-re {{no type named 'reference' in 'std::{{.+}}::iterator_traits<{{.+}}>}}
     typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::{{.+}}::iterator_traits<{{.+}}>}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp
index 81dca5186ec..35fc877f206 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp
@@ -30,8 +30,10 @@ public:
     static const bool value = sizeof(test<T>(0)) == 1;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<not_an_iterator> It;
     static_assert(!(has_value_type<It>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
index 1c8d11eb151..1e4d87c757c 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
@@ -32,7 +32,7 @@ struct test_iterator
     typedef std::forward_iterator_tag iterator_category;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<test_iterator> It;
     static_assert((std::is_same<It::difference_type, int>::value), "");
@@ -40,4 +40,6 @@ int main()
     static_assert((std::is_same<It::pointer, A*>::value), "");
     static_assert((std::is_same<It::reference, A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::forward_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp
index 3be21c49a3b..6016f6d4088 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<It::pointer, A*>::value), "");
     static_assert((std::is_same<It::reference, A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp
index ebcc30075af..035360645dc 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp
@@ -16,7 +16,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<volatile A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -24,4 +24,6 @@ int main()
     static_assert((std::is_same<It::pointer, volatile A*>::value), "");
     static_assert((std::is_same<It::reference, volatile A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp
index 6d7f64b9a1e..8380fb6b4e2 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp
@@ -13,7 +13,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::bidirectional_iterator_tag tag;
     ((void)tag); // Prevent unused warning
@@ -21,4 +21,6 @@ int main()
                                    std::bidirectional_iterator_tag>::value), "");
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::bidirectional_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp
index 753f25c667b..0afdc3eca0a 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp
@@ -13,7 +13,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::forward_iterator_tag tag;
     ((void)tag); // Prevent unused warning
@@ -21,4 +21,6 @@ int main()
                                    std::forward_iterator_tag>::value), "");
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::forward_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp
index ac517dd6785..26de37448d1 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp
@@ -13,10 +13,12 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::input_iterator_tag tag;
     ((void)tag); // Prevent unused warning
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::input_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp
index 1635850cf59..657e6f8ea18 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp
@@ -13,10 +13,12 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::output_iterator_tag tag;
     ((void)tag); // Prevent unused warning
     static_assert((!std::is_base_of<std::input_iterator_tag,
                                     std::output_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp
index da2de468176..5448a671573 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp
@@ -13,7 +13,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::random_access_iterator_tag tag;
     ((void)tag); // Prevent unused warning
@@ -21,4 +21,6 @@ int main()
                                    std::random_access_iterator_tag>::value), "");
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp b/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp
index b87b82f272e..69a27843474 100644
--- a/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp
@@ -40,11 +40,13 @@ namespace Foo {
 }
 
 
-int main(){
+int main(int, char**) {
 // Bug #28927 - shouldn't find these via ADL
     TEST_IGNORE_NODISCARD  std::cbegin (Foo::FakeContainer());
     TEST_IGNORE_NODISCARD  std::cend   (Foo::FakeContainer());
     TEST_IGNORE_NODISCARD  std::crbegin(Foo::FakeContainer());
     TEST_IGNORE_NODISCARD  std::crend  (Foo::FakeContainer());
+
+  return 0;
 }
 #endif
diff --git a/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp b/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp
index a55e0b639d3..7580b463dce 100644
--- a/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp
@@ -135,7 +135,7 @@ void test_const_array( const T (&array)[Sz] ) {
 #endif
     }
 
-int main(){
+int main(int, char**) {
     std::vector<int> v; v.push_back(1);
     std::list<int> l;   l.push_back(2);
     std::array<int, 1> a; a[0] = 3;
@@ -197,4 +197,6 @@ int main(){
         static_assert ( *std::crbegin(c) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp b/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
index a6be18d10ec..09b4d76288c 100644
--- a/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
+++ b/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
@@ -17,4 +17,6 @@ void f(const std::string &s) { TEST_IGNORE_NODISCARD s.begin(); }
 
 void AppendTo(const std::vector<char> &v) { TEST_IGNORE_NODISCARD v.begin(); }
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp
index 1bdd5ddef25..9aad14992f5 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp
@@ -17,7 +17,9 @@
 #include <iterator>
 #include <vector>
 
-int main()
+int main(int, char**)
 {
     std::back_insert_iterator<std::vector<int> > i = std::vector<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp
index 22f16c2eb09..2aad3fa3f48 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp
@@ -23,8 +23,10 @@ test(C c)
     std::back_insert_iterator<C> i(c);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp
index ccb22b2bd3d..d36b1ce0630 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp
@@ -28,8 +28,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp
index acb272b4ced..512eb1e56b3 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp
index 67772dabc57..2b76a27148e 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp
@@ -39,7 +39,9 @@ public:
         {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::vector<Copyable>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp
index 93fe8e5fa33..506b7b6f000 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp
@@ -31,7 +31,9 @@ test(C c)
     assert(c.back() == typename C::value_type());
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<std::unique_ptr<int> >());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp
index b7f11e0f771..460f723a407 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp
index 6c27ce826b2..bd6df64488a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp
@@ -27,8 +27,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
index 47d38438218..470392bc551 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
@@ -52,7 +52,9 @@ test()
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp
index 1ebfd4d3f14..eb3346b2e7a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp
@@ -17,7 +17,9 @@
 #include <iterator>
 #include <list>
 
-int main()
+int main(int, char**)
 {
     std::front_insert_iterator<std::list<int> > i = std::list<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp
index 80307cb1547..2ef4ba87994 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp
@@ -23,8 +23,10 @@ test(C c)
     std::front_insert_iterator<C> i(c);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp
index 9b642a7d24e..7c9b09ffd2a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp
@@ -28,8 +28,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp
index 7aa1d6da6a7..ea5c024105b 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp
index 555b72d7970..5e1a86d57f0 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp
@@ -39,8 +39,10 @@ public:
         {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::list<Copyable>());
     test(nasty_list<Copyable>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp
index ad032a4dde6..450f395d49a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp
@@ -29,7 +29,9 @@ test(C c)
     assert(c.front() == typename C::value_type());
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<std::unique_ptr<int> >());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp
index bf1bf38ad80..3367229b422 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp
index f4cc7c984f1..b7436778d11 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp
@@ -27,8 +27,10 @@ test(C c)
     assert(c.front() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
index c8609efbe41..c65a8e6f68d 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
@@ -53,7 +53,9 @@ test()
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp
index ae45c90f34e..531dac03c9f 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp
@@ -23,8 +23,10 @@ test(C c)
     std::insert_iterator<C> i(c, c.begin());
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp
index 22448fddd61..a3148e2e2a4 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp
@@ -28,8 +28,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp
index c9a8d1ef6e1..99c68609500 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp
index c639a2da169..fe8260b999f 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp
@@ -43,7 +43,7 @@ insert3at(C& c, typename C::iterator i,
     c.insert(++i, x3);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<int> C;
@@ -81,4 +81,6 @@ int main()
     insert3at(c2, c2.begin()+3, 'a', 'b', 'c');
     test(c1, 3, 'a', 'b', 'c', c2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp
index 671d6bd496b..7a5addb1ab0 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp
@@ -52,7 +52,7 @@ struct do_nothing
     void operator()(void*) const {}
 };
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unique_ptr<int, do_nothing> Ptr;
@@ -91,4 +91,6 @@ int main()
     insert3at(c2, c2.begin()+3, Ptr(x+3), Ptr(x+4), Ptr(x+5));
     test(std::move(c1), 3, Ptr(x+3), Ptr(x+4), Ptr(x+5), c2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp
index d531e5fe3ac..8ef0383eed2 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp
index 05ede8a522f..e1ee829bce7 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp
@@ -27,8 +27,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
index 9d58fc40ccb..1e199b3051b 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
@@ -58,7 +58,9 @@ test()
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp
index 36dfddd7f02..3a9b467e06f 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp
@@ -30,7 +30,7 @@ test(It i)
     assert(std::make_move_iterator(i) == r);
 }
 
-int main()
+int main(int, char**)
 {
     {
     char s[] = "1234567890";
@@ -53,4 +53,6 @@ int main()
     static_assert(iter.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp
index 67852259734..e3b881edc9e 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp
@@ -33,7 +33,7 @@ test(It l, It r, typename std::iterator_traits<It>::difference_type x)
     assert(r1 - r2 == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s+5), random_access_iterator<char*>(s), 5);
@@ -49,4 +49,6 @@ int main()
     static_assert( it2 - it1 ==  1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp
index 63c3e8ed5d4..5e1965e19c2 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s+5), 5, random_access_iterator<char*>(s+10));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp
index 95ab190f11a..1e3244e19b9 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -48,4 +48,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp
index 0af1ff83fbf..863e06c0e45 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp
index ce0cb93cff8..3cf76f5daea 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -48,4 +48,6 @@ int main()
     static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp
index f17543335e5..5692f708881 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -45,4 +45,6 @@ int main()
     static_assert(it1 == it2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp
index 1e05a50c7f5..ecf8f90ea1e 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 == r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(input_iterator<char*>(s), input_iterator<char*>(s), true);
@@ -58,4 +58,6 @@ int main()
     static_assert(!(it2 == it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp
index e58a57b5088..3da38b37666 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 > r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), false);
@@ -54,4 +54,6 @@ int main()
     static_assert( (it2 > it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp
index e10962f02cf..dceb4115152 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 >= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), true);
@@ -54,4 +54,6 @@ int main()
     static_assert( (it2 >= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp
index ebe90244e26..675e55f7881 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 < r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), false);
@@ -54,4 +54,6 @@ int main()
     static_assert(!(it2 < it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp
index 72efc481e3f..a2ac0b7a6f7 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 <= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), true);
@@ -54,4 +54,6 @@ int main()
     static_assert(!(it2 <= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp
index 69695e56bbb..01a7195d4d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 != r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(input_iterator<char*>(s), input_iterator<char*>(s), false);
@@ -58,4 +58,6 @@ int main()
     static_assert( (it2 != it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp
index 56b99025eeb..b91767b0814 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp
@@ -29,9 +29,11 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
 
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp
index dae13100db2..7f31920f76a 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp
@@ -34,7 +34,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -52,4 +52,6 @@ int main()
     static_assert(it2.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp
index dfd89df807c..6dfa0d09db9 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp
@@ -27,7 +27,7 @@ test()
     (void)r;
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<char*> >();
     test<forward_iterator<char*> >();
@@ -41,4 +41,6 @@ int main()
     (void)it;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp
index 0b8ea454089..28648b81534 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp
@@ -23,8 +23,10 @@ test(It i)
     std::move_iterator<It> r = i;
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp
index 5832ecbcf80..bed97700e7c 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp
@@ -28,7 +28,7 @@ test(It i)
     assert(r.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(input_iterator<char*>(s));
@@ -44,4 +44,6 @@ int main()
     static_assert(it.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp
index 0b6db37e144..38d52329721 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(bidirectional_iterator<char*>(s+1), bidirectional_iterator<char*>(s));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp
index c7c00183c7c..e98fb6b0936 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(bidirectional_iterator<char*>(s+1), bidirectional_iterator<char*>(s));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp
index f37522c13f6..50597a54b0b 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(input_iterator<char*>(s), input_iterator<char*>(s+1));
@@ -51,4 +51,6 @@ int main()
     static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp
index 4bcbdd5792b..101f5cdbc0f 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(input_iterator<char*>(s), input_iterator<char*>(s+1));
@@ -51,4 +51,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp
index d626ff28a38..ecf3b61058b 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp
@@ -38,7 +38,7 @@ struct do_nothing
     void operator()(void*) const {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         char s[] = "1234567890";
@@ -64,4 +64,6 @@ int main()
     static_assert(it1[5] == '6', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp
index 027162b90f0..6024f99fec3 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp
@@ -27,7 +27,7 @@ test(It i)
     assert(r.operator->() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(s);
@@ -42,4 +42,6 @@ int main()
     static_assert(it2.operator->() == p + 1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp
index 6dfe0a51736..e6e826d8352 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp
@@ -47,7 +47,7 @@ struct do_nothing
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         A a;
@@ -70,4 +70,6 @@ int main()
     static_assert(*it2 == p[1], "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp
index 68fe476ac64..94d012dfb7e 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp
@@ -31,8 +31,10 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp
index fbc5320feb5..84fbccb8be6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp
@@ -37,7 +37,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -56,4 +56,6 @@ int main()
     static_assert(it2.base() == p, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp
index 9eb4669c3c5..905952f42bd 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp
@@ -55,7 +55,7 @@ test()
     static_assert((std::is_same<typename R::iterator_category, typename T::iterator_category>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<char*> >();
     test<forward_iterator<char*> >();
@@ -91,4 +91,6 @@ int main()
         static_assert(std::is_same<It::reference, int&&>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp
index de035fcd3c9..32931eefa91 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp
@@ -27,7 +27,7 @@ test()
     (void)r;
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<const char*> >();
     test<random_access_iterator<char*> >();
@@ -40,4 +40,6 @@ int main()
         (void)it;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp
index bbbf1247f47..6130386b0d2 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp
@@ -23,8 +23,10 @@ test(It i)
     std::reverse_iterator<It> r = i;
 }
 
-int main()
+int main(int, char**)
 {
     const char s[] = "123";
     test(s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp
index 47fc29b094a..32cc74f9586 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp
@@ -28,7 +28,7 @@ test(It i)
     assert(r.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char s[] = "123";
     test(bidirectional_iterator<const char*>(s));
@@ -42,4 +42,6 @@ int main()
         static_assert(it.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp
index 02ab54a5986..5a878e4937e 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp
@@ -29,9 +29,11 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
 
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp
index db53853dc59..53b82bd4038 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp
@@ -34,7 +34,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -50,4 +50,6 @@ int main()
         static_assert(it2.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp
index 8ad3d79b390..fa7026ddeec 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp
@@ -31,7 +31,7 @@ test(It i)
     assert(r.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     random_access_iterator<const char*>b(s);
@@ -46,5 +46,7 @@ int main()
         static_assert(it1.base() == p, "");
     }
 #endif
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp
index c67884d9187..f3e74970967 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 != r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(bidirectional_iterator<const char*>(s), bidirectional_iterator<const char*>(s), false);
@@ -53,4 +53,6 @@ int main()
         static_assert( (it1 != it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp
index 2232a87f5c5..d7658ccfc99 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s));
@@ -49,4 +49,6 @@ int main()
         static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp
index d2337e2086e..edc74fab504 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s));
@@ -50,4 +50,6 @@ int main()
         static_assert(*(++std::make_reverse_iterator(p+2)) == '1', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp
index eed06f3df9c..9b30f59da93 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -48,4 +48,6 @@ int main()
         static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp
index 5460382133c..229f3ca1188 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -45,4 +45,6 @@ int main()
         static_assert(it1 == it2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp
index 35fdf1b1ed8..8b9912c8173 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s+2));
@@ -49,4 +49,6 @@ int main()
         static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp
index f0df91777a7..9ccab06e839 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s+2));
@@ -50,4 +50,6 @@ int main()
         static_assert(*(--std::make_reverse_iterator(p)) == '1', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp
index b59095db8a4..0e3a5d36210 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -48,4 +48,6 @@ int main()
         static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp
index a484a67a7dd..ab92dc0686f 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -45,4 +45,6 @@ int main()
         static_assert(it1 == it2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
index efe3dbf9ccd..820ee006014 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
@@ -43,7 +43,7 @@ test(It i, typename std::iterator_traits<It>::value_type x)
     assert(*r == x);
 }
 
-int main()
+int main(int, char**)
 {
     A a;
     test(&a+1, A());
@@ -58,4 +58,6 @@ int main()
         static_assert(*it2 == p[1], "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp
index 0580eb09813..071e3ef1050 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp
@@ -31,8 +31,10 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp
index e39476a98e9..838bdc917e2 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp
@@ -37,7 +37,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -55,4 +55,6 @@ int main()
         static_assert(it2.base() == p, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp
index 066aa769b37..7bd699bb9ea 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 == r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(bidirectional_iterator<const char*>(s), bidirectional_iterator<const char*>(s), true);
@@ -54,4 +54,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp
index 2c7574eb454..ce901234809 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp
@@ -33,7 +33,7 @@ test(It1 l, It2 r, std::ptrdiff_t x)
     assert((r1 - r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[3] = {0};
     test(random_access_iterator<const char*>(s), random_access_iterator<char*>(s), 0);
@@ -53,4 +53,6 @@ int main()
         static_assert( it2 - it1 == -1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp
index d32932848cf..86b19e3fc6a 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 > r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), false);
@@ -53,4 +53,6 @@ int main()
         static_assert( (it1 > it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp
index b12f7c135d6..de53281202f 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 >= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), true);
@@ -53,4 +53,6 @@ int main()
         static_assert( (it1 >= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp
index a1b08f65c24..bc20d138137 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n,
     assert(rr == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 4, '1');
@@ -45,4 +45,6 @@ int main()
     static_assert(it1[4] == '1', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp
index 7e4f27e7a7c..e49821f833c 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 < r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), false);
@@ -53,4 +53,6 @@ int main()
         static_assert(!(it1 < it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp
index 8934d68efc5..92752361152 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 <= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), true);
@@ -53,4 +53,6 @@ int main()
         static_assert(!(it1 <= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
index ce0b470a612..f16fb2757a5 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
@@ -76,7 +76,7 @@ public:
 
 TEST_CONSTEXPR  C gC;
 
-int main()
+int main(int, char**)
 {
     A a;
     test(&a+1, A());
@@ -115,4 +115,6 @@ int main()
     {
         ((void)gC);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp
index 25876d07267..ba38448515d 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -49,4 +49,6 @@ int main()
         static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp
index 7242f6a347c..11ac625258c 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp
@@ -52,9 +52,11 @@ test()
     static_assert((std::is_same<typename R::iterator_category, typename T::iterator_category>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<char*> >();
     test<random_access_iterator<char*> >();
     test<char*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp
index 4ee68b5fc7a..d6a3b086287 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::istream_iterator<int> io;
@@ -36,4 +36,6 @@ int main()
         j = *i;
         assert(j == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp
index 1ffe4dcfe3c..e2bebbaea10 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp
@@ -19,7 +19,7 @@
 
 struct S { S(); }; // not constexpr
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -28,4 +28,6 @@ int main()
 #else
 #error "C++11 only test"
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp
index f569d3206d8..fa43566ddde 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp
@@ -42,7 +42,7 @@ void operator ()() const {}
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::istream_iterator<int> T;
@@ -61,4 +61,6 @@ int main()
     test_trivial<S>()();
     test_trivial<std::string>()();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp
index 50b40aba48c..a4c47974dae 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -26,4 +26,6 @@ int main()
     int j = 0;
     inf >> j;
     assert(j == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp
index a2862b4031f..5409cc5955b 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp
@@ -29,10 +29,12 @@ std::istream& operator>>(std::istream& is, A& a)
     return is >> a.d_ >> a.i_;
 }
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf("1.5  23 ");
     std::istream_iterator<A> i(inf);
     assert(i->d_ == 1.5);
     assert(i->i_ == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp
index 38ffe4bfd7d..c99e723b041 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -30,4 +30,6 @@ int main()
     assert(j == 23);
     j = *i;
     assert(j == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp
index 5ba335c5edf..616a3ca3852 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp
@@ -22,7 +22,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf1(" 1 23");
     std::istringstream inf2(" 1 23");
@@ -51,4 +51,6 @@ int main()
 
     assert(std::operator==(i1, i2));
     assert(std::operator!=(i1, i3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp
index b32f358cf24..83d206e719b 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -28,4 +28,6 @@ int main()
     j = 0;
     j = *icopy;
     assert(j == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp
index 6a361ff7172..ab61f57f9dc 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -25,4 +25,6 @@ int main()
     int j = 0;
     j = *i;
     assert(j == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp
index 9a7185c1b89..5170b1e5365 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp
@@ -41,7 +41,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::istream_iterator<double> I1; // double is trivially destructible
 #if TEST_STD_VER <= 14
@@ -82,4 +82,6 @@ int main()
     typedef std::istream_iterator<std::string> I3; // string is NOT trivially destructible
     static_assert(!std::is_trivially_copy_constructible<I3>::value, "");
     static_assert(!std::is_trivially_destructible<I3>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp
index d7e1a31e571..9502e0da7b9 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::istreambuf_iterator<char> T;
@@ -41,4 +41,6 @@ int main()
         (void)it2;
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp
index a7927cbb2f0..b51d19a8e5e 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf;
@@ -38,4 +38,6 @@ int main()
         std::istreambuf_iterator<wchar_t> i(inf);
         assert(i != std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp
index 6b4719cadb0..87afe840d03 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -32,4 +32,6 @@ int main()
         assert(i != std::istreambuf_iterator<wchar_t>());
         assert(*i == L'b');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp
index 2b94d8c9756..d92cddde1f1 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istreambuf_iterator<char> i(nullptr);
@@ -46,4 +46,6 @@ int main()
         std::istreambuf_iterator<wchar_t> i(inf.rdbuf());
         assert(i != std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp
index 9b003413161..1fcdf7af146 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf1("abc");
@@ -96,4 +96,6 @@ int main()
         assert( i5.equal(i4));
         assert( i5.equal(i5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp
index 7e50c68f7c1..d4184aa6ce6 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf1("abc");
@@ -98,4 +98,6 @@ int main()
         assert(!(i5 != i4));
         assert(!(i5 != i5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp
index 28cb7a93a4a..d60302ad40d 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -36,4 +36,6 @@ int main()
         ++i;
         assert(*i == L'c');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp
index ede97380bb8..875989f5df5 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf1("abc");
@@ -98,4 +98,6 @@ int main()
         assert( (i5 == i4));
         assert( (i5 == i5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp
index 15c266d7314..e3121494df4 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -34,4 +34,6 @@ int main()
         assert(*i++ == L'c');
         assert(i == std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp
index 148bd725a7f..9d05cbda340 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -35,4 +35,6 @@ int main()
         assert(*++i == L'c');
         assert(++i == std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp
index 2535d991397..74e1813d512 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp
@@ -28,7 +28,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -40,4 +40,6 @@ int main()
         std::istreambuf_iterator<wchar_t> i(inf);
         assert(*i++ == L'a');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp
index 829d1f0a6df..a6c6435f10a 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp
@@ -34,7 +34,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::istreambuf_iterator<char> I1;
     static_assert((std::is_same<I1::iterator_category, std::input_iterator_tag>::value), "");
@@ -65,4 +65,6 @@ int main()
     static_assert((std::is_nothrow_default_constructible<I2>::value), "" );
     static_assert((std::is_trivially_copy_constructible<I2>::value), "" );
     static_assert((std::is_trivially_destructible<I2>::value), "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp
index 3521b05fa8f..8d7500cf292 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp
@@ -13,11 +13,13 @@
 #include <iterator>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     int* i = std::begin(ia);
     assert(*i == 1);
     *i = 2;
     assert(ia[0] == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp
index 255a837e734..06b5e7907e8 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp
@@ -13,10 +13,12 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     const std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
     std::vector<int>::const_iterator i = begin(v);
     assert(*i == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp
index bc99f7a408c..75e61d3b411 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp
@@ -13,7 +13,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
@@ -21,4 +21,6 @@ int main()
     assert(*i == 1);
     *i = 2;
     assert(*i == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp
index 0f21309baab..a6721155afd 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp
@@ -13,11 +13,13 @@
 #include <iterator>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     int* i = std::begin(ia);
     int* e = std::end(ia);
     assert(e == ia + 3);
     assert(e - i == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp
index 45796233202..78a6affd8a2 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp
@@ -13,10 +13,12 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     const std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
     std::vector<int>::const_iterator i = end(v);
     assert(i == v.cend());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp
index 8fa2a4e5600..9970ec922c3 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp
@@ -13,10 +13,12 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
     std::vector<int>::iterator i = end(v);
     assert(i == v.end());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp
index 24cf15ff1be..491f3bc1cec 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp
@@ -16,11 +16,13 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream outf;
     std::ostream_iterator<int> i(outf);
     std::ostream_iterator<int> j = i;
     assert(outf.good());
     ((void)j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp
index 1de0ea2eabe..78abcfab677 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp
@@ -23,7 +23,7 @@ typedef std::basic_ostream<char, MyTraits> BasicStream;
 
 void operator&(BasicStream const&) {}
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -35,4 +35,6 @@ int main()
         std::ostream_iterator<int, char, MyTraits> i(outf);
         assert(outf.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp
index 7b4422f94bd..2c48189f91a 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp
@@ -24,7 +24,7 @@ typedef std::basic_ostream<char, MyTraits> BasicStream;
 
 void operator&(BasicStream const&) {}
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -41,4 +41,6 @@ int main()
         std::ostream_iterator<int, char, MyTraits> i(outf, ", ");
         assert(outf.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
index dea585c3c04..5a2f2cc99f2 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
@@ -26,7 +26,7 @@
 #pragma warning(disable: 4244) // conversion from 'X' to 'Y', possible loss of data
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -52,4 +52,6 @@ int main()
         i = 2.4;
         assert(outf.str() == L"2, ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp
index 4d79f7c1d56..6cb190ab491 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream os;
     std::ostream_iterator<int> i(os);
     std::ostream_iterator<int>& iref = *i;
     assert(&iref == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp
index d93aad6cce5..eedab8115d8 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream os;
     std::ostream_iterator<int> i(os);
@@ -25,4 +25,6 @@ int main()
     assert(&iref1 == &i);
     std::ostream_iterator<int>& iref2 = i++;
     assert(&iref2 == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp
index 716ba2bfdc3..950c7dfe8c0 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::ostream_iterator<double> I1;
 #if TEST_STD_VER <= 14
@@ -54,4 +54,6 @@ int main()
     static_assert((std::is_same<I2::char_type, wchar_t>::value), "");
     static_assert((std::is_same<I2::traits_type, std::char_traits<wchar_t> >::value), "");
     static_assert((std::is_same<I2::ostream_type, std::wostream>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp
index 0c28a77ac16..aa6031a8ad8 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -28,4 +28,6 @@ int main()
         std::ostreambuf_iterator<wchar_t> i(outf);
         assert(!i.failed());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp
index 0d2c85bef84..2c64dc29fdb 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -28,4 +28,6 @@ int main()
         std::ostreambuf_iterator<wchar_t> i(outf.rdbuf());
         assert(!i.failed());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp
index 45e57fc8007..fe51fba1fd5 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -35,4 +35,6 @@ int main()
         i = L'b';
         assert(outf.str() == L"ab");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp
index e33a5a5c8f4..4904320b0a0 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -30,4 +30,6 @@ int main()
         std::ostreambuf_iterator<wchar_t>& iref = *i;
         assert(&iref == &i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
index b52fce81344..fa67513ad6e 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
@@ -25,7 +25,7 @@ struct my_streambuf : public std::basic_streambuf<Char,Traits> {
     int_type sputc(char_type) { return Traits::eof(); }
     };
 
-int main()
+int main(int, char**)
 {
     {
         my_streambuf<char> buf;
@@ -39,4 +39,6 @@ int main()
         i = L'a';
         assert(i.failed());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp
index c765a5c2daa..81ae55ae7a6 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -35,4 +35,6 @@ int main()
         std::ostreambuf_iterator<wchar_t>& iref2 = i++;
         assert(&iref2 == &i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp
index 346d8b8496f..671a09bb7a3 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::ostreambuf_iterator<char> I1;
 #if TEST_STD_VER <= 14
@@ -58,4 +58,6 @@ int main()
     static_assert((std::is_same<I2::traits_type, std::char_traits<wchar_t> >::value), "");
     static_assert((std::is_same<I2::streambuf_type, std::wstreambuf>::value), "");
     static_assert((std::is_same<I2::ostream_type, std::wostream>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cmp/cmp.common/common_comparison_category.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.common/common_comparison_category.pass.cpp
index 4c999637ffb..218291b6b49 100644
--- a/libcxx/test/std/language.support/cmp/cmp.common/common_comparison_category.pass.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.common/common_comparison_category.pass.cpp
@@ -33,7 +33,7 @@ void test_cat() {
 
 // [class.spaceship]p4: The 'common comparison type' U of a possibly-empty list
 //   of 'n' types T0, T1, ..., TN, is defined as follows:
-int main() {
+int main(int, char**) {
   using WE = std::weak_equality;
   using SE = std::strong_equality;
   using PO = std::partial_ordering;
@@ -89,4 +89,6 @@ int main() {
     test_cat<SO, SO>();
     test_cat<SO, SO, SO>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cmp/cmp.partialord/partialord.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.partialord/partialord.pass.cpp
index 6c51b7a208d..f2e673db696 100644
--- a/libcxx/test/std/language.support/cmp/cmp.partialord/partialord.pass.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.partialord/partialord.pass.cpp
@@ -155,9 +155,11 @@ constexpr bool test_constexpr() {
   return true;
 }
 
-int main() {
+int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_conversion(), "conversion test failed");
   static_assert(test_constexpr(), "constexpr test failed");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cmp/cmp.strongeq/cmp.strongeq.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.strongeq/cmp.strongeq.pass.cpp
index e34cadc55ce..a5af910a5e0 100644
--- a/libcxx/test/std/language.support/cmp/cmp.strongeq/cmp.strongeq.pass.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.strongeq/cmp.strongeq.pass.cpp
@@ -87,9 +87,11 @@ constexpr bool test_constexpr() {
   return true;
 }
 
-int main() {
+int main(int, char**) {
   test_static_members();
   test_signatures();
   test_conversion();
   static_assert(test_constexpr(), "constexpr test failed");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cmp/cmp.strongord/strongord.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.strongord/strongord.pass.cpp
index 4b75e5d51ef..a31fd34d4f1 100644
--- a/libcxx/test/std/language.support/cmp/cmp.strongord/strongord.pass.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.strongord/strongord.pass.cpp
@@ -203,9 +203,11 @@ constexpr bool test_constexpr() {
   return true;
 }
 
-int main() {
+int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_conversion(), "conversion test failed");
   static_assert(test_constexpr(), "constexpr test failed");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cmp/cmp.weakeq/cmp.weakeq.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.weakeq/cmp.weakeq.pass.cpp
index dae2f214717..367aac6bebe 100644
--- a/libcxx/test/std/language.support/cmp/cmp.weakeq/cmp.weakeq.pass.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.weakeq/cmp.weakeq.pass.cpp
@@ -62,8 +62,10 @@ constexpr bool test_constexpr() {
   return true;
 }
 
-int main() {
+int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_constexpr(), "constexpr test failed");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp
index 6e9e7d44106..ada8d240b6d 100644
--- a/libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp
@@ -160,9 +160,11 @@ constexpr bool test_constexpr() {
   return true;
 }
 
-int main() {
+int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_conversion(), "conversion test failed");
   static_assert(test_constexpr(), "constexpr test failed");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/cstdint/cstdint.syn/cstdint.pass.cpp b/libcxx/test/std/language.support/cstdint/cstdint.syn/cstdint.pass.cpp
index 6f46342da94..ec4afd7f69d 100644
--- a/libcxx/test/std/language.support/cstdint/cstdint.syn/cstdint.pass.cpp
+++ b/libcxx/test/std/language.support/cstdint/cstdint.syn/cstdint.pass.cpp
@@ -18,7 +18,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     // typedef std::int8_t
     static_assert(sizeof(std::int8_t)*CHAR_BIT == 8,
@@ -288,4 +288,6 @@ int main()
 #ifndef UINTMAX_C
 #error UINTMAX_C not defined
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/align_val_t.pass.cpp b/libcxx/test/std/language.support/support.dynamic/align_val_t.pass.cpp
index 1b0b4c00baa..6e65518233a 100644
--- a/libcxx/test/std/language.support/support.dynamic/align_val_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/align_val_t.pass.cpp
@@ -14,7 +14,7 @@
 
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   {
     static_assert(std::is_enum<std::align_val_t>::value, "");
     static_assert(std::is_same<std::underlying_type<std::align_val_t>::type, std::size_t>::value, "");
@@ -30,4 +30,6 @@ int main() {
     static_assert(b == std::align_val_t(32), "");
     static_assert(static_cast<std::size_t>(c) == (std::size_t)-1, "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/alloc.errors/bad.alloc/bad_alloc.pass.cpp b/libcxx/test/std/language.support/support.dynamic/alloc.errors/bad.alloc/bad_alloc.pass.cpp
index 713e66245c0..f0b2bd21fec 100644
--- a/libcxx/test/std/language.support/support.dynamic/alloc.errors/bad.alloc/bad_alloc.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/alloc.errors/bad.alloc/bad_alloc.pass.cpp
@@ -12,7 +12,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_alloc>::value),
                  "std::is_base_of<std::exception, std::bad_alloc>::value");
@@ -23,4 +23,6 @@ int main()
     b2 = b;
     const char* w = b2.what();
     assert(w);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.badlength/bad_array_new_length.pass.cpp b/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.badlength/bad_array_new_length.pass.cpp
index d2fefdd1b94..35fd1304125 100644
--- a/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.badlength/bad_array_new_length.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.badlength/bad_array_new_length.pass.cpp
@@ -12,7 +12,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::bad_alloc, std::bad_array_new_length>::value),
                   "std::is_base_of<std::bad_alloc, std::bad_array_new_length>::value");
@@ -23,4 +23,6 @@ int main()
     b2 = b;
     const char* w = b2.what();
     assert(w);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.handler/new_handler.pass.cpp b/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.handler/new_handler.pass.cpp
index f5681d8d92f..b69fe15232c 100644
--- a/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.handler/new_handler.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/alloc.errors/new.handler/new_handler.pass.cpp
@@ -14,9 +14,11 @@
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::new_handler, void(*)()>::value), "");
     std::new_handler p = f;
     assert(p == &f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/alloc.errors/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/support.dynamic/alloc.errors/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.dynamic/alloc.errors/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/alloc.errors/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/get_new_handler.pass.cpp b/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/get_new_handler.pass.cpp
index 922ab9db49c..a9ed3b0cf36 100644
--- a/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/get_new_handler.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/get_new_handler.pass.cpp
@@ -14,11 +14,13 @@
 void f1() {}
 void f2() {}
 
-int main()
+int main(int, char**)
 {
     assert(std::get_new_handler() == 0);
     std::set_new_handler(f1);
     assert(std::get_new_handler() == f1);
     std::set_new_handler(f2);
     assert(std::get_new_handler() == f2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/set_new_handler.pass.cpp b/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/set_new_handler.pass.cpp
index 37c477f1312..cff382b0ee3 100644
--- a/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/set_new_handler.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/alloc.errors/set.new.handler/set_new_handler.pass.cpp
@@ -14,8 +14,10 @@
 void f1() {}
 void f2() {}
 
-int main()
+int main(int, char**)
 {
     assert(std::set_new_handler(f1) == 0);
     assert(std::set_new_handler(f2) == f1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/delete_align_val_t_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/delete_align_val_t_replace.pass.cpp
index de09a75557a..0a5265861b6 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/delete_align_val_t_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/delete_align_val_t_replace.pass.cpp
@@ -83,7 +83,7 @@ void operator delete [] (void* p, std::align_val_t) TEST_NOEXCEPT
 struct alignas(OverAligned) A {};
 struct alignas(std::max_align_t) B {};
 
-int main()
+int main(int, char**)
 {
     reset();
     {
@@ -113,4 +113,6 @@ int main()
         assert(0 == unsized_delete_nothrow_called);
         assert(1 == aligned_delete_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t.pass.cpp
index bd99495e573..e303c820847 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t.pass.cpp
@@ -90,7 +90,7 @@ void test_throw_max_size() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new A[2];
@@ -103,4 +103,6 @@ int main()
     {
         test_throw_max_size();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow.pass.cpp
index a8367876903..ed7a53743f0 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow.pass.cpp
@@ -92,7 +92,7 @@ void test_max_alloc() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new(std::nothrow) A[3];
@@ -105,4 +105,6 @@ int main()
     {
         test_max_alloc();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow_replace.pass.cpp
index 5fbcc5ce753..49aa2bce3ea 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow_replace.pass.cpp
@@ -86,7 +86,7 @@ void  operator delete[](void* p, std::align_val_t a) TEST_NOEXCEPT
     --new_called;
 }
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new (std::nothrow) A[2];
@@ -106,4 +106,6 @@ int main()
         assert(!new_called);
         assert(!B_constructed);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_replace.pass.cpp
index 40ba48dec53..cb9a2ef7f6c 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_replace.pass.cpp
@@ -66,7 +66,7 @@ void  operator delete[](void* p, std::align_val_t) TEST_NOEXCEPT
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new A[3];
@@ -85,4 +85,6 @@ int main()
         delete [] bp;
         assert(!new_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array.pass.cpp
index 8365b053c5d..55dc5c75334 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array.pass.cpp
@@ -34,7 +34,7 @@ struct A
     ~A() {--A_constructed;}
 };
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     std::set_new_handler(my_new_handler);
@@ -60,4 +60,6 @@ int main()
     delete [] ap;
     DoNotOptimize(ap);
     assert(A_constructed == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow.pass.cpp
index 3effc7ea3ec..b4d8aa34986 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow.pass.cpp
@@ -34,7 +34,7 @@ struct A
     ~A() {--A_constructed;}
 };
 
-int main()
+int main(int, char**)
 {
     std::set_new_handler(my_new_handler);
 #ifndef TEST_HAS_NO_EXCEPTIONS
@@ -59,4 +59,6 @@ int main()
     delete [] ap;
     DoNotOptimize(ap);
     assert(A_constructed == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow_replace.pass.cpp
index a28f7f4f153..4d90aa9a3fe 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_nothrow_replace.pass.cpp
@@ -43,7 +43,7 @@ struct A
     ~A() {--A_constructed;}
 };
 
-int main()
+int main(int, char**)
 {
     A *ap = new (std::nothrow) A[3];
     DoNotOptimize(ap);
@@ -54,4 +54,6 @@ int main()
     DoNotOptimize(ap);
     assert(A_constructed == 0);
     assert(!new_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_replace.pass.cpp
index 4ea28241c07..e705fc3b499 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_array_replace.pass.cpp
@@ -44,7 +44,7 @@ struct A
     ~A() {--A_constructed;}
 };
 
-int main()
+int main(int, char**)
 {
     A *ap = new A[3];
     DoNotOptimize(ap);
@@ -55,4 +55,6 @@ int main()
     DoNotOptimize(ap);
     assert(A_constructed == 0);
     assert(new_called == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size.sh.cpp
index 482a27e9cf6..a04ceb6ad42 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size.sh.cpp
@@ -19,7 +19,9 @@
 
 #include <new>
 
-int main ()
+int main(int, char**)
 {
     ::operator new[](4);  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align.sh.cpp
index 6183c0c2ce3..e2a61591ad2 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align.sh.cpp
@@ -19,7 +19,9 @@
 
 #include <new>
 
-int main ()
+int main(int, char**)
 {
     ::operator new[](4, std::align_val_t{4});  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align_nothrow.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align_nothrow.sh.cpp
index 1f39219090b..5ad81863d4d 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align_nothrow.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_align_nothrow.sh.cpp
@@ -19,7 +19,9 @@
 
 #include <new>
 
-int main ()
+int main(int, char**)
 {
     ::operator new[](4, std::align_val_t{4}, std::nothrow);  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_nothrow.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_nothrow.sh.cpp
index 39de421c283..53af2c764c0 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_nothrow.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/new_size_nothrow.sh.cpp
@@ -19,7 +19,9 @@
 
 #include <new>
 
-int main ()
+int main(int, char**)
 {
     ::operator new[](4, std::nothrow);  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array11.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array11.pass.cpp
index 686ef66bab8..e1a545cc983 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array11.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array11.pass.cpp
@@ -54,7 +54,7 @@ void operator delete[](void* p, std::size_t) TEST_NOEXCEPT
 //   selected.
 struct A { ~A() {} };
 
-int main()
+int main(int, char**)
 {
 
     A* x = new A[3];
@@ -66,4 +66,6 @@ int main()
     assert(1 == unsized_delete_called);
     assert(0 == sized_delete_called);
     assert(0 == unsized_delete_nothrow_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp
index 773a9b9928d..d69c28be72b 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp
@@ -59,7 +59,7 @@ void operator delete[](void* p, std::size_t) TEST_NOEXCEPT
 //   selected.
 struct A { ~A() {} };
 
-int main()
+int main(int, char**)
 {
     A* x = new A[3];
     assert(0 == unsized_delete_called);
@@ -70,4 +70,6 @@ int main()
     assert(0 == unsized_delete_called);
     assert(0 == unsized_delete_nothrow_called);
     assert(1 == sized_delete_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_calls_unsized_delete_array.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_calls_unsized_delete_array.pass.cpp
index 2d845e6010d..026250daeee 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_calls_unsized_delete_array.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_calls_unsized_delete_array.pass.cpp
@@ -45,7 +45,7 @@ void operator delete[](void* p, const std::nothrow_t&) TEST_NOEXCEPT
 //   selected.
 struct A { ~A() {} };
 
-int main()
+int main(int, char**)
 {
     A *x = new A[3];
     DoNotOptimize(x);
@@ -56,4 +56,6 @@ int main()
     DoNotOptimize(x);
     assert(1 == delete_called);
     assert(0 == delete_nothrow_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_fsizeddeallocation.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_fsizeddeallocation.sh.cpp
index a077fb7cec6..41739c0ccdc 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_fsizeddeallocation.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array_fsizeddeallocation.sh.cpp
@@ -73,7 +73,7 @@ void operator delete[](void* p, std::size_t) TEST_NOEXCEPT
 //   selected.
 struct A { ~A() {} };
 
-int main()
+int main(int, char**)
 {
     A* x = new A[3];
     assert(0 == unsized_delete_called);
@@ -84,4 +84,6 @@ int main()
     assert(0 == unsized_delete_called);
     assert(0 == unsized_delete_nothrow_called);
     assert(1 == sized_delete_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.dataraces/not_testable.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.dataraces/not_testable.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.dataraces/not_testable.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.dataraces/not_testable.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new.pass.cpp
index 3cd5e12458f..8256b93185d 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new.pass.cpp
@@ -19,11 +19,13 @@ struct A
     ~A() {--A_constructed;}
 };
 
-int main()
+int main(int, char**)
 {
     char buf[sizeof(A)];
 
     A* ap = new(buf) A;
     assert((char*)ap == buf);
     assert(A_constructed == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array.pass.cpp
index 671a3cc050f..8a78df6bffb 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array.pass.cpp
@@ -19,7 +19,7 @@ struct A
     ~A() {--A_constructed;}
 };
 
-int main()
+int main(int, char**)
 {
     const std::size_t Size = 3;
     // placement new might require additional space.
@@ -30,4 +30,6 @@ int main()
     assert((char*)ap >= buf);
     assert((char*)ap < (buf + ExtraSize));
     assert(A_constructed == Size);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array_ptr.fail.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array_ptr.fail.cpp
index b7b17e196e8..4cba717dba8 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array_ptr.fail.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_array_ptr.fail.cpp
@@ -18,8 +18,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     char buffer[100];
     ::operator new[](4, buffer);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_ptr.fail.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_ptr.fail.cpp
index 7b5eb19d92c..05a9b244c1e 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_ptr.fail.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.placement/new_ptr.fail.cpp
@@ -18,8 +18,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     char buffer[100];
     ::operator new(4, buffer);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/delete_align_val_t_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/delete_align_val_t_replace.pass.cpp
index 63e797480b1..22abcba0522 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/delete_align_val_t_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/delete_align_val_t_replace.pass.cpp
@@ -82,7 +82,7 @@ void operator delete(void* p, std::align_val_t) TEST_NOEXCEPT
 struct alignas(OverAligned) A {};
 struct alignas(std::max_align_t) B {};
 
-int main()
+int main(int, char**)
 {
     reset();
     {
@@ -112,4 +112,6 @@ int main()
         assert(0 == unsized_delete_nothrow_called);
         assert(1 == aligned_delete_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new.pass.cpp
index 3c73738d6fd..448da171790 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new.pass.cpp
@@ -34,7 +34,7 @@ struct A
     ~A() {A_constructed = false;}
 };
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     std::set_new_handler(my_new_handler);
@@ -58,4 +58,6 @@ int main()
     assert(A_constructed);
     delete ap;
     assert(!A_constructed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t.pass.cpp
index d0d4b98aee4..0d96db5de48 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t.pass.cpp
@@ -90,7 +90,7 @@ void test_throw_max_size() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new A;
@@ -103,4 +103,6 @@ int main()
     {
         test_throw_max_size();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow.pass.cpp
index d0990c0586b..4b621f78a72 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow.pass.cpp
@@ -92,7 +92,7 @@ void test_max_alloc() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new(std::nothrow) A;
@@ -105,4 +105,6 @@ int main()
     {
         test_max_alloc();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow_replace.pass.cpp
index fa8dc13cf64..892eac20582 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow_replace.pass.cpp
@@ -88,7 +88,7 @@ void  operator delete(void* p, std::align_val_t a) TEST_NOEXCEPT
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new (std::nothrow) A;
@@ -108,4 +108,6 @@ int main()
         assert(!new_called);
         assert(!B_constructed);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_replace.pass.cpp
index d37ca28f03b..32c27d5899e 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_replace.pass.cpp
@@ -66,7 +66,7 @@ void  operator delete(void* p, std::align_val_t) TEST_NOEXCEPT
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         A* ap = new A;
@@ -85,4 +85,6 @@ int main()
         delete bp;
         assert(!new_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow.pass.cpp
index 6d391645f11..dfdf7d77e80 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow.pass.cpp
@@ -34,7 +34,7 @@ struct A
     ~A() {A_constructed = false;}
 };
 
-int main()
+int main(int, char**)
 {
     std::set_new_handler(my_new_handler);
 #ifndef TEST_HAS_NO_EXCEPTIONS
@@ -56,4 +56,6 @@ int main()
     assert(A_constructed);
     delete ap;
     assert(!A_constructed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow_replace.pass.cpp
index b4217525fe6..1f186d8b3d1 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_nothrow_replace.pass.cpp
@@ -43,7 +43,7 @@ struct A
     ~A() {A_constructed = false;}
 };
 
-int main()
+int main(int, char**)
 {
     A *ap = new (std::nothrow) A;
     DoNotOptimize(ap);
@@ -54,4 +54,6 @@ int main()
     DoNotOptimize(ap);
     assert(!A_constructed);
     assert(!new_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_replace.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_replace.pass.cpp
index 300843b2fa0..4854c2fb776 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_replace.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_replace.pass.cpp
@@ -42,7 +42,7 @@ struct A
     ~A() {A_constructed = false;}
 };
 
-int main()
+int main(int, char**)
 {
     A *ap = new A;
     DoNotOptimize(ap);
@@ -53,4 +53,6 @@ int main()
     DoNotOptimize(ap);
     assert(!A_constructed);
     assert(!new_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size.fail.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size.fail.cpp
index 5042a8d1e49..4769933d399 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size.fail.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size.fail.cpp
@@ -18,7 +18,9 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     ::operator new(4);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align.sh.cpp
index e22ea0fdd20..a0d99c76d07 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align.sh.cpp
@@ -19,7 +19,9 @@
 
 #include <new>
 
-int main ()
+int main(int, char**)
 {
     ::operator new(4, std::align_val_t{4});  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align_nothrow.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align_nothrow.sh.cpp
index 617eeae3cfd..54b25ac5589 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align_nothrow.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_align_nothrow.sh.cpp
@@ -19,7 +19,9 @@
 
 #include <new>
 
-int main ()
+int main(int, char**)
 {
     ::operator new(4, std::align_val_t{4}, std::nothrow);  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_nothrow.fail.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_nothrow.fail.cpp
index dd51ad54af9..a0bfa8b7f92 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_nothrow.fail.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/new_size_nothrow.fail.cpp
@@ -18,7 +18,9 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     ::operator new(4, std::nothrow);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete11.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete11.pass.cpp
index 779d7b2acfe..69f8bce2767 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete11.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete11.pass.cpp
@@ -43,7 +43,7 @@ void operator delete(void* p, std::size_t) TEST_NOEXCEPT
     std::free(p);
 }
 
-int main()
+int main(int, char**)
 {
     int *x = new int(42);
     DoNotOptimize(x);
@@ -56,4 +56,6 @@ int main()
     assert(1 == unsized_delete_called);
     assert(0 == sized_delete_called);
     assert(0 == unsized_delete_nothrow_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp
index bed5cc2323a..deb17d1ae74 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp
@@ -48,7 +48,7 @@ void operator delete(void* p, std::size_t) TEST_NOEXCEPT
     std::free(p);
 }
 
-int main()
+int main(int, char**)
 {
     int *x = new int(42);
     DoNotOptimize(x);
@@ -61,4 +61,6 @@ int main()
     assert(0 == unsized_delete_called);
     assert(1 == sized_delete_called);
     assert(0 == unsized_delete_nothrow_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_calls_unsized_delete.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_calls_unsized_delete.pass.cpp
index 9c54750bde1..fbc9cf070bc 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_calls_unsized_delete.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_calls_unsized_delete.pass.cpp
@@ -34,7 +34,7 @@ void operator delete(void* p, const std::nothrow_t&) TEST_NOEXCEPT
     std::free(p);
 }
 
-int main()
+int main(int, char**)
 {
     int *x = new int(42);
     DoNotOptimize(x);
@@ -45,4 +45,6 @@ int main()
     DoNotOptimize(x);
     assert(1 == delete_called);
     assert(0 == delete_nothrow_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_fsizeddeallocation.sh.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_fsizeddeallocation.sh.cpp
index be208b43165..3d62040cbe8 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_fsizeddeallocation.sh.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete_fsizeddeallocation.sh.cpp
@@ -61,7 +61,7 @@ void operator delete(void* p, std::size_t) TEST_NOEXCEPT
     std::free(p);
 }
 
-int main()
+int main(int, char**)
 {
     int *x = new int(42);
     DoNotOptimize(x);
@@ -74,4 +74,6 @@ int main()
     assert(1 == sized_delete_called);
     assert(0 == unsized_delete_called);
     assert(0 == unsized_delete_nothrow_called);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.nodiscard.fail.cpp b/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.nodiscard.fail.cpp
index 3f105410bad..e7252395d35 100644
--- a/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.nodiscard.fail.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.nodiscard.fail.cpp
@@ -19,8 +19,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     int *p = nullptr;
     std::launder(p);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.pass.cpp b/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.pass.cpp
index c3d2271834f..f9d4da37146 100644
--- a/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.pass.cpp
@@ -20,7 +20,7 @@
 constexpr int gi = 5;
 constexpr float gf = 8.f;
 
-int main() {
+int main(int, char**) {
     static_assert(std::launder(&gi) == &gi, "" );
     static_assert(std::launder(&gf) == &gf, "" );
 
@@ -31,4 +31,6 @@ int main() {
 
     assert(std::launder(i) == i);
     assert(std::launder(f) == f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.types.fail.cpp b/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.types.fail.cpp
index f8fd12f1cda..d97d00194e2 100644
--- a/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.types.fail.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/ptr.launder/launder.types.fail.cpp
@@ -21,7 +21,7 @@
 
 void foo() {}
 
-int main ()
+int main(int, char**)
 {
     void *p = nullptr;
     (void) std::launder((               void *) nullptr);
@@ -32,4 +32,6 @@ int main ()
 
     (void) std::launder(foo);                              // expected-error-re@new:* 1 {{static_assert failed{{.*}} "can't launder functions"}}
     // expected-error@new:* 0-1 {{function pointer argument to '__builtin_launder' is not allowed}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/bad.exception/bad_exception.pass.cpp b/libcxx/test/std/language.support/support.exception/bad.exception/bad_exception.pass.cpp
index c4e1cc7a1ab..e5f4fbe6dcf 100644
--- a/libcxx/test/std/language.support/support.exception/bad.exception/bad_exception.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/bad.exception/bad_exception.pass.cpp
@@ -12,7 +12,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_exception>::value),
                  "std::is_base_of<std::exception, std::bad_exception>::value");
@@ -23,4 +23,6 @@ int main()
     b2 = b;
     const char* w = b2.what();
     assert(w);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/except.nested/assign.pass.cpp b/libcxx/test/std/language.support/support.exception/except.nested/assign.pass.cpp
index c03f4bbfd4f..972649579b1 100644
--- a/libcxx/test/std/language.support/support.exception/except.nested/assign.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/except.nested/assign.pass.cpp
@@ -26,7 +26,7 @@ public:
     friend bool operator==(const A& x, const A& y) {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::nested_exception e0;
@@ -59,4 +59,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/except.nested/ctor_copy.pass.cpp b/libcxx/test/std/language.support/support.exception/except.nested/ctor_copy.pass.cpp
index cc8c9985622..9d65f5fb22b 100644
--- a/libcxx/test/std/language.support/support.exception/except.nested/ctor_copy.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/except.nested/ctor_copy.pass.cpp
@@ -26,7 +26,7 @@ public:
     friend bool operator==(const A& x, const A& y) {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::nested_exception e0;
@@ -57,4 +57,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/except.nested/ctor_default.pass.cpp b/libcxx/test/std/language.support/support.exception/except.nested/ctor_default.pass.cpp
index 5aa762cf7ca..a96c3d015a1 100644
--- a/libcxx/test/std/language.support/support.exception/except.nested/ctor_default.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/except.nested/ctor_default.pass.cpp
@@ -26,7 +26,7 @@ public:
     friend bool operator==(const A& x, const A& y) {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::nested_exception e;
@@ -55,4 +55,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp b/libcxx/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp
index 426ea55bff9..01ef7ade7c2 100644
--- a/libcxx/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp
@@ -56,7 +56,7 @@ class E1 : public std::nested_exception {};
 class E2 : public std::nested_exception {};
 class E : public E1, public E2 {};
 
-int main()
+int main(int, char**)
 {
     {
         try
@@ -131,4 +131,6 @@ int main()
         }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/except.nested/rethrow_nested.pass.cpp b/libcxx/test/std/language.support/support.exception/except.nested/rethrow_nested.pass.cpp
index ba81b8fe3af..204c3b567e7 100644
--- a/libcxx/test/std/language.support/support.exception/except.nested/rethrow_nested.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/except.nested/rethrow_nested.pass.cpp
@@ -31,7 +31,7 @@ void go_quietly()
     std::exit(0);
 }
 
-int main()
+int main(int, char**)
 {
     {
         try
@@ -67,4 +67,6 @@ int main()
             assert(false);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/except.nested/throw_with_nested.pass.cpp b/libcxx/test/std/language.support/support.exception/except.nested/throw_with_nested.pass.cpp
index c0bc423b01b..b63053c3304 100644
--- a/libcxx/test/std/language.support/support.exception/except.nested/throw_with_nested.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/except.nested/throw_with_nested.pass.cpp
@@ -42,7 +42,7 @@ public:
 struct Final final {};
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         try
@@ -128,4 +128,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/exception.terminate/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/support.exception/exception.terminate/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.exception/exception.terminate/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/exception.terminate/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/get_terminate.pass.cpp b/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/get_terminate.pass.cpp
index 2ec624ba654..851d93bc0c8 100644
--- a/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/get_terminate.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/get_terminate.pass.cpp
@@ -15,10 +15,12 @@
 void f1() {}
 void f2() {}
 
-int main()
+int main(int, char**)
 {
     std::set_terminate(f1);
     assert(std::get_terminate() == f1);
     std::set_terminate(f2);
     assert(std::get_terminate() == f2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/set_terminate.pass.cpp b/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/set_terminate.pass.cpp
index 9eae3a45edf..e4464b9afc1 100644
--- a/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/set_terminate.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/exception.terminate/set.terminate/set_terminate.pass.cpp
@@ -15,8 +15,10 @@
 void f1() {}
 void f2() {}
 
-int main()
+int main(int, char**)
 {
     std::set_terminate(f1);
     assert(std::set_terminate(f2) == f1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/exception.terminate/terminate.handler/terminate_handler.pass.cpp b/libcxx/test/std/language.support/support.exception/exception.terminate/terminate.handler/terminate_handler.pass.cpp
index 8f889beee8f..2519f0bc9ce 100644
--- a/libcxx/test/std/language.support/support.exception/exception.terminate/terminate.handler/terminate_handler.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/exception.terminate/terminate.handler/terminate_handler.pass.cpp
@@ -14,9 +14,11 @@
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::terminate_handler, void(*)()>::value), "");
     std::terminate_handler p = f;
     assert(p == &f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/exception.terminate/terminate/terminate.pass.cpp b/libcxx/test/std/language.support/support.exception/exception.terminate/terminate/terminate.pass.cpp
index 431ad8bf943..4243fb5cadf 100644
--- a/libcxx/test/std/language.support/support.exception/exception.terminate/terminate/terminate.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/exception.terminate/terminate/terminate.pass.cpp
@@ -17,9 +17,11 @@ void f1()
     std::exit(0);
 }
 
-int main()
+int main(int, char**)
 {
     std::set_terminate(f1);
     std::terminate();
     assert(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/exception/exception.pass.cpp b/libcxx/test/std/language.support/support.exception/exception/exception.pass.cpp
index bfb27418f53..893a7d5b363 100644
--- a/libcxx/test/std/language.support/support.exception/exception/exception.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/exception/exception.pass.cpp
@@ -12,7 +12,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_polymorphic<std::exception>::value,
                  "std::is_polymorphic<std::exception>::value");
@@ -21,4 +21,6 @@ int main()
     b2 = b;
     const char* w = b2.what();
     assert(w);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/propagation/current_exception.pass.cpp b/libcxx/test/std/language.support/support.exception/propagation/current_exception.pass.cpp
index 3c265d8bb88..c95368163d4 100644
--- a/libcxx/test/std/language.support/support.exception/propagation/current_exception.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/propagation/current_exception.pass.cpp
@@ -29,7 +29,7 @@ struct A
 
 int A::constructed = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::exception_ptr p = std::current_exception();
@@ -270,4 +270,6 @@ int main()
         assert(p != nullptr);
     }
     assert(A::constructed == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/propagation/exception_ptr.pass.cpp b/libcxx/test/std/language.support/support.exception/propagation/exception_ptr.pass.cpp
index 39f2d6014dc..164e7774be9 100644
--- a/libcxx/test/std/language.support/support.exception/propagation/exception_ptr.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/propagation/exception_ptr.pass.cpp
@@ -15,7 +15,7 @@
 #include <exception>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::exception_ptr p;
     assert(p == nullptr);
@@ -30,4 +30,6 @@ int main()
     assert(p3 == nullptr);
     p3 = nullptr;
     assert(p3 == nullptr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.pass.cpp b/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.pass.cpp
index 3db951d281f..b26212fd136 100644
--- a/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::constructed = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::exception_ptr p = std::make_exception_ptr(A(5));
@@ -52,4 +52,6 @@ int main()
         assert(A::constructed == 0);
     }
     assert(A::constructed == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/propagation/rethrow_exception.pass.cpp b/libcxx/test/std/language.support/support.exception/propagation/rethrow_exception.pass.cpp
index ab2df72e8e8..015dbef224f 100644
--- a/libcxx/test/std/language.support/support.exception/propagation/rethrow_exception.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/propagation/rethrow_exception.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::constructed = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::exception_ptr p;
@@ -60,4 +60,6 @@ int main()
         assert(A::constructed == 0);
     }
     assert(A::constructed == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exception.pass.cpp b/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exception.pass.cpp
index 29087eb153f..61cfc8f11c1 100644
--- a/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exception.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exception.pass.cpp
@@ -29,7 +29,7 @@ struct B
     }
 };
 
-int main()
+int main(int, char**)
 {
     try
     {
@@ -42,4 +42,6 @@ int main()
         assert(!std::uncaught_exception());
     }
     assert(!std::uncaught_exception());
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exceptions.pass.cpp b/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exceptions.pass.cpp
index bab33d837e5..c25e4d2e069 100644
--- a/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exceptions.pass.cpp
+++ b/libcxx/test/std/language.support/support.exception/uncaught/uncaught_exceptions.pass.cpp
@@ -41,7 +41,7 @@ struct Outer {
     int d_;
 };
 
-int main () {
+int main(int, char**) {
     assert(std::uncaught_exceptions() == 0);
     {
     Outer o(0);
@@ -58,4 +58,6 @@ int main () {
         }
     }
     assert(std::uncaught_exceptions() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.general/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/support.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/support.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.initlist/include_cxx03.pass.cpp b/libcxx/test/std/language.support/support.initlist/include_cxx03.pass.cpp
index 343da95f406..282636ed05b 100644
--- a/libcxx/test/std/language.support/support.initlist/include_cxx03.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/include_cxx03.pass.cpp
@@ -12,6 +12,8 @@
 
 #include <initializer_list>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp b/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp
index ff532fbf267..097f21a5c69 100644
--- a/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/support.initlist.access/access.pass.cpp
@@ -51,11 +51,13 @@ struct B
 
 #endif  // TEST_STD_VER > 11
 
-int main()
+int main(int, char**)
 {
     A test1 = {3, 2, 1};
 #if TEST_STD_VER > 11
     constexpr B test2 = {3, 2, 1};
     (void)test2;
 #endif  // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.initlist/support.initlist.cons/default.pass.cpp b/libcxx/test/std/language.support/support.initlist/support.initlist.cons/default.pass.cpp
index dc5c5ffd47a..8d2e0a7e713 100644
--- a/libcxx/test/std/language.support/support.initlist/support.initlist.cons/default.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/support.initlist.cons/default.pass.cpp
@@ -19,7 +19,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     std::initializer_list<A> il;
     assert(il.size() == 0);
@@ -28,4 +28,6 @@ int main()
     constexpr std::initializer_list<A> il2;
     static_assert(il2.size() == 0, "");
 #endif  // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp b/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp
index 61bf2708441..ec755bfeb98 100644
--- a/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/support.initlist.range/begin_end.pass.cpp
@@ -49,11 +49,13 @@ struct B
 
 #endif  // TEST_STD_VER > 11
 
-int main()
+int main(int, char**)
 {
     A test1 = {3, 2, 1};
 #if TEST_STD_VER > 11
     constexpr B test2 = {3, 2, 1};
     (void)test2;
 #endif  // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.initlist/types.pass.cpp b/libcxx/test/std/language.support/support.initlist/types.pass.cpp
index 9aad9b3f757..1b48980a240 100644
--- a/libcxx/test/std/language.support/support.initlist/types.pass.cpp
+++ b/libcxx/test/std/language.support/support.initlist/types.pass.cpp
@@ -25,7 +25,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::initializer_list<A>::value_type, A>::value), "");
     static_assert((std::is_same<std::initializer_list<A>::reference, const A&>::value), "");
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<std::initializer_list<A>::size_type, std::size_t>::value), "");
     static_assert((std::is_same<std::initializer_list<A>::iterator, const A*>::value), "");
     static_assert((std::is_same<std::initializer_list<A>::const_iterator, const A*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/c.limits/cfloat.pass.cpp b/libcxx/test/std/language.support/support.limits/c.limits/cfloat.pass.cpp
index ec144a03177..12b80adf011 100644
--- a/libcxx/test/std/language.support/support.limits/c.limits/cfloat.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/c.limits/cfloat.pass.cpp
@@ -178,6 +178,8 @@
 #endif
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/c.limits/climits.pass.cpp b/libcxx/test/std/language.support/support.limits/c.limits/climits.pass.cpp
index 317d5d5094f..d124f7ca28d 100644
--- a/libcxx/test/std/language.support/support.limits/c.limits/climits.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/c.limits/climits.pass.cpp
@@ -86,6 +86,8 @@
 #error ULLONG_MAX not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/denorm.style/check_values.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/denorm.style/check_values.pass.cpp
index 6b48dfbc379..adbd102dc20 100644
--- a/libcxx/test/std/language.support/support.limits/limits/denorm.style/check_values.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/denorm.style/check_values.pass.cpp
@@ -18,7 +18,7 @@ struct two {one _[2];};
 one test(std::float_round_style);
 two test(int);
 
-int main()
+int main(int, char**)
 {
     static_assert(std::round_indeterminate == -1,
                  "std::round_indeterminate == -1");
@@ -34,4 +34,6 @@ int main()
                  "sizeof(test(std::round_to_nearest)) == 1");
     static_assert(sizeof(test(1)) == 2,
                  "sizeof(test(1)) == 2");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/is_specialized.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/is_specialized.pass.cpp
index 4959d5f54b9..b836555afc7 100644
--- a/libcxx/test/std/language.support/support.limits/limits/is_specialized.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/is_specialized.pass.cpp
@@ -39,7 +39,7 @@ void test()
                  "std::numeric_limits<const volatile T>::is_specialized");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>();
     test<char>();
@@ -67,4 +67,6 @@ int main()
     test<long double>();
     static_assert(!std::numeric_limits<std::complex<double> >::is_specialized,
                  "!std::numeric_limits<std::complex<double> >::is_specialized");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/const_data_members.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/const_data_members.pass.cpp
index 012a9a8eef3..b5912130a8d 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/const_data_members.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/const_data_members.pass.cpp
@@ -68,7 +68,7 @@ void test(const T &) {}
 
 struct other {};
 
-int main()
+int main(int, char**)
 {
     // bool
     TEST_NUMERIC_LIMITS(bool)
@@ -205,4 +205,6 @@ int main()
     TEST_NUMERIC_LIMITS(const other)
     TEST_NUMERIC_LIMITS(volatile other)
     TEST_NUMERIC_LIMITS(const volatile other)
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/denorm_min.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/denorm_min.pass.cpp
index d67e8cbaba7..4f9f62873aa 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/denorm_min.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/denorm_min.pass.cpp
@@ -26,7 +26,7 @@ test(T expected)
     assert(std::numeric_limits<const volatile T>::denorm_min() == expected);
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(false);
     test<char>(0);
@@ -65,4 +65,6 @@ int main()
 #if !defined(__FLT_DENORM_MIN__) && !defined(FLT_TRUE_MIN)
 #error Test has no expected values for floating point types
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits.pass.cpp
index de9aa3395d6..139f4821dc8 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::digits == expected, "digits test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 1>();
     test<char, std::numeric_limits<char>::is_signed ? 7 : 8>();
@@ -54,4 +54,6 @@ int main()
     test<float, FLT_MANT_DIG>();
     test<double, DBL_MANT_DIG>();
     test<long double, LDBL_MANT_DIG>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits10.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits10.pass.cpp
index 9c2fcfb1797..efdfd70d79c 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits10.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits10.pass.cpp
@@ -29,7 +29,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_bounded, "digits10 test 8");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 0>();
     test<char, 2>();
@@ -58,4 +58,6 @@ int main()
     test<float, FLT_DIG>();
     test<double, DBL_DIG>();
     test<long double, LDBL_DIG>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/epsilon.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/epsilon.pass.cpp
index 691bd5b2765..60a905f79bb 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/epsilon.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/epsilon.pass.cpp
@@ -26,7 +26,7 @@ test(T expected)
     assert(std::numeric_limits<const volatile T>::epsilon() == expected);
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(false);
     test<char>(0);
@@ -55,4 +55,6 @@ int main()
     test<float>(FLT_EPSILON);
     test<double>(DBL_EPSILON);
     test<long double>(LDBL_EPSILON);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm.pass.cpp
index 05469f08c96..d5380c1a763 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::has_denorm == expected, "has_denorm test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, std::denorm_absent>();
     test<char, std::denorm_absent>();
@@ -53,4 +53,6 @@ int main()
     test<float, std::denorm_present>();
     test<double, std::denorm_present>();
     test<long double, std::denorm_present>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm_loss.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm_loss.pass.cpp
index 89bc78a48c2..77e5de6ab83 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm_loss.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_denorm_loss.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::has_denorm_loss == expected, "has_denorm_loss test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, false>();
@@ -53,4 +53,6 @@ int main()
     test<float, false>();
     test<double, false>();
     test<long double, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_infinity.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_infinity.pass.cpp
index abdd9b544ee..19d4fe29312 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_infinity.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_infinity.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::has_infinity == expected, "has_infinity test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, false>();
@@ -53,4 +53,6 @@ int main()
     test<float, true>();
     test<double, true>();
     test<long double, true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_quiet_NaN.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_quiet_NaN.pass.cpp
index a351bcef094..767df5ac27b 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_quiet_NaN.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_quiet_NaN.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::has_quiet_NaN == expected, "has_quiet_NaN test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, false>();
@@ -53,4 +53,6 @@ int main()
     test<float, true>();
     test<double, true>();
     test<long double, true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_signaling_NaN.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_signaling_NaN.pass.cpp
index bc74464e788..0908c49bc16 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_signaling_NaN.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/has_signaling_NaN.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::has_signaling_NaN == expected, "has_signaling_NaN test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, false>();
@@ -53,4 +53,6 @@ int main()
     test<float, true>();
     test<double, true>();
     test<long double, true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/infinity.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/infinity.pass.cpp
index 924f32a6b26..0004e4e6282 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/infinity.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/infinity.pass.cpp
@@ -28,7 +28,7 @@ test(T expected)
 
 extern float zero;
 
-int main()
+int main(int, char**)
 {
     test<bool>(false);
     test<char>(0);
@@ -57,6 +57,8 @@ int main()
     test<float>(1.f/zero);
     test<double>(1./zero);
     test<long double>(1./zero);
+
+  return 0;
 }
 
 float zero = 0;
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_bounded.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_bounded.pass.cpp
index 8f2cdb0a78f..d509be720e7 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_bounded.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_bounded.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_bounded == expected, "is_bounded test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, true>();
     test<char, true>();
@@ -53,4 +53,6 @@ int main()
     test<float, true>();
     test<double, true>();
     test<long double, true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_exact.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_exact.pass.cpp
index 2c769d87cf3..30dbd9ea11f 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_exact.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_exact.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_exact == expected, "is_exact test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, true>();
     test<char, true>();
@@ -53,4 +53,6 @@ int main()
     test<float, false>();
     test<double, false>();
     test<long double, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_iec559.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_iec559.pass.cpp
index c7edf178dc2..215407d74b3 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_iec559.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_iec559.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_iec559 == expected, "is_iec559 test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, false>();
@@ -57,4 +57,6 @@ int main()
 #else
     test<long double, true>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_integer.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_integer.pass.cpp
index 80a45fa29f8..66ce0cb2bad 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_integer.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_integer.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_integer == expected, "is_integer test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, true>();
     test<char, true>();
@@ -53,4 +53,6 @@ int main()
     test<float, false>();
     test<double, false>();
     test<long double, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_modulo.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_modulo.pass.cpp
index c364fd01bd1..2eb2c4ba494 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_modulo.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_modulo.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_modulo == expected, "is_modulo test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
 //    test<char, false>(); // don't know
@@ -53,4 +53,6 @@ int main()
     test<float, false>();
     test<double, false>();
     test<long double, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_signed.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_signed.pass.cpp
index 08dc5eb772f..818ad4db9f4 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_signed.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/is_signed.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::is_signed == expected, "is_signed test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, char(-1) < char(0)>();
@@ -53,4 +53,6 @@ int main()
     test<float, true>();
     test<double, true>();
     test<long double, true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/lowest.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/lowest.pass.cpp
index bb6ae168e72..adf147c7069 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/lowest.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/lowest.pass.cpp
@@ -32,7 +32,7 @@ test(T expected)
     assert(std::numeric_limits<const volatile T>::is_bounded);
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(false);
     test<char>(CHAR_MIN);
@@ -61,4 +61,6 @@ int main()
     test<float>(-FLT_MAX);
     test<double>(-DBL_MAX);
     test<long double>(-LDBL_MAX);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max.pass.cpp
index 0bf7237ad9e..91f353ab5e2 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max.pass.cpp
@@ -32,7 +32,7 @@ test(T expected)
     assert(std::numeric_limits<const volatile T>::is_bounded);
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(true);
     test<char>(CHAR_MAX);
@@ -61,4 +61,6 @@ int main()
     test<float>(FLT_MAX);
     test<double>(DBL_MAX);
     test<long double>(LDBL_MAX);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_digits10.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_digits10.pass.cpp
index 4b871487527..3cf7d509695 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_digits10.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_digits10.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::max_digits10 == expected, "max_digits10 test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 0>();
     test<char, 0>();
@@ -54,4 +54,6 @@ int main()
     test<float, 2+(FLT_MANT_DIG * 30103)/100000>();
     test<double, 2+(DBL_MANT_DIG * 30103)/100000>();
     test<long double, 2+(LDBL_MANT_DIG * 30103)/100000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent.pass.cpp
index 7ce1ac9d744..325ad797977 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::max_exponent == expected, "max_exponent test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 0>();
     test<char, 0>();
@@ -54,4 +54,6 @@ int main()
     test<float, FLT_MAX_EXP>();
     test<double, DBL_MAX_EXP>();
     test<long double, LDBL_MAX_EXP>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent10.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent10.pass.cpp
index e2bbdde1096..e1a4ffe29be 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent10.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/max_exponent10.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::max_exponent10 == expected, "max_exponent10 test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 0>();
     test<char, 0>();
@@ -54,4 +54,6 @@ int main()
     test<float, FLT_MAX_10_EXP>();
     test<double, DBL_MAX_10_EXP>();
     test<long double, LDBL_MAX_10_EXP>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min.pass.cpp
index 66ddaa474e9..0d2cb3c1bc3 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min.pass.cpp
@@ -32,7 +32,7 @@ test(T expected)
     assert(std::numeric_limits<const volatile T>::is_bounded || !std::numeric_limits<const volatile T>::is_signed);
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(false);
     test<char>(CHAR_MIN);
@@ -61,4 +61,6 @@ int main()
     test<float>(FLT_MIN);
     test<double>(DBL_MIN);
     test<long double>(LDBL_MIN);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent.pass.cpp
index 8fb4f09f6a7..5708d8a20f5 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::min_exponent == expected, "min_exponent test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 0>();
     test<char, 0>();
@@ -54,4 +54,6 @@ int main()
     test<float, FLT_MIN_EXP>();
     test<double, DBL_MIN_EXP>();
     test<long double, LDBL_MIN_EXP>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent10.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent10.pass.cpp
index 812dd53bbe0..f598d42fa8e 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent10.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/min_exponent10.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::min_exponent10 == expected, "min_exponent10 test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 0>();
     test<char, 0>();
@@ -54,4 +54,6 @@ int main()
     test<float, FLT_MIN_10_EXP>();
     test<double, DBL_MIN_10_EXP>();
     test<long double, LDBL_MIN_10_EXP>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/quiet_NaN.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/quiet_NaN.pass.cpp
index 852cf86a13a..f4ea61f23dc 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/quiet_NaN.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/quiet_NaN.pass.cpp
@@ -45,7 +45,7 @@ test()
     test_imp<T>(std::is_floating_point<T>());
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>();
     test<char>();
@@ -74,4 +74,6 @@ int main()
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/radix.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/radix.pass.cpp
index 8c9e48a2d71..8f13768b0bd 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/radix.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/radix.pass.cpp
@@ -25,7 +25,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::radix == expected, "radix test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, 2>();
     test<char, 2>();
@@ -54,4 +54,6 @@ int main()
     test<float, FLT_RADIX>();
     test<double, FLT_RADIX>();
     test<long double, FLT_RADIX>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_error.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_error.pass.cpp
index f2d962df4b6..ddc4490db0b 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_error.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_error.pass.cpp
@@ -26,7 +26,7 @@ test(T expected)
     assert(std::numeric_limits<const volatile T>::round_error() == expected);
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(false);
     test<char>(0);
@@ -55,4 +55,6 @@ int main()
     test<float>(0.5);
     test<double>(0.5);
     test<long double>(0.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_style.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_style.pass.cpp
index 43e962961a6..81d4ce6ebcf 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_style.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/round_style.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::round_style == expected, "round_style test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, std::round_toward_zero>();
     test<char, std::round_toward_zero>();
@@ -53,4 +53,6 @@ int main()
     test<float, std::round_to_nearest>();
     test<double, std::round_to_nearest>();
     test<long double, std::round_to_nearest>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/signaling_NaN.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/signaling_NaN.pass.cpp
index 312f6971498..70138671095 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/signaling_NaN.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/signaling_NaN.pass.cpp
@@ -45,7 +45,7 @@ test()
     test_imp<T>(std::is_floating_point<T>());
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>();
     test<char>();
@@ -74,4 +74,6 @@ int main()
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/tinyness_before.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/tinyness_before.pass.cpp
index 3e0ad694b44..c150e5f23d0 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/tinyness_before.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/tinyness_before.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::tinyness_before == expected, "tinyness_before test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, false>();
@@ -53,4 +53,6 @@ int main()
     test<float, false>();
     test<double, false>();
     test<long double, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/traps.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/traps.pass.cpp
index e71432b18a1..e7ea388192d 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/traps.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/traps.pass.cpp
@@ -31,7 +31,7 @@ test()
     static_assert(std::numeric_limits<const volatile T>::traps == expected, "traps test 4");
 }
 
-int main()
+int main(int, char**)
 {
     test<bool, false>();
     test<char, integral_types_trap>();
@@ -60,4 +60,6 @@ int main()
     test<float, false>();
     test<double, false>();
     test<long double, false>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.limits/default.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.limits/default.pass.cpp
index 3c7cefd55cf..6e258c13a78 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.limits/default.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.limits/default.pass.cpp
@@ -22,7 +22,7 @@ struct A
 
 bool operator == (const A& x, const A& y) {return x.data_ == y.data_;}
 
-int main()
+int main(int, char**)
 {
     static_assert(std::numeric_limits<A>::is_specialized == false,
                  "std::numeric_limits<A>::is_specialized == false");
@@ -79,4 +79,6 @@ int main()
                  "std::numeric_limits<A>::tinyness_before == false");
     static_assert(std::numeric_limits<A>::round_style == std::round_toward_zero,
                  "std::numeric_limits<A>::round_style == std::round_toward_zero");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/numeric.special/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/numeric.special/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.limits/limits/numeric.special/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/numeric.special/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/limits/round.style/check_values.pass.cpp b/libcxx/test/std/language.support/support.limits/limits/round.style/check_values.pass.cpp
index c6a01bf66fb..b1a4e4450a1 100644
--- a/libcxx/test/std/language.support/support.limits/limits/round.style/check_values.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/limits/round.style/check_values.pass.cpp
@@ -18,7 +18,7 @@ struct two {one _[2];};
 one test(std::float_denorm_style);
 two test(int);
 
-int main()
+int main(int, char**)
 {
     static_assert(std::denorm_indeterminate == -1,
                  "std::denorm_indeterminate == -1");
@@ -30,4 +30,6 @@ int main()
                  "sizeof(test(std::denorm_present)) == 1");
     static_assert(sizeof(test(1)) == 2,
                  "sizeof(test(1)) == 2");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/nothing_to_do.pass.cpp b/libcxx/test/std/language.support/support.limits/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/language.support/support.limits/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.pass.cpp
index 57234ad4362..5458e919429 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.pass.cpp
@@ -188,4 +188,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/any.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/any.version.pass.cpp
index 9bbaca7aa15..f5255c0e26a 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/any.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/any.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp
index 85bda432290..d590f98042d 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp
@@ -101,4 +101,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.pass.cpp
index 3fb2c7ed147..d8f6f548cd2 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.pass.cpp
@@ -118,4 +118,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/bit.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/bit.version.pass.cpp
index 6c26e06a0b0..3e42d06fbe8 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/bit.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/bit.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/charconv.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/charconv.pass.cpp
index 045dcb8ac38..2afe2e26ba5 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/charconv.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/charconv.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 //  ensure that the macros that are supposed to be defined in <utility> are defined.
 
@@ -28,4 +28,6 @@ int main()
 # error "__cpp_lib_fooby has an invalid value"
 #endif
 */
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/chrono.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/chrono.version.pass.cpp
index 9e434c5c253..88da2dcca6d 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/chrono.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/chrono.version.pass.cpp
@@ -78,4 +78,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/cmath.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/cmath.version.pass.cpp
index bcc2053585a..d81218e66ab 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/cmath.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/cmath.version.pass.cpp
@@ -87,4 +87,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/compare.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/compare.version.pass.cpp
index 2864c9f4eb0..7f1836fba00 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/compare.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/compare.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/complex.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/complex.version.pass.cpp
index c6a9b16481f..bcff0bbe185 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/complex.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/complex.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/concepts.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/concepts.version.pass.cpp
index 9d9b9bca3fe..16febf8d3e2 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/concepts.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/concepts.version.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 //  ensure that the macros that are supposed to be defined in <concepts> are defined.
 
@@ -30,4 +30,6 @@ int main()
 # error "__cpp_lib_fooby has an invalid value"
 #endif
 */
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/cstddef.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/cstddef.version.pass.cpp
index 82a0932d0dc..b18ea07ea0c 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/cstddef.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/cstddef.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/deque.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/deque.version.pass.cpp
index 53a1b33450b..9d07dcdd246 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/deque.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/deque.version.pass.cpp
@@ -95,4 +95,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/exception.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/exception.version.pass.cpp
index c27bdc6b063..1ecebb48f0f 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/exception.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/exception.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp
index 476a31ef93f..b05f41bb173 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 //  ensure that the macros that are supposed to be defined in <execution> are defined.
 
@@ -30,4 +30,6 @@ int main()
 # error "__cpp_lib_fooby has an invalid value"
 #endif
 */
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/filesystem.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/filesystem.version.pass.cpp
index 6638cdee90c..d1c09fc7ee4 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/filesystem.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/filesystem.version.pass.cpp
@@ -78,4 +78,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/forward_list.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/forward_list.version.pass.cpp
index 102cd29ea56..7ecad6d3e34 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/forward_list.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/forward_list.version.pass.cpp
@@ -144,4 +144,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/functional.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/functional.version.pass.cpp
index e1146423119..a29a1d708a3 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/functional.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/functional.version.pass.cpp
@@ -241,4 +241,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/iomanip.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/iomanip.version.pass.cpp
index bd2ea2417a2..23378e0e2e3 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/iomanip.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/iomanip.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/istream.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/istream.version.pass.cpp
index 9194ff85528..3d8fb7a4cf9 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/istream.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/istream.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/iterator.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/iterator.version.pass.cpp
index b1ad28206f7..9c1719b53cf 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/iterator.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/iterator.version.pass.cpp
@@ -179,4 +179,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/limits.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/limits.version.pass.cpp
index bb2005e327c..2d2f243e704 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/limits.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/limits.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/list.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/list.version.pass.cpp
index c1159cf73a1..b736d1f9a21 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/list.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/list.version.pass.cpp
@@ -144,4 +144,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/locale.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/locale.version.pass.cpp
index c5a5b543650..eeea5390afd 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/locale.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/locale.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/map.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/map.version.pass.cpp
index c1ecad72321..a41dd1b8e98 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/map.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/map.version.pass.cpp
@@ -167,4 +167,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.pass.cpp
index 55e595fa9a8..6c845d71feb 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.pass.cpp
@@ -243,4 +243,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/memory_resource.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/memory_resource.version.pass.cpp
index cb182adc16a..d712a8bca8d 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/memory_resource.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/memory_resource.version.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 //  ensure that the macros that are supposed to be defined in <memory_resource> are defined.
 
@@ -30,4 +30,6 @@ int main()
 # error "__cpp_lib_fooby has an invalid value"
 #endif
 */
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/mutex.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/mutex.version.pass.cpp
index 4986a1f192d..9dae806b812 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/mutex.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/mutex.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/new.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/new.version.pass.cpp
index 95a717dfbd2..5f012cd55f6 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/new.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/new.version.pass.cpp
@@ -101,4 +101,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/numeric.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/numeric.version.pass.cpp
index f44cbc2c75c..eb5eb557b7b 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/numeric.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/numeric.version.pass.cpp
@@ -87,4 +87,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/optional.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/optional.version.pass.cpp
index 59e698d769d..d88fbb0fee8 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/optional.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/optional.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.pass.cpp
index 17be75c2e72..d3ba25867d0 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.pass.cpp
@@ -55,4 +55,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/regex.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/regex.version.pass.cpp
index 412e29c6c54..66becadbbfb 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/regex.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/regex.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/scoped_allocator.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/scoped_allocator.version.pass.cpp
index d111f263c13..2ea98256e1b 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/scoped_allocator.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/scoped_allocator.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/set.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/set.version.pass.cpp
index c886850ceba..80cf9c0af3c 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/set.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/set.version.pass.cpp
@@ -144,4 +144,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/shared_mutex.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/shared_mutex.version.pass.cpp
index 12c58480bdf..7c92dfc085c 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/shared_mutex.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/shared_mutex.version.pass.cpp
@@ -110,4 +110,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/string.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/string.version.pass.cpp
index 0f1c37b90e4..bdd517da0de 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/string.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/string.version.pass.cpp
@@ -170,4 +170,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/string_view.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/string_view.version.pass.cpp
index adad6b084e3..816083e0d7f 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/string_view.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/string_view.version.pass.cpp
@@ -104,4 +104,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/tuple.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/tuple.version.pass.cpp
index e2d9865324e..5c1e6580c57 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/tuple.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/tuple.version.pass.cpp
@@ -153,4 +153,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.pass.cpp
index 59994b77956..7e8b3de35f4 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.pass.cpp
@@ -393,4 +393,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_map.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_map.version.pass.cpp
index f6f4e6cecc2..07eb1a9bc35 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_map.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_map.version.pass.cpp
@@ -167,4 +167,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_set.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_set.version.pass.cpp
index 07a3c302adc..845318a79a5 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_set.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/unordered_set.version.pass.cpp
@@ -144,4 +144,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/utility.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/utility.version.pass.cpp
index 6b051d289d4..1fd38627a71 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/utility.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/utility.version.pass.cpp
@@ -191,4 +191,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/variant.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/variant.version.pass.cpp
index 23a15a67060..7a17307460d 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/variant.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/variant.version.pass.cpp
@@ -52,4 +52,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/vector.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/vector.version.pass.cpp
index c22921e775d..3ea2a0cf00b 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/vector.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/vector.version.pass.cpp
@@ -118,4 +118,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
index aa409e1547a..b85d42d00ca 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
@@ -2174,4 +2174,4 @@
 
 #endif // TEST_STD_VER > 17
 
-int main() {}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/version.pass.cpp b/libcxx/test/std/language.support/support.limits/version.pass.cpp
index b67df2892f0..783af5c728b 100644
--- a/libcxx/test/std/language.support/support.limits/version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/version.pass.cpp
@@ -11,6 +11,8 @@
 
 #include <version>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.rtti/bad.cast/bad_cast.pass.cpp b/libcxx/test/std/language.support/support.rtti/bad.cast/bad_cast.pass.cpp
index 5f9dc962daf..23afd223cc4 100644
--- a/libcxx/test/std/language.support/support.rtti/bad.cast/bad_cast.pass.cpp
+++ b/libcxx/test/std/language.support/support.rtti/bad.cast/bad_cast.pass.cpp
@@ -12,7 +12,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_cast>::value),
                  "std::is_base_of<std::exception, std::bad_cast>::value");
@@ -23,4 +23,6 @@ int main()
     b2 = b;
     const char* w = b2.what();
     assert(w);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.rtti/bad.typeid/bad_typeid.pass.cpp b/libcxx/test/std/language.support/support.rtti/bad.typeid/bad_typeid.pass.cpp
index 90b6bc20a30..94424bb03ad 100644
--- a/libcxx/test/std/language.support/support.rtti/bad.typeid/bad_typeid.pass.cpp
+++ b/libcxx/test/std/language.support/support.rtti/bad.typeid/bad_typeid.pass.cpp
@@ -12,7 +12,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_typeid>::value),
                  "std::is_base_of<std::exception, std::bad_typeid>::value");
@@ -23,4 +23,6 @@ int main()
     b2 = b;
     const char* w = b2.what();
     assert(w);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.rtti/type.info/type_info.pass.cpp b/libcxx/test/std/language.support/support.rtti/type.info/type_info.pass.cpp
index fec07526a2e..980bfeeccdc 100644
--- a/libcxx/test/std/language.support/support.rtti/type.info/type_info.pass.cpp
+++ b/libcxx/test/std/language.support/support.rtti/type.info/type_info.pass.cpp
@@ -16,7 +16,7 @@
 bool test_constructor_explicit(std::type_info const&) { return false; }
 bool test_constructor_explicit(std::string const&) { return true; }
 
-int main()
+int main(int, char**)
 {
   {
     const std::type_info& t1 = typeid(int);
@@ -36,4 +36,6 @@ int main()
     // See: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=216201
     assert(test_constructor_explicit("abc"));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.rtti/type.info/type_info_hash.pass.cpp b/libcxx/test/std/language.support/support.rtti/type.info/type_info_hash.pass.cpp
index d519622b7b1..c65f3bbf790 100644
--- a/libcxx/test/std/language.support/support.rtti/type.info/type_info_hash.pass.cpp
+++ b/libcxx/test/std/language.support/support.rtti/type.info/type_info_hash.pass.cpp
@@ -12,11 +12,13 @@
 #include <cstring>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::type_info& t1 = typeid(int);
     const std::type_info& t2 = typeid(int);
     const std::type_info& t3 = typeid(short);
     assert(t1.hash_code() == t2.hash_code());
     assert(t1.hash_code() != t3.hash_code());
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.runtime/csetjmp.pass.cpp b/libcxx/test/std/language.support/support.runtime/csetjmp.pass.cpp
index dc68bf4a342..c1fa71b0e37 100644
--- a/libcxx/test/std/language.support/support.runtime/csetjmp.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/csetjmp.pass.cpp
@@ -15,10 +15,12 @@
 #error setjmp not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::jmp_buf jb;
     ((void)jb); // Prevent unused warning
     static_assert((std::is_same<decltype(std::longjmp(jb, 0)), void>::value),
                   "std::is_same<decltype(std::longjmp(jb, 0)), void>::value");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.runtime/csignal.pass.cpp b/libcxx/test/std/language.support/support.runtime/csignal.pass.cpp
index b827236bb7f..dcfb4f99f5f 100644
--- a/libcxx/test/std/language.support/support.runtime/csignal.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/csignal.pass.cpp
@@ -47,11 +47,13 @@
 #error SIGTERM not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::sig_atomic_t sig = 0;
     ((void)sig);
     typedef void (*func)(int);
     static_assert((std::is_same<decltype(std::signal(0, (func)0)), func>::value), "");
     static_assert((std::is_same<decltype(std::raise(0)), int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.runtime/cstdarg.pass.cpp b/libcxx/test/std/language.support/support.runtime/cstdarg.pass.cpp
index b3c919af05f..8d7fd70b75a 100644
--- a/libcxx/test/std/language.support/support.runtime/cstdarg.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/cstdarg.pass.cpp
@@ -30,8 +30,10 @@
 #error va_start not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::va_list va;
     ((void)va);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.runtime/cstdbool.pass.cpp b/libcxx/test/std/language.support/support.runtime/cstdbool.pass.cpp
index 98a0e7e4989..461e77c9983 100644
--- a/libcxx/test/std/language.support/support.runtime/cstdbool.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/cstdbool.pass.cpp
@@ -26,6 +26,8 @@
 #error false should not be defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp b/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
index bc2cfcbb49d..d8b6636795d 100644
--- a/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
@@ -49,7 +49,7 @@ void test_div_struct() {
     ((void) obj);
 };
 
-int main()
+int main(int, char**)
 {
     std::size_t s = 0;
     ((void)s);
@@ -108,4 +108,6 @@ int main()
     static_assert((std::is_same<decltype(std::wctomb(pc,L' ')), int>::value), "");
     static_assert((std::is_same<decltype(std::mbstowcs(pw,"",0)), std::size_t>::value), "");
     static_assert((std::is_same<decltype(std::wcstombs(pc,pwc,0)), std::size_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp b/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp
index 57fb0124515..a8c2dc7ff56 100644
--- a/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/ctime.pass.cpp
@@ -26,7 +26,7 @@
 #endif
 #endif
 
-int main()
+int main(int, char**)
 {
     std::clock_t c = 0;
     std::size_t s = 0;
@@ -58,4 +58,6 @@ int main()
     ((void)c1); // Prevent unused warning
     ((void)c2); // Prevent unused warning
     static_assert((std::is_same<decltype(std::strftime(c1,s,c2,&tm)), std::size_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.start.term/quick_exit.pass.cpp b/libcxx/test/std/language.support/support.start.term/quick_exit.pass.cpp
index 5b7c36b08af..50d408aa0ba 100644
--- a/libcxx/test/std/language.support/support.start.term/quick_exit.pass.cpp
+++ b/libcxx/test/std/language.support/support.start.term/quick_exit.pass.cpp
@@ -13,10 +13,12 @@
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
 #ifdef _LIBCPP_HAS_QUICK_EXIT
     std::at_quick_exit(f);
     std::quick_exit(0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.start.term/quick_exit_check1.fail.cpp b/libcxx/test/std/language.support/support.start.term/quick_exit_check1.fail.cpp
index c1703f2bee6..63c97f21025 100644
--- a/libcxx/test/std/language.support/support.start.term/quick_exit_check1.fail.cpp
+++ b/libcxx/test/std/language.support/support.start.term/quick_exit_check1.fail.cpp
@@ -15,11 +15,13 @@
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_QUICK_EXIT
     std::at_quick_exit(f);
 #else
 #error
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.start.term/quick_exit_check2.fail.cpp b/libcxx/test/std/language.support/support.start.term/quick_exit_check2.fail.cpp
index acf10068b97..28929b1aed3 100644
--- a/libcxx/test/std/language.support/support.start.term/quick_exit_check2.fail.cpp
+++ b/libcxx/test/std/language.support/support.start.term/quick_exit_check2.fail.cpp
@@ -14,11 +14,13 @@
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_QUICK_EXIT
     std::quick_exit(0);
 #else
 #error
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byte.pass.cpp b/libcxx/test/std/language.support/support.types/byte.pass.cpp
index a4a9e821908..842dc38d353 100644
--- a/libcxx/test/std/language.support/support.types/byte.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byte.pass.cpp
@@ -30,4 +30,6 @@ static_assert(!std::is_same<std::byte, unsigned char>::value, "" );
 // The standard doesn't outright say this, but it's pretty clear that it has to be true.
 static_assert(sizeof(std::byte) == 1, "" );
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/language.support/support.types/byteops/and.assign.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/and.assign.pass.cpp
index e4875d38f33..9ecdb5f6c0d 100644
--- a/libcxx/test/std/language.support/support.types/byteops/and.assign.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/and.assign.pass.cpp
@@ -20,7 +20,7 @@ constexpr std::byte test(std::byte b1, std::byte b2) {
     }
 
 
-int main () {
+int main(int, char**) {
     std::byte b;  // not constexpr, just used in noexcept check
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b8{static_cast<std::byte>(8)};
@@ -35,4 +35,6 @@ int main () {
     static_assert(std::to_integer<int>(test(b8, b1)) == 0, "");
     static_assert(std::to_integer<int>(test(b9, b1)) == 1, "");
     static_assert(std::to_integer<int>(test(b9, b8)) == 8, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/and.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/and.pass.cpp
index 312e679cd2c..d1dbc75f70c 100644
--- a/libcxx/test/std/language.support/support.types/byteops/and.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/and.pass.cpp
@@ -13,7 +13,7 @@
 
 // constexpr byte operator&(byte l, byte r) noexcept;
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b8{static_cast<std::byte>(8)};
     constexpr std::byte b9{static_cast<std::byte>(9)};
@@ -27,4 +27,6 @@ int main () {
     static_assert(std::to_integer<int>(b8 & b1) ==  0, "");
     static_assert(std::to_integer<int>(b9 & b1) ==  1, "");
     static_assert(std::to_integer<int>(b9 & b8) ==  8, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/enum_direct_init.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/enum_direct_init.pass.cpp
index 99660b6b180..5111667cee0 100644
--- a/libcxx/test/std/language.support/support.types/byteops/enum_direct_init.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/enum_direct_init.pass.cpp
@@ -14,7 +14,9 @@
 // XFAIL: clang-3.5, clang-3.6, clang-3.7, clang-3.8
 // XFAIL: apple-clang-6, apple-clang-7, apple-clang-8.0
 
-int main () {
+int main(int, char**) {
   constexpr std::byte b{42};
   static_assert(std::to_integer<int>(b) == 42, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/lshift.assign.fail.cpp b/libcxx/test/std/language.support/support.types/byteops/lshift.assign.fail.cpp
index 413b62b1f42..8f2134b2072 100644
--- a/libcxx/test/std/language.support/support.types/byteops/lshift.assign.fail.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/lshift.assign.fail.cpp
@@ -25,6 +25,8 @@ constexpr std::byte test(std::byte b) {
     }
 
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1 = test(std::byte{1});
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/lshift.assign.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/lshift.assign.pass.cpp
index 9fe86883f4e..3647f5c64fc 100644
--- a/libcxx/test/std/language.support/support.types/byteops/lshift.assign.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/lshift.assign.pass.cpp
@@ -22,7 +22,7 @@ constexpr std::byte test(std::byte b) {
     }
 
 
-int main () {
+int main(int, char**) {
     std::byte b;  // not constexpr, just used in noexcept check
     constexpr std::byte b2{static_cast<std::byte>(2)};
     constexpr std::byte b3{static_cast<std::byte>(3)};
@@ -32,4 +32,6 @@ int main () {
     static_assert(std::to_integer<int>(test(b2)) ==  8, "" );
     static_assert(std::to_integer<int>(test(b3)) == 12, "" );
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/lshift.fail.cpp b/libcxx/test/std/language.support/support.types/byteops/lshift.fail.cpp
index 6d889ed23e0..83ce5b81e3f 100644
--- a/libcxx/test/std/language.support/support.types/byteops/lshift.fail.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/lshift.fail.cpp
@@ -16,7 +16,9 @@
 // These functions shall not participate in overload resolution unless
 //   is_integral_v<IntegerType> is true.
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b2 = b1 << 2.0f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/lshift.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/lshift.pass.cpp
index 73cc66373c6..855eebdf4ae 100644
--- a/libcxx/test/std/language.support/support.types/byteops/lshift.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/lshift.pass.cpp
@@ -16,7 +16,7 @@
 // These functions shall not participate in overload resolution unless
 //   is_integral_v<IntegerType> is true.
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b3{static_cast<std::byte>(3)};
 
@@ -26,4 +26,6 @@ int main () {
     static_assert(std::to_integer<int>(b1 << 2) ==   4, "");
     static_assert(std::to_integer<int>(b3 << 4) ==  48, "");
     static_assert(std::to_integer<int>(b3 << 6) == 192, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/not.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/not.pass.cpp
index cb94e3659b6..d6252aa356e 100644
--- a/libcxx/test/std/language.support/support.types/byteops/not.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/not.pass.cpp
@@ -13,7 +13,7 @@
 
 // constexpr byte operator~(byte b) noexcept;
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b2{static_cast<std::byte>(2)};
     constexpr std::byte b8{static_cast<std::byte>(8)};
@@ -23,4 +23,6 @@ int main () {
     static_assert(std::to_integer<int>(~b1) == 254, "");
     static_assert(std::to_integer<int>(~b2) == 253, "");
     static_assert(std::to_integer<int>(~b8) == 247, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/or.assign.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/or.assign.pass.cpp
index cad3acef327..1216b852b82 100644
--- a/libcxx/test/std/language.support/support.types/byteops/or.assign.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/or.assign.pass.cpp
@@ -20,7 +20,7 @@ constexpr std::byte test(std::byte b1, std::byte b2) {
     }
 
 
-int main () {
+int main(int, char**) {
     std::byte b;  // not constexpr, just used in noexcept check
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b2{static_cast<std::byte>(2)};
@@ -36,4 +36,6 @@ int main () {
     static_assert(std::to_integer<int>(test(b8, b1)) ==  9, "");
     static_assert(std::to_integer<int>(test(b8, b2)) == 10, "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/or.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/or.pass.cpp
index 4b778398d93..69b5bfaacb2 100644
--- a/libcxx/test/std/language.support/support.types/byteops/or.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/or.pass.cpp
@@ -13,7 +13,7 @@
 
 // constexpr byte operator|(byte l, byte r) noexcept;
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b2{static_cast<std::byte>(2)};
     constexpr std::byte b8{static_cast<std::byte>(8)};
@@ -27,4 +27,6 @@ int main () {
     static_assert(std::to_integer<int>(b2 | b1) ==  3, "");
     static_assert(std::to_integer<int>(b8 | b1) ==  9, "");
     static_assert(std::to_integer<int>(b8 | b2) == 10, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/rshift.assign.fail.cpp b/libcxx/test/std/language.support/support.types/byteops/rshift.assign.fail.cpp
index dcd6567341e..714f5cd8b13 100644
--- a/libcxx/test/std/language.support/support.types/byteops/rshift.assign.fail.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/rshift.assign.fail.cpp
@@ -25,6 +25,8 @@ constexpr std::byte test(std::byte b) {
     }
 
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1 = test(std::byte{1});
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/rshift.assign.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/rshift.assign.pass.cpp
index bbb921240bb..b1ca9d85135 100644
--- a/libcxx/test/std/language.support/support.types/byteops/rshift.assign.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/rshift.assign.pass.cpp
@@ -22,7 +22,7 @@ constexpr std::byte test(std::byte b) {
     }
 
 
-int main () {
+int main(int, char**) {
     std::byte b;  // not constexpr, just used in noexcept check
     constexpr std::byte b16{static_cast<std::byte>(16)};
     constexpr std::byte b192{static_cast<std::byte>(192)};
@@ -31,4 +31,6 @@ int main () {
 
     static_assert(std::to_integer<int>(test(b16))  ==  4, "" );
     static_assert(std::to_integer<int>(test(b192)) == 48, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/rshift.fail.cpp b/libcxx/test/std/language.support/support.types/byteops/rshift.fail.cpp
index 1dc5f83cfca..6af06f4fc68 100644
--- a/libcxx/test/std/language.support/support.types/byteops/rshift.fail.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/rshift.fail.cpp
@@ -16,7 +16,9 @@
 // These functions shall not participate in overload resolution unless
 //   is_integral_v<IntegerType> is true.
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b2 = b1 >> 2.0f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/rshift.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/rshift.pass.cpp
index 2ca3c6c20b2..64db7556cd5 100644
--- a/libcxx/test/std/language.support/support.types/byteops/rshift.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/rshift.pass.cpp
@@ -22,7 +22,7 @@ constexpr std::byte test(std::byte b) {
     }
 
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b100{static_cast<std::byte>(100)};
     constexpr std::byte b115{static_cast<std::byte>(115)};
 
@@ -33,4 +33,6 @@ int main () {
     static_assert(std::to_integer<int>(b115 >> 3) ==  14, "");
     static_assert(std::to_integer<int>(b115 >> 6) ==   1, "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/to_integer.fail.cpp b/libcxx/test/std/language.support/support.types/byteops/to_integer.fail.cpp
index ea3836b16a4..64996358c9c 100644
--- a/libcxx/test/std/language.support/support.types/byteops/to_integer.fail.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/to_integer.fail.cpp
@@ -16,7 +16,9 @@
 // This function shall not participate in overload resolution unless
 //   is_integral_v<IntegerType> is true.
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     auto f = std::to_integer<float>(b1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/to_integer.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/to_integer.pass.cpp
index cdae92ac4c9..657d17d9c45 100644
--- a/libcxx/test/std/language.support/support.types/byteops/to_integer.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/to_integer.pass.cpp
@@ -16,7 +16,7 @@
 // This function shall not participate in overload resolution unless
 //   is_integral_v<IntegerType> is true.
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b3{static_cast<std::byte>(3)};
 
@@ -27,4 +27,6 @@ int main () {
 
     static_assert(std::to_integer<int>(b1) == 1, "");
     static_assert(std::to_integer<int>(b3) == 3, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/xor.assign.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/xor.assign.pass.cpp
index 8caeec7dcc5..c82a6fd191b 100644
--- a/libcxx/test/std/language.support/support.types/byteops/xor.assign.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/xor.assign.pass.cpp
@@ -20,7 +20,7 @@ constexpr std::byte test(std::byte b1, std::byte b2) {
     }
 
 
-int main () {
+int main(int, char**) {
     std::byte b;  // not constexpr, just used in noexcept check
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b8{static_cast<std::byte>(8)};
@@ -35,4 +35,6 @@ int main () {
     static_assert(std::to_integer<int>(test(b8, b1)) == 9, "");
     static_assert(std::to_integer<int>(test(b9, b1)) == 8, "");
     static_assert(std::to_integer<int>(test(b9, b8)) == 1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/byteops/xor.pass.cpp b/libcxx/test/std/language.support/support.types/byteops/xor.pass.cpp
index 1dbf07f36c0..150f455b1db 100644
--- a/libcxx/test/std/language.support/support.types/byteops/xor.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/byteops/xor.pass.cpp
@@ -13,7 +13,7 @@
 
 // constexpr byte operator^(byte l, byte r) noexcept;
 
-int main () {
+int main(int, char**) {
     constexpr std::byte b1{static_cast<std::byte>(1)};
     constexpr std::byte b8{static_cast<std::byte>(8)};
     constexpr std::byte b9{static_cast<std::byte>(9)};
@@ -27,4 +27,6 @@ int main () {
     static_assert(std::to_integer<int>(b8 ^ b1) == 9, "");
     static_assert(std::to_integer<int>(b9 ^ b1) == 8, "");
     static_assert(std::to_integer<int>(b9 ^ b8) == 1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/max_align_t.pass.cpp b/libcxx/test/std/language.support/support.types/max_align_t.pass.cpp
index 50c4f5ef5a6..a49f598dff7 100644
--- a/libcxx/test/std/language.support/support.types/max_align_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/max_align_t.pass.cpp
@@ -15,7 +15,7 @@
 #include <stdio.h>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 
 #if TEST_STD_VER > 17
@@ -40,4 +40,6 @@ int main()
                   std::alignment_of<void*>::value,
                   "std::alignment_of<std::max_align_t>::value >= "
                   "std::alignment_of<void*>::value");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/null.pass.cpp b/libcxx/test/std/language.support/support.types/null.pass.cpp
index ce8530a00d4..66ecdbc147c 100644
--- a/libcxx/test/std/language.support/support.types/null.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/null.pass.cpp
@@ -12,6 +12,8 @@
 #error NULL not defined
 #endif
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/nullptr_t.pass.cpp b/libcxx/test/std/language.support/support.types/nullptr_t.pass.cpp
index 01a674a0a22..14ab3c65d02 100644
--- a/libcxx/test/std/language.support/support.types/nullptr_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/nullptr_t.pass.cpp
@@ -74,7 +74,7 @@ void test_nullptr_conversions() {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     static_assert(sizeof(std::nullptr_t) == sizeof(void*),
                   "sizeof(std::nullptr_t) == sizeof(void*)");
@@ -103,4 +103,6 @@ int main()
         test_comparisons<void(*)()>();
     }
     test_nullptr_conversions();
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.fail.cpp b/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.fail.cpp
index e6dc3772b00..5802e46f1b8 100644
--- a/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.fail.cpp
+++ b/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.fail.cpp
@@ -10,7 +10,9 @@
 
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     std::ptrdiff_t i = static_cast<std::ptrdiff_t>(nullptr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.pass.cpp b/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.pass.cpp
index ab1f447cdc6..b7696df974b 100644
--- a/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/nullptr_t_integral_cast.pass.cpp
@@ -16,8 +16,10 @@
 #include <cstddef>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ptrdiff_t i = reinterpret_cast<std::ptrdiff_t>(nullptr);
     assert(i == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/offsetof.pass.cpp b/libcxx/test/std/language.support/support.types/offsetof.pass.cpp
index 4a9dfac5e54..756f55352ed 100644
--- a/libcxx/test/std/language.support/support.types/offsetof.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/offsetof.pass.cpp
@@ -21,7 +21,9 @@ struct A
     int x;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert(noexcept(offsetof(A, x)), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/ptrdiff_t.pass.cpp b/libcxx/test/std/language.support/support.types/ptrdiff_t.pass.cpp
index 9c6c36f383d..de6f7726fe2 100644
--- a/libcxx/test/std/language.support/support.types/ptrdiff_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/ptrdiff_t.pass.cpp
@@ -15,7 +15,7 @@
 //  2. be the same sizeof as void*.
 //  3. be a signed integral.
 
-int main()
+int main(int, char**)
 {
     static_assert(sizeof(std::ptrdiff_t) == sizeof(void*),
                   "sizeof(std::ptrdiff_t) == sizeof(void*)");
@@ -23,4 +23,6 @@ int main()
                   "std::is_signed<std::ptrdiff_t>::value");
     static_assert(std::is_integral<std::ptrdiff_t>::value,
                   "std::is_integral<std::ptrdiff_t>::value");
+
+  return 0;
 }
diff --git a/libcxx/test/std/language.support/support.types/size_t.pass.cpp b/libcxx/test/std/language.support/support.types/size_t.pass.cpp
index ba1f6467378..5c840457b37 100644
--- a/libcxx/test/std/language.support/support.types/size_t.pass.cpp
+++ b/libcxx/test/std/language.support/support.types/size_t.pass.cpp
@@ -15,7 +15,7 @@
 //  2. be the same sizeof as void*.
 //  3. be an unsigned integral.
 
-int main()
+int main(int, char**)
 {
     static_assert(sizeof(std::size_t) == sizeof(void*),
                   "sizeof(std::size_t) == sizeof(void*)");
@@ -23,4 +23,6 @@ int main()
                   "std::is_unsigned<std::size_t>::value");
     static_assert(std::is_integral<std::size_t>::value,
                   "std::is_integral<std::size_t>::value");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/c.locales/clocale.pass.cpp b/libcxx/test/std/localization/c.locales/clocale.pass.cpp
index 8217dd74da8..d8bd81b2ba3 100644
--- a/libcxx/test/std/localization/c.locales/clocale.pass.cpp
+++ b/libcxx/test/std/localization/c.locales/clocale.pass.cpp
@@ -43,7 +43,7 @@
 #error NULL not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::lconv lc;
     ((void)lc); // Prevent unused warning
@@ -51,4 +51,6 @@ int main()
     static_assert((std::is_same<decltype(std::setlocale(0, "")), char*>::value), "");
 #endif
     static_assert((std::is_same<decltype(std::localeconv()), std::lconv*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/compare.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/compare.pass.cpp
index 33a94f9900d..1d76fa6094f 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/compare.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/compare.pass.cpp
@@ -32,7 +32,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -68,4 +68,6 @@ int main()
                              s3.data(), s3.data() + s3.size()) == 1);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/hash.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/hash.pass.cpp
index 21cf03681ee..40c15d6e9f4 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/hash.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/hash.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     std::locale l(LOCALE_en_US_UTF_8);
     {
@@ -39,4 +39,6 @@ int main()
         assert(f.hash(x1.data(), x1.data() + x1.size())
             != f.hash(x2.data(), x2.data() + x2.size()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/transform.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/transform.pass.cpp
index 7cd3d0fe5e2..0b86979f55d 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/transform.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/transform.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -53,4 +53,6 @@ int main()
             assert(f.transform(x.data(), x.data() + x.size()) == x);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/types.pass.cpp
index f00c8fd959d..f4dfd652227 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate.byname/types.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     std::locale l(LOCALE_en_US_UTF_8);
     {
@@ -43,4 +43,6 @@ int main()
         assert(&std::use_facet<std::collate<wchar_t> >(l)
             == &std::use_facet<std::collate_byname<wchar_t> >(l));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/ctor.pass.cpp
index ded9ebae3ad..856074d391b 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 template <class C> int my_facet<C>::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet<char>);
@@ -63,4 +63,6 @@ int main()
         assert(my_facet<wchar_t>::count == 1);
     }
     assert(my_facet<wchar_t>::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/compare.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/compare.pass.cpp
index ff5aa4bddc4..bfbbebe3985 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/compare.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/compare.pass.cpp
@@ -16,7 +16,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -45,4 +45,6 @@ int main()
         assert(f.compare(ib+1, ib+3, ia, ia+sa) == 1);
         assert(f.compare(ia, ia+3, ib, ib+3) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/hash.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/hash.pass.cpp
index 61d5a640f36..07e29b17f61 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/hash.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/hash.pass.cpp
@@ -18,7 +18,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -35,4 +35,6 @@ int main()
         assert(f.hash(x1.data(), x1.data() + x1.size())
             != f.hash(x2.data(), x2.data() + x2.size()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/transform.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/transform.pass.cpp
index 7b8c9915f28..7588a82be41 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/transform.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.members/transform.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         const std::collate<wchar_t>& f = std::use_facet<std::collate<wchar_t> >(l);
         assert(f.transform(x.data(), x.data() + x.size()) == x);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/locale.collate.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp
index 45957c3be28..63e2739f4e6 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -47,4 +47,6 @@ int main()
         static_assert((std::is_same<std::collate<wchar_t>::string_type, std::wstring>::value), "");
         static_assert((std::is_base_of<std::locale::facet, std::collate<wchar_t> >::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.collate/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/category.collate/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.collate/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.collate/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/ctype_base.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/ctype_base.pass.cpp
index 92024149c08..b7da91b4686 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/ctype_base.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/ctype_base.pass.cpp
@@ -38,7 +38,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     assert(std::ctype_base::space);
     assert(std::ctype_base::print);
@@ -74,4 +74,6 @@ int main()
     test(std::ctype_base::blank);
     test(std::ctype_base::alnum);
     test(std::ctype_base::graph);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.dtor/dtor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.dtor/dtor.pass.cpp
index 5ba7a67e40c..e38af450f7f 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.dtor/dtor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.dtor/dtor.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "count_new.hpp"
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new std::ctype<char>);
@@ -36,4 +36,6 @@ int main()
         assert(globalMemCounter.checkDeleteArrayCalledEq(0));
     }
     assert(globalMemCounter.checkDeleteArrayCalledEq(1));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/ctor.pass.cpp
index 20eef3354c5..4ec37db021a 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/ctor.pass.cpp
@@ -29,7 +29,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -46,4 +46,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_1.pass.cpp
index c4561f7964f..562f6c25e6b 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -55,4 +55,6 @@ int main()
         assert(f.is(F::graph, '.'));
         assert(!f.is(F::graph,  '\x07'));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_many.pass.cpp
index 9415d8b5a7d..c073a955e78 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/is_many.pass.cpp
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -114,4 +114,6 @@ int main()
         assert( (m[5] & F::alnum));
         assert( (m[5] & F::graph));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_1.pass.cpp
index b0fa41a2f3d..d2fa02201a3 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.narrow('a', '*') == 'a');
         assert(f.narrow('1', '*') == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_many.pass.cpp
index 01bb8053456..48146954035 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/narrow_many.pass.cpp
@@ -17,7 +17,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -34,4 +34,6 @@ int main()
         assert(v[4] == 'a');
         assert(v[5] == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_is.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_is.pass.cpp
index 3f4f0490205..043ca679608 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_is.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_is.pass.cpp
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -40,4 +40,6 @@ int main()
         assert(f.scan_is(F::alnum, in.data(), in.data() + in.size()) - in.data() == 1);
         assert(f.scan_is(F::graph, in.data(), in.data() + in.size()) - in.data() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_not.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_not.pass.cpp
index 6cd24a82e07..066a06a7f4c 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_not.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/scan_not.pass.cpp
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -40,4 +40,6 @@ int main()
         assert(f.scan_not(F::alnum, in.data(), in.data() + in.size()) - in.data() == 0);
         assert(f.scan_not(F::graph, in.data(), in.data() + in.size()) - in.data() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/table.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/table.pass.cpp
index 9d815196b18..6a0fea0b1fd 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/table.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/table.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::ctype<char> F;
     {
@@ -29,4 +29,6 @@ int main()
         const F& f = std::use_facet<F>(l);
         assert(f.table() == table);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_1.pass.cpp
index 2b817002ce7..ddf4fbdb057 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.tolower('a') == 'a');
         assert(f.tolower('1') == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_many.pass.cpp
index 036ed25c6a3..b307d462735 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/tolower_many.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -32,4 +32,6 @@ int main()
         assert(in[4] == 'a');
         assert(in[5] == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_1.pass.cpp
index c393bb91b8e..8b5505910ee 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.toupper('a') == 'A');
         assert(f.toupper('1') == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_many.pass.cpp
index 25af985f7c8..3d1c453cf39 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/toupper_many.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -32,4 +32,6 @@ int main()
         assert(in[4] == 'A');
         assert(in[5] == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_1.pass.cpp
index 5b9f74bad91..81c3ab6b3c4 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.widen('a') == 'a');
         assert(f.widen('1') == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_many.pass.cpp
index ab3a838c087..35d9335c252 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.members/widen_many.pass.cpp
@@ -17,7 +17,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -34,4 +34,6 @@ int main()
         assert(v[4] == 'a');
         assert(v[5] == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.statics/classic_table.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.statics/classic_table.pass.cpp
index 1aef57d3fb7..7f46238d682 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.statics/classic_table.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.statics/classic_table.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::ctype<char> F;
     assert(F::classic_table() != 0);
@@ -55,4 +55,6 @@ int main()
         assert(((p[i] & ~set) & defined) == 0);   // no extra ones
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/facet.ctype.char.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp
index b23f9ef83d8..c46dbb3e6f1 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -35,4 +35,6 @@ int main()
         static_assert((std::is_base_of<std::ctype_base, std::ctype<char> >::value), "");
         static_assert((std::is_base_of<std::locale::facet, std::ctype<char> >::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp
index d5cde475453..03d17375e5e 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp
@@ -36,7 +36,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet(LOCALE_en_US));
@@ -68,4 +68,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char16_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char16_t.pass.cpp
index 4d2803815de..eedf192db26 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char16_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char16_t.pass.cpp
@@ -34,7 +34,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet("en_US"));
@@ -66,4 +66,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char32_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char32_t.pass.cpp
index 50bf5834902..8e5d70356ab 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char32_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char32_t.pass.cpp
@@ -34,7 +34,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet("en_US"));
@@ -66,4 +66,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_wchar_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_wchar_t.pass.cpp
index 2379b163151..5503192ca98 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_wchar_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_wchar_t.pass.cpp
@@ -38,7 +38,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet(LOCALE_en_US_UTF_8));
@@ -70,4 +70,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/codecvt_base.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/codecvt_base.pass.cpp
index f6b94c5f185..c2e40542e0e 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/codecvt_base.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/codecvt_base.pass.cpp
@@ -17,10 +17,12 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::codecvt_base::ok == 0);
     assert(std::codecvt_base::partial == 1);
     assert(std::codecvt_base::error == 2);
     assert(std::codecvt_base::noconv == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char.pass.cpp
index e12d301686c..3f0dc9e7cc1 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char16_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char16_t.pass.cpp
index e0ed00dfd61..e2df342d4e6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char16_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char16_t.pass.cpp
@@ -35,7 +35,7 @@ int my_facet::count = 0;
 
 //#endif
 
-int main()
+int main(int, char**)
 {
 //#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     {
@@ -54,4 +54,6 @@ int main()
     }
     assert(my_facet::count == 0);
 //#endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char32_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char32_t.pass.cpp
index 56d63764df6..0df7f3515df 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char32_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_char32_t.pass.cpp
@@ -35,7 +35,7 @@ int my_facet::count = 0;
 
 //#endif
 
-int main()
+int main(int, char**)
 {
 //#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     {
@@ -54,4 +54,6 @@ int main()
     }
     assert(my_facet::count == 0);
 //#endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_wchar_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_wchar_t.pass.cpp
index 8f4293ee83b..6917e1b7220 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_wchar_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/ctor_wchar_t.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_always_noconv.pass.cpp
index 2f84eb6c92b..e1741aec05e 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_always_noconv.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(!f.always_noconv());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_encoding.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_encoding.pass.cpp
index 4a30c4ee8f9..f4614984ad7 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_encoding.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.encoding() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_in.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_in.pass.cpp
index 6a883d3d44f..2a6a07ef957 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_in.pass.cpp
@@ -21,7 +21,7 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const char from[] = "some text";
@@ -36,4 +36,6 @@ int main()
     assert(to_next - to == 9);
     for (unsigned i = 0; i < 9; ++i)
         assert(to[i] == from[i]);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_length.pass.cpp
index a48b902e1dd..038ae971136 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_length.pass.cpp
@@ -17,7 +17,7 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -28,4 +28,6 @@ int main()
     assert(f.length(mbs, from, from+10, 9) == 9);
     assert(f.length(mbs, from, from+10, 10) == 10);
     assert(f.length(mbs, from, from+10, 100) == 10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_max_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_max_length.pass.cpp
index 69c711f60a3..bcaa7052876 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_max_length.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.max_length() == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_out.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_out.pass.cpp
index 9b5d0f988ab..cff42b0c054 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_out.pass.cpp
@@ -23,7 +23,7 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -41,4 +41,6 @@ int main()
         for (unsigned i = 0; i < 9; ++i)
             assert(to[i] == from[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_unshift.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_unshift.pass.cpp
index bde44c0889a..5b027bae7b5 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char16_t_unshift.pass.cpp
@@ -20,7 +20,7 @@
 
 typedef std::codecvt<char16_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     std::vector<char> to(3);
@@ -29,4 +29,6 @@ int main()
     char* to_next = 0;
     assert(f.unshift(mbs, to.data(), to.data() + to.size(), to_next) == F::noconv);
     assert(to_next == to.data());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_always_noconv.pass.cpp
index 2ef1e5c657d..2b2f136e3b4 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_always_noconv.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(!f.always_noconv());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_encoding.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_encoding.pass.cpp
index 834bd607689..0d2f35fc2c2 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_encoding.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.encoding() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_in.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_in.pass.cpp
index 8472a569226..eb7c53fcea6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_in.pass.cpp
@@ -21,7 +21,7 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const char from[] = "some text";
@@ -36,4 +36,6 @@ int main()
     assert(to_next - to == 9);
     for (unsigned i = 0; i < 9; ++i)
         assert(to[i] == static_cast<char32_t>(from[i]));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_length.pass.cpp
index 6986314e3f4..da853068883 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_length.pass.cpp
@@ -17,7 +17,7 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -28,4 +28,6 @@ int main()
     assert(f.length(mbs, from, from+10, 9) == 9);
     assert(f.length(mbs, from, from+10, 10) == 10);
     assert(f.length(mbs, from, from+10, 100) == 10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_max_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_max_length.pass.cpp
index 921ec18549c..f31dba747c7 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_max_length.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.max_length() == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_out.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_out.pass.cpp
index 210f8c052e5..7ed5609436c 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_out.pass.cpp
@@ -23,7 +23,7 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -41,4 +41,6 @@ int main()
         for (unsigned i = 0; i < 9; ++i)
             assert(static_cast<char32_t>(to[i]) == from[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_unshift.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_unshift.pass.cpp
index 26981d3c85c..aaf9a6a20e6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char32_t_unshift.pass.cpp
@@ -20,7 +20,7 @@
 
 typedef std::codecvt<char32_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     std::vector<char> to(3);
@@ -29,4 +29,6 @@ int main()
     char* to_next = 0;
     assert(f.unshift(mbs, to.data(), to.data() + to.size(), to_next) == F::noconv);
     assert(to_next == to.data());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_always_noconv.pass.cpp
index 2590c2b0e62..c253bbed72f 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_always_noconv.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.always_noconv());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_encoding.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_encoding.pass.cpp
index 571ab84d888..79c26add6ab 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_encoding.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.encoding() == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_in.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_in.pass.cpp
index 2b7c610e461..1f2cdb6be45 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_in.pass.cpp
@@ -21,7 +21,7 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const std::basic_string<F::intern_type> from("some text");
@@ -34,4 +34,6 @@ int main()
                      to.data(), to.data() + to.size(), to_next) == F::noconv);
     assert(from_next == from.data());
     assert(to_next == to.data());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_length.pass.cpp
index b930009b516..ad45cba5f43 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_length.pass.cpp
@@ -17,7 +17,7 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -28,4 +28,6 @@ int main()
     assert(f.length(mbs, from, from+10, 10) == 10);
     assert(f.length(mbs, from, from+10, 11) == 10);
     assert(f.length(mbs, from, from+10, 100) == 10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_max_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_max_length.pass.cpp
index adc0b1707b1..437e72b94ca 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_max_length.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.max_length() == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_out.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_out.pass.cpp
index 28b4be7455b..be266746cda 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_out.pass.cpp
@@ -21,7 +21,7 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const std::basic_string<F::intern_type> from("some text");
@@ -34,4 +34,6 @@ int main()
                       to.data(), to.data() + to.size(), to_next) == F::noconv);
     assert(from_next == from.data());
     assert(to_next == to.data());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_unshift.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_unshift.pass.cpp
index 56c10aa52e4..a3d9e3d14bd 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/char_unshift.pass.cpp
@@ -20,7 +20,7 @@
 
 typedef std::codecvt<char, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     std::vector<char> to(3);
@@ -29,4 +29,6 @@ int main()
     char* to_next = 0;
     assert(f.unshift(mbs, to.data(), to.data() + to.size(), to_next) == F::noconv);
     assert(to_next == to.data());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/utf_sanity_check.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/utf_sanity_check.pass.cpp
index 2d338dd8ee0..eaae7b6e97b 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/utf_sanity_check.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/utf_sanity_check.pass.cpp
@@ -20,7 +20,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt<char32_t, char, std::mbstate_t> F32_8;
     typedef std::codecvt<char16_t, char, std::mbstate_t> F16_8;
@@ -123,4 +123,6 @@ int main()
             assert(c32 == c32x);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_always_noconv.pass.cpp
index df645174767..484b2213d24 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_always_noconv.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(!f.always_noconv());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_encoding.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_encoding.pass.cpp
index ed33018b274..9c075af1372 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_encoding.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.encoding() == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_in.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_in.pass.cpp
index 7ca632e4e5e..bec0e6cb0ac 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_in.pass.cpp
@@ -22,7 +22,7 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const std::basic_string<F::extern_type> from("some text");
@@ -39,4 +39,6 @@ int main()
     assert(static_cast<std::size_t>(to_next - to.data()) == expected.size());
     assert(static_cast<std::size_t>(to_next - to.data()) == expected.size());
     assert(to == expected);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_length.pass.cpp
index 0fcab1af7ae..4fd5d329386 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_length.pass.cpp
@@ -17,7 +17,7 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -28,4 +28,6 @@ int main()
     assert(f.length(mbs, from, from+10, 10) == 10);
     assert(f.length(mbs, from, from+10, 11) == 10);
     assert(f.length(mbs, from, from+10, 100) == 10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_max_length.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_max_length.pass.cpp
index fefd11016fe..90d91315197 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_max_length.pass.cpp
@@ -17,9 +17,11 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
     assert(f.max_length() == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_out.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_out.pass.cpp
index 8769b881469..bc12bdbce64 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_out.pass.cpp
@@ -23,7 +23,7 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     const F& f = std::use_facet<F>(l);
@@ -67,4 +67,6 @@ int main()
         assert(static_cast<std::size_t>(to_next - to.data()) == to.size()-1);
         assert(to.data() == std::string("some te"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_unshift.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_unshift.pass.cpp
index 9241c7a4702..e0f7c3c9520 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.members/wchar_t_unshift.pass.cpp
@@ -22,7 +22,7 @@
 
 typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     std::vector<F::extern_type> to(3);
@@ -31,4 +31,6 @@ int main()
     F::extern_type* to_next = 0;
     assert(f.unshift(mbs, to.data(), to.data() + to.size(), to_next) == F::ok);
     assert(to_next == to.data());
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/locale.codecvt.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp
index 12fee2682da..455cf03ee71 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp
@@ -24,7 +24,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt<char, char, std::mbstate_t> F;
     static_assert((std::is_base_of<std::locale::facet, F>::value), "");
@@ -37,4 +37,6 @@ int main()
     const F& f = std::use_facet<F>(l);
     ((void)f); // Prevent unused warning
     (void)F::id;
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char16_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char16_t.pass.cpp
index b01bd5a7abd..f52c60f1bfd 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char16_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char16_t.pass.cpp
@@ -24,7 +24,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt<char16_t, char, std::mbstate_t> F;
     static_assert((std::is_base_of<std::locale::facet, F>::value), "");
@@ -37,4 +37,6 @@ int main()
     const F& f = std::use_facet<F>(l);
     (void)F::id;
     ((void)f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char32_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char32_t.pass.cpp
index 6ad4697542d..c75de419c86 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char32_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char32_t.pass.cpp
@@ -24,7 +24,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt<char32_t, char, std::mbstate_t> F;
     static_assert((std::is_base_of<std::locale::facet, F>::value), "");
@@ -37,4 +37,6 @@ int main()
     const F& f = std::use_facet<F>(l);
     (void)F::id;
     ((void)f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp
index 6c19e41a8e4..07e25be718c 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp
@@ -24,7 +24,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt<wchar_t, char, std::mbstate_t> F;
     static_assert((std::is_base_of<std::locale::facet, F>::value), "");
@@ -37,4 +37,6 @@ int main()
     const F& f = std::use_facet<F>(l);
     ((void)f); // Prevent unused warning
     (void)F::id;
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_1.pass.cpp
index 32acd85d18b..3331c5a67d8 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_1.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -108,4 +108,6 @@ int main()
             assert(!f.is(F::upper, L'\x00DA'));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_many.pass.cpp
index 1087b88c0c2..6751fd60de0 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/is_many.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -243,4 +243,6 @@ int main()
             assert( (m[6] & F::graph));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/mask.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/mask.pass.cpp
index 45d90ddd540..3a6360eb9de 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/mask.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/mask.pass.cpp
@@ -16,7 +16,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l("C");
@@ -49,4 +49,6 @@ int main()
             assert( cf.is(CF::alpha,  'a'));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_1.pass.cpp
index 19d751d2995..6d193772501 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_1.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::string(LOCALE_fr_CA_ISO8859_1));
@@ -52,4 +52,6 @@ int main()
             assert(f.narrow(L'\xDA', '*') == '*');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_many.pass.cpp
index c51b97311a1..7ab4874fbcd 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/narrow_many.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_fr_CA_ISO8859_1);
@@ -60,4 +60,6 @@ int main()
             assert(v[6] == '*');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_is.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_is.pass.cpp
index 6c875863fb5..b736dd7862c 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_is.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_is.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -67,4 +67,6 @@ int main()
             assert(f.scan_is(F::graph, in.data(), in.data() + in.size()) - in.data() == 2);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_not.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_not.pass.cpp
index dbeeae4c699..fa7674a8ca0 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_not.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/scan_not.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -67,4 +67,6 @@ int main()
             assert(f.scan_not(F::graph, in.data(), in.data() + in.size()) - in.data() == 0);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_1.pass.cpp
index 3f9ab9dce27..ab5daa7aa38 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_1.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l;
@@ -88,4 +88,6 @@ int main()
             assert(f.tolower(L'\xFA') == L'\xFA');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_many.pass.cpp
index 29021e0f4ce..29403cb1010 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/tolower_many.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l;
@@ -94,4 +94,6 @@ int main()
             assert(in[6] == L'1');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_1.pass.cpp
index b9c882c9a74..56304a7558a 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_1.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l;
@@ -90,4 +90,6 @@ int main()
             assert(f.toupper(L'\xFA') == L'\xFA');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_many.pass.cpp
index 2b0669cb30e..bfc3bf848ad 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/toupper_many.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l;
@@ -94,4 +94,6 @@ int main()
             assert(in[6] == L'1');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/types.pass.cpp
index 9ec94681611..ce0a0e30ed6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/types.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -56,4 +56,6 @@ int main()
                 == &std::use_facet<std::ctype_byname<wchar_t> >(l));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_1.pass.cpp
index 5752bb82bb8..1dc9b7de805 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_1.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l;
@@ -61,4 +61,6 @@ int main()
 #endif
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_many.pass.cpp
index 4f5efca1d66..67a97ba6826 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype.byname/widen_many.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(LOCALE_en_US_UTF_8);
@@ -67,4 +67,6 @@ int main()
 #endif
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/ctor.pass.cpp
index e41b93b78a2..f53d4e9645d 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/ctor.pass.cpp
@@ -30,7 +30,7 @@ public:
 
 template <class C> int my_facet<C>::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet<wchar_t>);
@@ -47,4 +47,6 @@ int main()
         assert(my_facet<wchar_t>::count == 1);
     }
     assert(my_facet<wchar_t>::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_1.pass.cpp
index a48f75f4f7d..23a1aa9d21a 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -55,4 +55,6 @@ int main()
         assert(f.is(F::graph, L'.'));
         assert(!f.is(F::graph,  L'\x07'));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_many.pass.cpp
index f348d208077..d9dd5b58ab4 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/is_many.pass.cpp
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -114,4 +114,6 @@ int main()
         assert( (m[5] & F::alnum));
         assert( (m[5] & F::graph));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_1.pass.cpp
index 1e1194bdad8..55e1f378b43 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.narrow(L'a', '*') == 'a');
         assert(f.narrow(L'1', '*') == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_many.pass.cpp
index 523fb250342..47c2b51887e 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/narrow_many.pass.cpp
@@ -17,7 +17,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -34,4 +34,6 @@ int main()
         assert(v[4] == 'a');
         assert(v[5] == '1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_is.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_is.pass.cpp
index 23718fec18a..1891b155b31 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_is.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_is.pass.cpp
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -40,4 +40,6 @@ int main()
         assert(f.scan_is(F::alnum, in.data(), in.data() + in.size()) - in.data() == 1);
         assert(f.scan_is(F::graph, in.data(), in.data() + in.size()) - in.data() == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_not.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_not.pass.cpp
index 22bc1470199..40cc8c0fa0d 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_not.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/scan_not.pass.cpp
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -40,4 +40,6 @@ int main()
         assert(f.scan_not(F::alnum, in.data(), in.data() + in.size()) - in.data() == 0);
         assert(f.scan_not(F::graph, in.data(), in.data() + in.size()) - in.data() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_1.pass.cpp
index b5c402de212..1ae14410c6f 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.tolower(L'a') == L'a');
         assert(f.tolower(L'1') == L'1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_many.pass.cpp
index 92bbc8ceb43..711343d3c5a 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/tolower_many.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -32,4 +32,6 @@ int main()
         assert(in[4] == L'a');
         assert(in[5] == L'1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_1.pass.cpp
index 0ed6e4504fb..fbc28a1b87c 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.toupper(L'a') == L'A');
         assert(f.toupper(L'1') == L'1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_many.pass.cpp
index 0510778eb3b..963e894a7e1 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/toupper_many.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -32,4 +32,6 @@ int main()
         assert(in[4] == L'A');
         assert(in[5] == L'1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_1.pass.cpp
index 1737de8f0f7..c2570a31136 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_1.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -29,4 +29,6 @@ int main()
         assert(f.widen('a') == L'a');
         assert(f.widen('1') == L'1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_many.pass.cpp
index 3942268ebd2..a43817a25a1 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.members/widen_many.pass.cpp
@@ -17,7 +17,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -34,4 +34,6 @@ int main()
         assert(v[4] == L'a');
         assert(v[5] == L'1');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/locale.ctype.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp
index 89ac905a2e5..35b5d3282b9 100644
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -35,4 +35,6 @@ int main()
         static_assert((std::is_base_of<std::ctype_base, std::ctype<wchar_t> >::value), "");
         static_assert((std::is_base_of<std::locale::facet, std::ctype<wchar_t> >::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages.byname/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages.byname/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages.byname/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages.byname/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/ctor.pass.cpp
index df42b522c7b..ddbbe66694b 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.members/not_testable.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.members/not_testable.pass.cpp
index 994a97211a4..c0166f80f34 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.members/not_testable.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.members/not_testable.pass.cpp
@@ -28,6 +28,8 @@ public:
         : std::messages<CharT>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/locale.messages.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/messages_base.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/messages_base.pass.cpp
index 7f2e4f9b9ab..ce6d70be728 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/messages_base.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/messages_base.pass.cpp
@@ -17,7 +17,9 @@
 #include <locale>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::messages_base mb;
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/types.pass.cpp
index 454d9b18242..436290698cc 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/locale.messages/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <locale>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::messages<char> >::value), "");
     static_assert((std::is_base_of<std::messages_base, std::messages<char> >::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::messages<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::messages<char>::string_type, std::string>::value), "");
     static_assert((std::is_same<std::messages<wchar_t>::string_type, std::wstring>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.messages/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/category.messages/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.messages/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.messages/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/ctor.pass.cpp
index f70f8eeadd3..360ff3ad61f 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp
index 94f9bd7a9a6..9fec21f51b9 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_en_US.pass.cpp
@@ -43,7 +43,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_en_US_UTF_8);
@@ -719,4 +719,6 @@ int main()
             assert(err == std::ios_base::failbit);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp
index 27ae11eed57..292f5eaea92 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp
@@ -76,7 +76,7 @@ static std::wstring convert_thousands_sep(std::wstring const& in) {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_fr_FR_UTF_8);
@@ -753,4 +753,6 @@ int main()
             assert(ex == 123456789);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_ru_RU.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_ru_RU.pass.cpp
index b543799accb..c13849804fc 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_ru_RU.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_ru_RU.pass.cpp
@@ -55,7 +55,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_ru_RU_UTF_8);
@@ -735,4 +735,6 @@ int main()
             assert(ex == -123456789);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_zh_CN.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_zh_CN.pass.cpp
index 20ba6f4914a..9b006f55b7a 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_zh_CN.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_zh_CN.pass.cpp
@@ -49,7 +49,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_zh_CN_UTF_8);
@@ -725,4 +725,6 @@ int main()
             assert(err == std::ios_base::failbit);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp
index a5cb05334c4..1b1a471e185 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_string_en_US.pass.cpp
@@ -43,7 +43,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_en_US_UTF_8);
@@ -727,4 +727,6 @@ int main()
             assert(ex == L"");
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/types.pass.cpp
index 9ad7528c205..7bc04801efa 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <locale>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::money_get<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::money_get<wchar_t> >::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::money_get<wchar_t>::iter_type, std::istreambuf_iterator<wchar_t> >::value), "");
     static_assert((std::is_same<std::money_get<char>::string_type, std::string>::value), "");
     static_assert((std::is_same<std::money_get<wchar_t>::string_type, std::wstring>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/ctor.pass.cpp
index bdbb0b6cd60..309d26c5d74 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_en_US.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_en_US.pass.cpp
index 28f7451e909..d6e4d6cc1d9 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_en_US.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_en_US.pass.cpp
@@ -43,7 +43,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_en_US_UTF_8);
@@ -490,4 +490,6 @@ int main()
         assert(ios.width() == 0);
     }
 }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp
index e9e916a3ce5..72f3f65706f 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp
@@ -78,7 +78,7 @@ static std::wstring convert_thousands_sep(std::wstring const& in) {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_fr_FR_UTF_8);
@@ -524,4 +524,6 @@ int main()
         assert(ios.width() == 0);
     }
 }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_ru_RU.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_ru_RU.pass.cpp
index 1894144db62..36f97b1d816 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_ru_RU.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_ru_RU.pass.cpp
@@ -55,7 +55,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_ru_RU_UTF_8);
@@ -501,4 +501,6 @@ int main()
         assert(ios.width() == 0);
     }
 }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_zh_CN.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_zh_CN.pass.cpp
index 0a3d478ec67..a300ba84752 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_zh_CN.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_zh_CN.pass.cpp
@@ -49,7 +49,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_zh_CN_UTF_8);
@@ -495,4 +495,6 @@ int main()
         assert(ios.width() == 0);
     }
 }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_string_en_US.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_string_en_US.pass.cpp
index ab4a5c6034b..cd1ff643f83 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_string_en_US.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_string_en_US.pass.cpp
@@ -43,7 +43,7 @@ public:
         : Fw(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::string loc_name(LOCALE_en_US_UTF_8);
@@ -490,4 +490,6 @@ int main()
         assert(ios.width() == 0);
     }
 }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/types.pass.cpp
index 27c2ff5d6b3..bd797313c85 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <locale>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::money_put<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::money_put<wchar_t> >::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::money_put<wchar_t>::iter_type, std::ostreambuf_iterator<wchar_t> >::value), "");
     static_assert((std::is_same<std::money_put<char>::string_type, std::string>::value), "");
     static_assert((std::is_same<std::money_put<wchar_t>::string_type, std::wstring>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/curr_symbol.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/curr_symbol.pass.cpp
index f04ff4fb614..43a2fbc173d 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/curr_symbol.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/curr_symbol.pass.cpp
@@ -75,7 +75,7 @@ static bool glibc_version_less_than(char const* version) {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -179,4 +179,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.curr_symbol() == L"CNY ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/decimal_point.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/decimal_point.pass.cpp
index a64388ca5ce..bec52e6abc0 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/decimal_point.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/decimal_point.pass.cpp
@@ -56,7 +56,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -153,4 +153,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.decimal_point() == L'.');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/frac_digits.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/frac_digits.pass.cpp
index 9bbc76868a8..07d78229a4f 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/frac_digits.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/frac_digits.pass.cpp
@@ -55,7 +55,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -141,4 +141,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.frac_digits() == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/grouping.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/grouping.pass.cpp
index 7ff50db737f..2c2da48642e 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/grouping.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/grouping.pass.cpp
@@ -60,7 +60,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     // Monetary grouping strings may be terminated with 0 or CHAR_MAX, defining
     // how the grouping is repeated.
@@ -149,4 +149,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.grouping() == "\3");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/neg_format.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/neg_format.pass.cpp
index 6cd00de657c..f3f637b60df 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/neg_format.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/neg_format.pass.cpp
@@ -60,7 +60,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -226,4 +226,6 @@ int main()
         assert(p.field[2] == std::money_base::none);
         assert(p.field[3] == std::money_base::value);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/negative_sign.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/negative_sign.pass.cpp
index 6857810bd03..5567fc08eb5 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/negative_sign.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/negative_sign.pass.cpp
@@ -55,7 +55,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -141,4 +141,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.negative_sign() == L"-");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/pos_format.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/pos_format.pass.cpp
index ff3cdcdb2fd..f7d396a6625 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/pos_format.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/pos_format.pass.cpp
@@ -60,7 +60,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -226,4 +226,6 @@ int main()
         assert(p.field[2] == std::money_base::none);
         assert(p.field[3] == std::money_base::value);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/positive_sign.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/positive_sign.pass.cpp
index 50a7ca939ba..43dfa2a2f18 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/positive_sign.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/positive_sign.pass.cpp
@@ -55,7 +55,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -141,4 +141,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.positive_sign() == L"");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp
index e0bfd88a8bf..c789c4e5b1b 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp
@@ -59,7 +59,7 @@ public:
         : std::moneypunct_byname<wchar_t, true>(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f("C", 1);
@@ -170,4 +170,6 @@ int main()
         Fwt f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.thousands_sep() == L',');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/ctor.pass.cpp
index 4717d4c0f1d..3b52f7afc74 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/curr_symbol.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/curr_symbol.pass.cpp
index 57732242586..7b3b75a19c2 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/curr_symbol.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/curr_symbol.pass.cpp
@@ -53,7 +53,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -71,4 +71,6 @@ int main()
         Fwt f(1);
         assert(f.curr_symbol() == std::wstring());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/decimal_point.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/decimal_point.pass.cpp
index 206f325354d..34d02032cc9 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/decimal_point.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/decimal_point.pass.cpp
@@ -53,7 +53,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -71,4 +71,6 @@ int main()
         Fwt f(1);
         assert(f.decimal_point() == std::numeric_limits<wchar_t>::max());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/frac_digits.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/frac_digits.pass.cpp
index b27ecd6df9f..50365584d24 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/frac_digits.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/frac_digits.pass.cpp
@@ -53,7 +53,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -71,4 +71,6 @@ int main()
         Fwt f(1);
         assert(f.frac_digits() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/grouping.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/grouping.pass.cpp
index e959ad8abad..9e12e322044 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/grouping.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/grouping.pass.cpp
@@ -53,7 +53,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -71,4 +71,6 @@ int main()
         Fwt f(1);
         assert(f.grouping() == std::string());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/neg_format.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/neg_format.pass.cpp
index e9950b1a78e..cb511990959 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/neg_format.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/neg_format.pass.cpp
@@ -50,7 +50,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -84,4 +84,6 @@ int main()
         assert(p.field[2] == std::money_base::none);
         assert(p.field[3] == std::money_base::value);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/negative_sign.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/negative_sign.pass.cpp
index 3ef5e84fc05..6f134e7847e 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/negative_sign.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/negative_sign.pass.cpp
@@ -54,7 +54,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -72,4 +72,6 @@ int main()
         Fwt f(1);
         assert(f.negative_sign() == L"-");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/pos_format.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/pos_format.pass.cpp
index 3c3034bbe9d..bff44a69d88 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/pos_format.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/pos_format.pass.cpp
@@ -50,7 +50,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -84,4 +84,6 @@ int main()
         assert(p.field[2] == std::money_base::none);
         assert(p.field[3] == std::money_base::value);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/positive_sign.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/positive_sign.pass.cpp
index dbe3e4ba786..8686e20051b 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/positive_sign.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/positive_sign.pass.cpp
@@ -53,7 +53,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -71,4 +71,6 @@ int main()
         Fwt f(1);
         assert(f.positive_sign() == std::wstring());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/thousands_sep.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/thousands_sep.pass.cpp
index 7b24c6dc9ed..42d28d09656 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/thousands_sep.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.members/thousands_sep.pass.cpp
@@ -53,7 +53,7 @@ public:
         : std::moneypunct<wchar_t, true>(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         Fnf f(1);
@@ -71,4 +71,6 @@ int main()
         Fwt f(1);
         assert(f.thousands_sep() == std::numeric_limits<wchar_t>::max());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/locale.moneypunct.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp
index d02c3b43e8a..58f04905a0a 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/money_base.pass.cpp
@@ -18,7 +18,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::money_base mb; ((void)mb);
     static_assert(std::money_base::none == 0, "");
@@ -29,4 +29,6 @@ int main()
     static_assert(sizeof(std::money_base::pattern) == 4, "");
     std::money_base::pattern p;
     p.field[0] = std::money_base::none;
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/types.pass.cpp
index 439f8c31f73..24ddadfb3a7 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct/types.pass.cpp
@@ -29,7 +29,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::moneypunct<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::moneypunct<wchar_t> >::value), "");
@@ -44,4 +44,6 @@ int main()
     test(std::moneypunct<char, true>::intl);
     test(std::moneypunct<wchar_t, false>::intl);
     test(std::moneypunct<wchar_t, true>::intl);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.monetary/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/ctor.pass.cpp
index afb58d5e214..5a3af4b9536 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_bool.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_bool.pass.cpp
index 0c71a735473..79aa68dde8b 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_bool.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_bool.pass.cpp
@@ -39,7 +39,7 @@ protected:
     virtual string_type do_falsename() const {return "no";}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     {
@@ -96,4 +96,6 @@ int main()
             assert(ex == "yes");
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_double.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_double.pass.cpp
index 0d30bbf7096..062d5cfd404 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_double.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_double.pass.cpp
@@ -17876,7 +17876,7 @@ void test8()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -17886,4 +17886,6 @@ int main()
     test6();
     test7();
     test8();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp
index 5cf9bfa1f7a..1aee8bdfe86 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp
@@ -39,7 +39,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     {
@@ -340,4 +340,6 @@ int main()
         assert(ex == "-***1_00_0");
         assert(ios.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_double.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_double.pass.cpp
index 5fcc0e4646b..3e71a1dfbfb 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_double.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_double.pass.cpp
@@ -26206,7 +26206,7 @@ void test12()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -26246,4 +26246,6 @@ int main()
     {
         long double v = std::nan(""); ((void)v);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_long.pass.cpp
index 18d96754be7..a3c49d36ae6 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long_long.pass.cpp
@@ -39,7 +39,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     {
@@ -340,4 +340,6 @@ int main()
         assert(ex == "-***1_00_0");
         assert(ios.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_pointer.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_pointer.pass.cpp
index f4fdf762067..d366c3842bf 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_pointer.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_pointer.pass.cpp
@@ -28,7 +28,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     {
@@ -45,4 +45,6 @@ int main()
         assert(rc > 0);
         assert(ex == expected_str);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp
index 98aba106cc1..420d22fb028 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp
@@ -39,7 +39,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     {
@@ -343,4 +343,6 @@ int main()
                                                  : "18_446_744_073_709_550_61_6"));
         assert(ios.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long_long.pass.cpp
index ccebb6ce1a4..1ad3065c074 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long_long.pass.cpp
@@ -39,7 +39,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     {
@@ -340,4 +340,6 @@ int main()
         assert(ex == "18_446_744_073_709_550_61_6");
         assert(ios.width() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/types.pass.cpp
index 19e8ceeb025..6011c75c1fe 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.nm.put/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::num_put<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::num_put<wchar_t> >::value), "");
@@ -28,4 +28,6 @@ int main()
     static_assert((std::is_same<std::num_put<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::num_put<char>::iter_type, std::ostreambuf_iterator<char> >::value), "");
     static_assert((std::is_same<std::num_put<wchar_t>::iter_type, std::ostreambuf_iterator<wchar_t> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/ctor.pass.cpp
index 2929fb05e1f..096939d0842 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_bool.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_bool.pass.cpp
index 8b4a33e8471..b577d96b73c 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_bool.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_bool.pass.cpp
@@ -51,7 +51,7 @@ protected:
     virtual string_type do_falsename() const {return "ab";}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -226,4 +226,6 @@ int main()
         assert(err == ios.goodbit);
         assert(b == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp
index 7e896f705c0..3980d488d96 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp
@@ -48,7 +48,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -278,4 +278,6 @@ int main()
         assert(err == ios.goodbit);
         assert(std::abs(v - 3.14159265358979e+10)/3.14159265358979e+10 < 1.e-8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp
index aa7ffcb7809..1ac313f7d7a 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp
@@ -35,7 +35,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -208,4 +208,6 @@ int main()
         assert(err == ios.goodbit);
         assert(v == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long.pass.cpp
index 02f2ba6dcb1..13511728678 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long.pass.cpp
@@ -41,7 +41,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -517,4 +517,6 @@ int main()
         assert(err == ios.failbit);
         assert(v == std::numeric_limits<long>::max());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp
index 89fa436a909..49e8ae750d9 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp
@@ -35,7 +35,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -267,4 +267,6 @@ int main()
         assert(err == ios.goodbit);
         assert(v == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_long.pass.cpp
index 9f8153c6b28..c3a66a9836a 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_long.pass.cpp
@@ -40,7 +40,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -102,4 +102,6 @@ int main()
         const long long expect = 0x8000000000000000LL;
         assert(v == expect);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_pointer.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_pointer.pass.cpp
index 2388dce5fb7..23b6ad932d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_pointer.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_pointer.pass.cpp
@@ -29,7 +29,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -57,4 +57,6 @@ int main()
         assert(err == ios.goodbit);
         assert(p == (void*)0x73);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_int.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_int.pass.cpp
index 36aafc2f484..8a1ee3914f7 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_int.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_int.pass.cpp
@@ -40,7 +40,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -79,4 +79,6 @@ int main()
         assert(err == ios.goodbit);
         assert(v == 0xFFFFFFFF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long.pass.cpp
index 47b58b34eed..e97c460c7e4 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long.pass.cpp
@@ -40,7 +40,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -79,4 +79,6 @@ int main()
         assert(err == ios.goodbit);
         assert(v == 0xFFFFFFFF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long_long.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long_long.pass.cpp
index 3518c30a038..a5d57df05cc 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long_long.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_long_long.pass.cpp
@@ -40,7 +40,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -79,4 +79,6 @@ int main()
         assert(err == ios.goodbit);
         assert(v == 0xFFFFFFFFFFFFFFFFULL);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_short.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_short.pass.cpp
index f83148a1d50..261cac3725f 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_short.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_unsigned_short.pass.cpp
@@ -40,7 +40,7 @@ protected:
     virtual std::string do_grouping() const {return std::string("\1\2\3");}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -79,4 +79,6 @@ int main()
         assert(err == ios.goodbit);
         assert(v == 0xFFFF);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_min_max.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_min_max.pass.cpp
index 5c6de9709b2..92cbeda61bb 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_min_max.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_min_max.pass.cpp
@@ -51,7 +51,7 @@ void check_limits()
     }
 }
 
-int main()
+int main(int, char**)
 {
     check_limits<short>();
     check_limits<unsigned short>();
@@ -61,4 +61,6 @@ int main()
     check_limits<unsigned long>();
     check_limits<long long>();
     check_limits<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_neg_one.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_neg_one.pass.cpp
index 4faa4155e48..07a22cb6e55 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_neg_one.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/test_neg_one.pass.cpp
@@ -148,7 +148,7 @@ void test_negate() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_neg_one<long>();
     test_neg_one<long long>();
@@ -161,4 +161,6 @@ int main()
     test_negate<unsigned int>();
     test_negate<unsigned long>();
     test_negate<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/types.pass.cpp
index ab8c00edeb6..42f210d3958 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::num_get<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::num_get<wchar_t> >::value), "");
@@ -28,4 +28,6 @@ int main()
     static_assert((std::is_same<std::num_get<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::num_get<char>::iter_type, std::istreambuf_iterator<char> >::value), "");
     static_assert((std::is_same<std::num_get<wchar_t>::iter_type, std::istreambuf_iterator<wchar_t> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order.pass.cpp
index b779be50f47..30624ecc891 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order.pass.cpp
@@ -33,7 +33,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const my_facet f(LOCALE_en_US_UTF_8, 1);
@@ -51,4 +51,6 @@ int main()
         const my_facet f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.date_order() == std::time_base::ymd);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order_wide.pass.cpp
index 62ca1978488..d62071b94e2 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/date_order_wide.pass.cpp
@@ -33,7 +33,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const my_facet f(LOCALE_en_US_UTF_8, 1);
@@ -51,4 +51,6 @@ int main()
         const my_facet f(LOCALE_zh_CN_UTF_8, 1);
         assert(f.date_order() == std::time_base::ymd);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date.pass.cpp
index 5c0a5ff59a2..e5b5913256d 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date.pass.cpp
@@ -44,7 +44,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -98,4 +98,6 @@ int main()
         assert(t.tm_year == 109);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date_wide.pass.cpp
index 7dd82ed63ac..5506e4cace8 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_date_wide.pass.cpp
@@ -44,7 +44,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -97,4 +97,6 @@ int main()
         assert(t.tm_year == 109);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname.pass.cpp
index 787d4a00e9f..5311a856508 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname.pass.cpp
@@ -36,7 +36,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -71,4 +71,6 @@ int main()
         assert(t.tm_mon == 5);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname_wide.pass.cpp
index a975bc96293..e45260a6690 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_monthname_wide.pass.cpp
@@ -45,7 +45,7 @@ public:
         : F2(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -80,4 +80,6 @@ int main()
         assert(t.tm_mon == 5);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one.pass.cpp
index c63fab2aa74..bda40c56d27 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one.pass.cpp
@@ -42,7 +42,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -167,4 +167,6 @@ int main()
         assert(t.tm_hour == 23);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one_wide.pass.cpp
index 6c8d86e12ac..d8715f825d0 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_one_wide.pass.cpp
@@ -42,7 +42,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -169,4 +169,6 @@ int main()
         assert(t.tm_hour == 23);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time.pass.cpp
index bdb61c66d81..a007415d034 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time.pass.cpp
@@ -37,7 +37,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -90,4 +90,6 @@ int main()
         assert(t.tm_sec == 15);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time_wide.pass.cpp
index b0e8b1c39c5..0e2481d6a84 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_time_wide.pass.cpp
@@ -37,7 +37,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -90,4 +90,6 @@ int main()
         assert(t.tm_sec == 15);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday.pass.cpp
index 342c87a48bf..308b08529ea 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday.pass.cpp
@@ -40,7 +40,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -87,4 +87,6 @@ int main()
         assert(t.tm_wday == 1);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday_wide.pass.cpp
index c2566095f73..c52462e37c2 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_weekday_wide.pass.cpp
@@ -40,7 +40,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -85,4 +85,6 @@ int main()
         assert(t.tm_wday == 1);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year.pass.cpp
index a53cd059b98..09df423719a 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year.pass.cpp
@@ -36,7 +36,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -81,4 +81,6 @@ int main()
         assert(t.tm_year == 109);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year_wide.pass.cpp
index 93ae51e5559..78c35e969bd 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get.byname/get_year_wide.pass.cpp
@@ -36,7 +36,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     std::ios ios(0);
     std::ios_base::iostate err;
@@ -81,4 +81,6 @@ int main()
         assert(t.tm_year == 109);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/ctor.pass.cpp
index a920c5cb903..6fb9899de7b 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/date_order.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/date_order.pass.cpp
index e14d1c57f37..47b06e9df04 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/date_order.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/date_order.pass.cpp
@@ -26,8 +26,10 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     assert(f.date_order() == std::time_base::mdy);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date.pass.cpp
index 3f95fd3b4cb..1a1dae754f0 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -47,4 +47,6 @@ int main()
         assert(t.tm_year == 105);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date_wide.pass.cpp
index e7f19a5dad2..1fe184bea2f 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_date_wide.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -47,4 +47,6 @@ int main()
         assert(t.tm_year == 105);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_many.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_many.pass.cpp
index 22b2825c865..2416f6275d7 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_many.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_many.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -64,4 +64,6 @@ int main()
         assert(t.tm_min == 27);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname.pass.cpp
index e7b86c79106..8e61dcca876 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -261,4 +261,6 @@ int main()
         assert(t.tm_mon == 0);
         assert(err == std::ios_base::failbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname_wide.pass.cpp
index 78d32ece4f1..a8eb4864ecb 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_monthname_wide.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -261,4 +261,6 @@ int main()
         assert(t.tm_mon == 0);
         assert(err == std::ios_base::failbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_one.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_one.pass.cpp
index fb8b4980817..0c6d9085b57 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_one.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_one.pass.cpp
@@ -29,7 +29,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -301,4 +301,6 @@ int main()
         assert(i.base() == in+sizeof(in)-1);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time.pass.cpp
index c2523dc5d2e..ca0227973dd 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -113,4 +113,6 @@ int main()
 //         assert(t.tm_sec == 0);
         assert(err == std::ios_base::failbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time_wide.pass.cpp
index f78359c918b..98f2a8570ef 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_time_wide.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -113,4 +113,6 @@ int main()
 //         assert(t.tm_sec == 0);
         assert(err == std::ios_base::failbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday.pass.cpp
index f972a63bf20..16e853a4991 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -216,4 +216,6 @@ int main()
         assert(t.tm_wday == 6);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday_wide.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday_wide.pass.cpp
index 3e6e982bd8a..3b7b4e9d83b 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday_wide.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday_wide.pass.cpp
@@ -30,7 +30,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -216,4 +216,6 @@ int main()
         assert(t.tm_wday == 6);
         assert(err == std::ios_base::eofbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_year.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_year.pass.cpp
index 210112f8e30..8a0b8405914 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_year.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_year.pass.cpp
@@ -29,7 +29,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     std::ios ios(0);
@@ -134,4 +134,6 @@ int main()
         assert(t.tm_year == 1099);
         assert(err == std::ios_base::goodbit);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/locale.time.get.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp
index c046a7de6ce..c1b509b40d5 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp
@@ -17,7 +17,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::time_base::dateorder d = std::time_base::no_order;
     ((void)d); // Prevent unused warning
@@ -26,4 +26,6 @@ int main()
     assert(std::time_base::mdy == 2);
     assert(std::time_base::ymd == 3);
     assert(std::time_base::ydm == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/types.pass.cpp
index ba0dd69e452..bd74f7da8e6 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.get/types.pass.cpp
@@ -27,7 +27,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::time_get<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::time_get<wchar_t> >::value), "");
@@ -37,4 +37,6 @@ int main()
     static_assert((std::is_same<std::time_get<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::time_get<char>::iter_type, std::istreambuf_iterator<char> >::value), "");
     static_assert((std::is_same<std::time_get<wchar_t>::iter_type, std::istreambuf_iterator<wchar_t> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put.byname/put1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put.byname/put1.pass.cpp
index 30f1eef6e8f..cd70133274e 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put.byname/put1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put.byname/put1.pass.cpp
@@ -45,7 +45,7 @@ public:
         : F(nm, refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     char str[200];
     output_iterator<char*> iter;
@@ -77,4 +77,6 @@ int main()
         assert((ex == "Today is Samedi which is abbreviated Sam.")||
                (ex == "Today is samedi which is abbreviated sam." ));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/ctor.pass.cpp
index 2010ef4ffd8..9d0ec1ad718 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/ctor.pass.cpp
@@ -31,7 +31,7 @@ public:
 
 int my_facet::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet);
@@ -48,4 +48,6 @@ int main()
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put1.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put1.pass.cpp
index 24971f48f7c..94faa80f1ef 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put1.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put1.pass.cpp
@@ -27,7 +27,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     char str[200];
@@ -57,4 +57,6 @@ int main()
         std::string ex(str, iter.base());
         assert(ex == "The number of the month is 05.");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put2.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put2.pass.cpp
index 9bef3e787c4..a3b6cf5b25c 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put2.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put2.pass.cpp
@@ -27,7 +27,7 @@ public:
         : F(refs) {}
 };
 
-int main()
+int main(int, char**)
 {
     const my_facet f(1);
     char str[200];
@@ -328,4 +328,6 @@ int main()
         std::string ex(str, iter.base());
         assert(ex == "%");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/locale.time.put.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/types.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/types.pass.cpp
index c638624d0bb..4361094f4b0 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/locale.time.put/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::locale::facet, std::time_put<char> >::value), "");
     static_assert((std::is_base_of<std::locale::facet, std::time_put<wchar_t> >::value), "");
@@ -28,4 +28,6 @@ int main()
     static_assert((std::is_same<std::time_put<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::time_put<char>::iter_type, std::ostreambuf_iterator<char> >::value), "");
     static_assert((std::is_same<std::time_put<wchar_t>::iter_type, std::ostreambuf_iterator<wchar_t> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.time/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/category.time/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/category.time/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.time/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/decimal_point.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/decimal_point.pass.cpp
index cddc1497e90..f8132872d4c 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/decimal_point.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/decimal_point.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l("C");
@@ -61,4 +61,6 @@ int main()
             assert(np.decimal_point() == L',');
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/grouping.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/grouping.pass.cpp
index c6e67dbfb27..4dbc7e7b8f2 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/grouping.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/grouping.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l("C");
@@ -70,4 +70,6 @@ int main()
             assert(np.grouping() == group);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp
index 7d6978a9362..25690024027 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l("C");
@@ -84,4 +84,6 @@ int main()
             assert(np.thousands_sep() == wsep);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/ctor.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/ctor.pass.cpp
index 39d0de2775f..e3a10a5c3a3 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/ctor.pass.cpp
@@ -30,7 +30,7 @@ public:
 
 template <class C> int my_facet<C>::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l(std::locale::classic(), new my_facet<char>);
@@ -62,4 +62,6 @@ int main()
         assert(my_facet<wchar_t>::count == 1);
     }
     assert(my_facet<wchar_t>::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/decimal_point.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/decimal_point.pass.cpp
index 43385c023e8..5322c8a87f1 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/decimal_point.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/decimal_point.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -28,4 +28,6 @@ int main()
         const std::numpunct<C>& np = std::use_facet<std::numpunct<C> >(l);
         assert(np.decimal_point() == L'.');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/falsename.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/falsename.pass.cpp
index 7cbf9b43a0d..d1f20f3bbdb 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/falsename.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/falsename.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -28,4 +28,6 @@ int main()
         const std::numpunct<C>& np = std::use_facet<std::numpunct<C> >(l);
         assert(np.falsename() == std::wstring(L"false"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/grouping.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/grouping.pass.cpp
index 2ce956df73d..4c23c51acde 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/grouping.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/grouping.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -28,4 +28,6 @@ int main()
         const std::numpunct<C>& np = std::use_facet<std::numpunct<C> >(l);
         assert(np.grouping() == std::string());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/thousands_sep.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/thousands_sep.pass.cpp
index cc47edbf23c..2044c98a1df 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/thousands_sep.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/thousands_sep.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -28,4 +28,6 @@ int main()
         const std::numpunct<C>& np = std::use_facet<std::numpunct<C> >(l);
         assert(np.thousands_sep() == L',');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/truename.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/truename.pass.cpp
index 96fb3011d63..359c96bef4e 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/truename.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.members/truename.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -28,4 +28,6 @@ int main()
         const std::numpunct<C>& np = std::use_facet<std::numpunct<C> >(l);
         assert(np.truename() == std::wstring(L"true"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.virtuals/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.virtuals/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.virtuals/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/facet.numpunct.virtuals/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp
index 236d9460d34..212670af402 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l = std::locale::classic();
     {
@@ -46,4 +46,6 @@ int main()
         static_assert((std::is_same<std::numpunct<wchar_t>::string_type, std::wstring>::value), "");
         static_assert((std::is_base_of<std::locale::facet, std::numpunct<wchar_t> >::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/facets.examples/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.categories/facets.examples/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.categories/facets.examples/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facets.examples/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_mode.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_mode.pass.cpp
index 160594850d4..def721c4aac 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_mode.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_mode.pass.cpp
@@ -18,11 +18,13 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::consume_header == 4);
     assert(std::generate_header == 2);
     assert(std::little_endian == 1);
     std::codecvt_mode e = std::consume_header;
     assert(e == 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16.pass.cpp
index 22be9593bd2..a66129610fe 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "count_new.hpp"
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -38,4 +38,6 @@ int main()
         assert(globalMemCounter.checkOutstandingNewNotEq(0));
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_always_noconv.pass.cpp
index 91d95af9a04..6bd37789d30 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_always_noconv.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf16<wchar_t> C;
@@ -41,4 +41,6 @@ int main()
         bool r = c.always_noconv();
         assert(r == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_encoding.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_encoding.pass.cpp
index d3fbea6dc2e..2e8a1833c78 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_encoding.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf16<wchar_t> C;
@@ -41,4 +41,6 @@ int main()
         int r = c.encoding();
         assert(r == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_in.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_in.pass.cpp
index e44783564c1..4ccf933d601 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_in.pass.cpp
@@ -24,7 +24,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf16<char32_t> C;
@@ -735,4 +735,6 @@ int main()
         assert(np == n+2);
         assert(w == 0x56);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_length.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_length.pass.cpp
index 4e6fdf85849..39ecb8f0ea0 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_length.pass.cpp
@@ -22,7 +22,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf16<wchar_t> C;
@@ -445,4 +445,6 @@ int main()
         r = c.length(m, n, n+2, 2);
         assert(r == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_max_length.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_max_length.pass.cpp
index 6422d56797b..fa8c3269ad4 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_max_length.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf16<wchar_t> C;
@@ -59,4 +59,6 @@ int main()
         int r = c.max_length();
         assert(r == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_out.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_out.pass.cpp
index afd1e6ad661..beabf842ec3 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_out.pass.cpp
@@ -346,7 +346,9 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() {
+int main(int, char**) {
   TestHelper<char32_t>::test();
   TestHelper<wchar_t>::test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_unshift.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_unshift.pass.cpp
index 2471ccb1952..2c37e257815 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf16_unshift.pass.cpp
@@ -23,7 +23,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf16<wchar_t> C;
@@ -52,4 +52,6 @@ int main()
         std::codecvt_base::result r = c.unshift(m, n, n+4, np);
         assert(r == std::codecvt_base::noconv);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8.pass.cpp
index f350b62ca6b..450f5250929 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "count_new.hpp"
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -38,4 +38,6 @@ int main()
         assert(globalMemCounter.checkOutstandingNewNotEq(0));
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_always_noconv.pass.cpp
index 167521573bd..7d7ba19be8d 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_always_noconv.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> C;
@@ -41,4 +41,6 @@ int main()
         bool r = c.always_noconv();
         assert(r == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_encoding.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_encoding.pass.cpp
index 324546d9936..d8e689f6235 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_encoding.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> C;
@@ -41,4 +41,6 @@ int main()
         int r = c.encoding();
         assert(r == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_in.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_in.pass.cpp
index 4f5d3d8fbee..611d06305c9 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_in.pass.cpp
@@ -24,7 +24,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<char32_t> C;
@@ -356,4 +356,6 @@ int main()
         assert(np == n+1);
         assert(w == 0x56);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_length.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_length.pass.cpp
index 4b5e096afa9..2df1c96035c 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_length.pass.cpp
@@ -22,7 +22,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> C;
@@ -240,4 +240,6 @@ int main()
         r = c.length(m, n, n+1, 3);
         assert(r == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_max_length.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_max_length.pass.cpp
index a353ad6cf56..57e5f5850c6 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_max_length.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> C;
@@ -59,4 +59,6 @@ int main()
         int r = c.max_length();
         assert(r == 7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_out.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_out.pass.cpp
index 430b5c2548c..f8b56bcb6cf 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_out.pass.cpp
@@ -318,8 +318,10 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() {
+int main(int, char**) {
   TestHelper<wchar_t>::test();
   TestHelper<char32_t>::test();
   TestHelper<char16_t>::test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_unshift.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_unshift.pass.cpp
index 344b3e503cc..a41f997977f 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_unshift.pass.cpp
@@ -23,7 +23,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> C;
@@ -52,4 +52,6 @@ int main()
         std::codecvt_base::result r = c.unshift(m, n, n+4, np);
         assert(r == std::codecvt_base::noconv);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_always_noconv.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_always_noconv.pass.cpp
index 6d658624e09..c7fe09caf13 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_always_noconv.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_always_noconv.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8_utf16<wchar_t> C;
@@ -41,4 +41,6 @@ int main()
         bool r = c.always_noconv();
         assert(r == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_encoding.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_encoding.pass.cpp
index a392c8a25b6..595f7888e1c 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_encoding.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_encoding.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8_utf16<wchar_t> C;
@@ -41,4 +41,6 @@ int main()
         int r = c.encoding();
         assert(r == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_in.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_in.pass.cpp
index aab52fdf12e..482521032af 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_in.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_in.pass.cpp
@@ -234,10 +234,12 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() {
+int main(int, char**) {
 #ifndef _WIN32
   TestHelper<wchar_t>::test();
 #endif
   TestHelper<char32_t>::test();
   TestHelper<char16_t>::test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_length.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_length.pass.cpp
index 172a8734de6..33a4b5f04bd 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_length.pass.cpp
@@ -22,7 +22,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8_utf16<wchar_t> C;
@@ -231,4 +231,6 @@ int main()
         r = c.length(m, n, n+1, 2);
         assert(r == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_max_length.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_max_length.pass.cpp
index 247e0ce207a..5d93d929e56 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_max_length.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_max_length.pass.cpp
@@ -21,7 +21,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8_utf16<wchar_t> C;
@@ -59,4 +59,6 @@ int main()
         int r = c.max_length();
         assert(r == 7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_out.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_out.pass.cpp
index 846df215671..89908eb7756 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_out.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_out.pass.cpp
@@ -299,10 +299,12 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() {
+int main(int, char**) {
 #ifndef _WIN32
   TestHelper<wchar_t>::test();
 #endif
   TestHelper<char32_t>::test();
   TestHelper<char16_t>::test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_unshift.pass.cpp b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_unshift.pass.cpp
index 96139bd5b6b..79b670055d5 100644
--- a/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_unshift.pass.cpp
+++ b/libcxx/test/std/localization/locale.stdcvt/codecvt_utf8_utf16_unshift.pass.cpp
@@ -23,7 +23,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8_utf16<wchar_t> C;
@@ -52,4 +52,6 @@ int main()
         std::codecvt_base::result r = c.unshift(m, n, n+4, np);
         assert(r == std::codecvt_base::noconv);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locale.syn/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locale.syn/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locale.syn/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locale.syn/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isalnum.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isalnum.pass.cpp
index 68b9b9f1b73..2cf9e4b5749 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isalnum.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isalnum.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::isalnum(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert( std::isalnum('f', l));
     assert( std::isalnum('9', l));
     assert(!std::isalnum('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isalpha.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isalpha.pass.cpp
index 0e5a777b315..800c26cb918 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isalpha.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isalpha.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::isalpha(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert( std::isalpha('f', l));
     assert(!std::isalpha('9', l));
     assert(!std::isalpha('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/iscntrl.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/iscntrl.pass.cpp
index afca98b70b9..d5cd4a6b962 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/iscntrl.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/iscntrl.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::iscntrl(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert(!std::iscntrl('f', l));
     assert(!std::iscntrl('9', l));
     assert(!std::iscntrl('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isdigit.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isdigit.pass.cpp
index 35a4540fdd8..2e71bd394ac 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isdigit.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isdigit.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::isdigit(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert(!std::isdigit('f', l));
     assert( std::isdigit('9', l));
     assert(!std::isdigit('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isgraph.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isgraph.pass.cpp
index 3b4d0c55162..406b7cbf973 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isgraph.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isgraph.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::isgraph(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert( std::isgraph('f', l));
     assert( std::isgraph('9', l));
     assert( std::isgraph('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/islower.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/islower.pass.cpp
index 057b7022608..2fc9ece026d 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/islower.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/islower.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::islower(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert( std::islower('f', l));
     assert(!std::islower('9', l));
     assert(!std::islower('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isprint.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isprint.pass.cpp
index 990fc03eb82..36fa16cbc74 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isprint.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isprint.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert( std::isprint(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert( std::isprint('f', l));
     assert( std::isprint('9', l));
     assert( std::isprint('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/ispunct.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/ispunct.pass.cpp
index b9fb94a3c4b..db11337805c 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/ispunct.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/ispunct.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::ispunct(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert(!std::ispunct('f', l));
     assert(!std::ispunct('9', l));
     assert( std::ispunct('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isspace.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isspace.pass.cpp
index b00ba46e630..62e50d2fc25 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isspace.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isspace.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert( std::isspace(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert(!std::isspace('f', l));
     assert(!std::isspace('9', l));
     assert(!std::isspace('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isupper.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isupper.pass.cpp
index c5863beb30e..c986c7cdddc 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isupper.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isupper.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::isupper(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert(!std::isupper('f', l));
     assert(!std::isupper('9', l));
     assert(!std::isupper('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/classification/isxdigit.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/classification/isxdigit.pass.cpp
index 4a77628db94..245f2ed6033 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/classification/isxdigit.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/classification/isxdigit.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(!std::isxdigit(' ', l));
@@ -27,4 +27,6 @@ int main()
     assert( std::isxdigit('f', l));
     assert( std::isxdigit('9', l));
     assert(!std::isxdigit('+', l));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/ctor.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/ctor.pass.cpp
index c16755e20ed..f28abb934e0 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/ctor.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/ctor.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "count_new.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::wbuffer_convert<std::codecvt_utf8<wchar_t> > B;
 #if TEST_STD_VER > 11
@@ -55,4 +55,6 @@ int main()
         assert(globalMemCounter.checkOutstandingNewNotEq(0));
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/overflow.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/overflow.pass.cpp
index 66f95df53c7..7c404288596 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/overflow.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/overflow.pass.cpp
@@ -37,7 +37,7 @@ struct test_buf
     virtual int_type overflow(int_type c = traits_type::eof()) {return base::overflow(c);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ofstream bs("overflow.dat");
@@ -96,4 +96,6 @@ int main()
         assert(f.get() == -1);
     }
     std::remove("overflow.dat");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/pbackfail.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/pbackfail.pass.cpp
index f268f9a2198..dc4144b159c 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/pbackfail.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/pbackfail.pass.cpp
@@ -37,7 +37,7 @@ struct test_buf
     virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream bs("underflow.dat");
@@ -55,4 +55,6 @@ int main()
         assert(f.sbumpc() == L'2');
         assert(f.sgetc() == L'3');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/rdbuf.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/rdbuf.pass.cpp
index ffd5a0df7ab..b58d1d8eb7b 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/rdbuf.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/rdbuf.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::wbuffer_convert<std::codecvt_utf8<wchar_t> > B;
     {
@@ -27,4 +27,6 @@ int main()
         b.rdbuf(s.rdbuf());
         assert(b.rdbuf() == s.rdbuf());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/seekoff.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/seekoff.pass.cpp
index 4494d56c7c3..b50f10cc171 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/seekoff.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/seekoff.pass.cpp
@@ -31,7 +31,7 @@ public:
     ~test_codecvt() {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         wchar_t buf[10];
@@ -54,4 +54,6 @@ int main()
         assert(f.sgetc() == L'l');
     }
     std::remove("seekoff.dat");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/state.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/state.pass.cpp
index 1816ad0c775..0541dbfb93b 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/state.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/state.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::wbuffer_convert<std::codecvt_utf8<wchar_t> > B;
     {
@@ -25,4 +25,6 @@ int main()
         std::mbstate_t s = b.state();
         ((void)s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/test.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/test.pass.cpp
index c22fb6a14a7..e309f3eb650 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/test.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/test.pass.cpp
@@ -15,7 +15,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ofstream bytestream("myfile.txt");
@@ -32,4 +32,6 @@ int main()
         assert(ws == L"Hello");
     }
     std::remove("myfile.txt");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/underflow.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/underflow.pass.cpp
index 523778f237f..6d04935b301 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/underflow.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.buffer/underflow.pass.cpp
@@ -37,7 +37,7 @@ struct test_buf
     virtual int_type underflow() {return base::underflow();}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::ifstream bs("underflow.dat");
@@ -80,4 +80,6 @@ int main()
         assert(f.sbumpc() == 0x4E53);
         assert(f.sbumpc() == test_buf::traits_type::eof());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/tolower.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/tolower.pass.cpp
index 72b939dfb5e..9885dca5357 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/tolower.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/tolower.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(std::tolower(' ', l) == ' ');
@@ -27,4 +27,6 @@ int main()
     assert(std::tolower('f', l) == 'f');
     assert(std::tolower('9', l) == '9');
     assert(std::tolower('+', l) == '+');
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/toupper.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/toupper.pass.cpp
index dbd936529ef..34f675b0592 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/toupper.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.character/toupper.pass.cpp
@@ -13,7 +13,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::locale l;
     assert(std::toupper(' ', l) == ' ');
@@ -27,4 +27,6 @@ int main()
     assert(std::toupper('f', l) == 'F');
     assert(std::toupper('9', l) == '9');
     assert(std::toupper('+', l) == '+');
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/converted.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/converted.pass.cpp
index b52bbc0bbcb..802aaf65d0f 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/converted.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/converted.pass.cpp
@@ -61,4 +61,6 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() { TestHelper<wchar_t>::test(); }
+int main(int, char**) { TestHelper<wchar_t>::test(); 
+  return 0;
+}
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt.pass.cpp
index 578547f8ec2..3efd26fb4ce 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> Codecvt;
@@ -36,4 +36,6 @@ int main()
         static_assert( std::is_constructible<Myconv, Codecvt*>::value, "");
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt_state.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt_state.pass.cpp
index 0e58bc2252e..6e2d5ff5e9c 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt_state.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_codecvt_state.pass.cpp
@@ -16,7 +16,7 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::codecvt_utf8<wchar_t> Codecvt;
@@ -24,4 +24,6 @@ int main()
         Myconv myconv(new Codecvt, std::mbstate_t());
         assert(myconv.converted() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_copy.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_copy.pass.cpp
index c1a874dc251..d035c3160eb 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_copy.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_copy.pass.cpp
@@ -21,10 +21,12 @@
 #include <codecvt>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt_utf8<wchar_t> Codecvt;
     typedef std::wstring_convert<Codecvt> Myconv;
     static_assert(!std::is_copy_constructible<Myconv>::value, "");
     static_assert(!std::is_copy_assignable<Myconv>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_err_string.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_err_string.pass.cpp
index 364cfed80c7..e284c13c062 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_err_string.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/ctor_err_string.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt_utf8<wchar_t> Codecvt;
     typedef std::wstring_convert<Codecvt> Myconv;
@@ -70,4 +70,6 @@ int main()
         std::wstring ws = myconv.from_bytes('\xA5');
         assert(ws == L"wide error");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/from_bytes.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/from_bytes.pass.cpp
index e527f31a1e2..c1a26d05582 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/from_bytes.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/from_bytes.pass.cpp
@@ -68,4 +68,6 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() { TestHelper<wchar_t>::test(); }
+int main(int, char**) { TestHelper<wchar_t>::test(); 
+  return 0;
+}
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/state.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/state.pass.cpp
index 0fb5b9f342f..a7588dc2522 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/state.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/state.pass.cpp
@@ -15,11 +15,13 @@
 #include <locale>
 #include <codecvt>
 
-int main()
+int main(int, char**)
 {
     typedef std::codecvt_utf8<wchar_t> Codecvt;
     typedef std::wstring_convert<Codecvt> Myconv;
     Myconv myconv;
     std::mbstate_t s = myconv.state();
     ((void)s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/to_bytes.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/to_bytes.pass.cpp
index 2e4dce8bd72..397ba6494ee 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/to_bytes.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/to_bytes.pass.cpp
@@ -68,4 +68,6 @@ void TestHelper<CharT, 4>::test() {
   }
 }
 
-int main() { TestHelper<wchar_t>::test(); }
+int main(int, char**) { TestHelper<wchar_t>::test(); 
+  return 0;
+}
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/types.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/types.pass.cpp
index eb67ecffc11..c2dea9a9067 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/types.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/conversions.string/types.pass.cpp
@@ -22,7 +22,7 @@
 #include <locale>
 #include <codecvt>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::wstring_convert<std::codecvt_utf8<wchar_t> > myconv;
@@ -31,4 +31,6 @@ int main()
         static_assert((std::is_same<myconv::state_type, std::mbstate_t>::value), "");
         static_assert((std::is_same<myconv::int_type, std::char_traits<wchar_t>::int_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/conversions/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/conversions/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/conversions/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/conversions/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.convenience/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locales/locale.convenience/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/locale.convenience/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.convenience/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.global.templates/has_facet.pass.cpp b/libcxx/test/std/localization/locales/locale.global.templates/has_facet.pass.cpp
index a895b1aa107..66539d1eaba 100644
--- a/libcxx/test/std/localization/locales/locale.global.templates/has_facet.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.global.templates/has_facet.pass.cpp
@@ -21,11 +21,13 @@ struct my_facet
 
 std::locale::id my_facet::id;
 
-int main()
+int main(int, char**)
 {
     std::locale loc;
     assert(std::has_facet<std::ctype<char> >(loc));
     assert(!std::has_facet<my_facet>(loc));
     std::locale loc2(loc, new my_facet);
     assert(std::has_facet<my_facet>(loc2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale.global.templates/use_facet.pass.cpp b/libcxx/test/std/localization/locales/locale.global.templates/use_facet.pass.cpp
index c7f53975d3a..3c2cb604232 100644
--- a/libcxx/test/std/localization/locales/locale.global.templates/use_facet.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale.global.templates/use_facet.pass.cpp
@@ -30,7 +30,7 @@ struct my_facet
 
 std::locale::id my_facet::id;
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     try
@@ -53,4 +53,6 @@ int main()
         assert(facet_count == 1);
     }
     assert(facet_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/assign.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/assign.pass.cpp
index 02b5f109699..369fee4cb19 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/assign.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/assign.pass.cpp
@@ -56,7 +56,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_ru_RU_UTF_8);
@@ -67,4 +67,6 @@ int main()
         check(loc2);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/char_pointer.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/char_pointer.pass.cpp
index 5424a8b92dd..c324f394c8b 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/char_pointer.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/char_pointer.pass.cpp
@@ -61,7 +61,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_ru_RU_UTF_8);
@@ -94,4 +94,6 @@ int main()
         std::locale ok("");
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/copy.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/copy.pass.cpp
index 885dfea37b7..4f96ab41554 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/copy.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/copy.pass.cpp
@@ -54,7 +54,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_fr_FR_UTF_8);
@@ -64,4 +64,6 @@ int main()
         check(loc2);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/default.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/default.pass.cpp
index 8f79b184233..5c1e922cbfe 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/default.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/default.pass.cpp
@@ -53,7 +53,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     int ok;
     {
@@ -73,4 +73,6 @@ int main()
         assert(globalMemCounter.checkOutstandingNewEq(ok));
     }
     assert(globalMemCounter.checkOutstandingNewEq(ok));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/locale_char_pointer_cat.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/locale_char_pointer_cat.pass.cpp
index d0ccb8a3405..70f2cb92b79 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/locale_char_pointer_cat.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/locale_char_pointer_cat.pass.cpp
@@ -59,7 +59,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_ru_RU_UTF_8);
@@ -68,4 +68,6 @@ int main()
         check(loc2);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/locale_facetptr.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/locale_facetptr.pass.cpp
index 498682f2834..35c06ce5040 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/locale_facetptr.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/locale_facetptr.pass.cpp
@@ -65,7 +65,7 @@ struct my_facet
 
 std::locale::id my_facet::id;
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_ru_RU_UTF_8);
@@ -85,4 +85,6 @@ int main()
         assert(loc == loc2);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/locale_locale_cat.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/locale_locale_cat.pass.cpp
index 79db6f044ca..ba54e85542e 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/locale_locale_cat.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/locale_locale_cat.pass.cpp
@@ -59,7 +59,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_ru_RU_UTF_8);
@@ -68,4 +68,6 @@ int main()
         check(loc2);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/locale_string_cat.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/locale_string_cat.pass.cpp
index 5fdde6c67ff..3cb3aadac97 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/locale_string_cat.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/locale_string_cat.pass.cpp
@@ -60,7 +60,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(LOCALE_ru_RU_UTF_8);
@@ -69,4 +69,6 @@ int main()
         check(loc2);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.cons/string.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.cons/string.pass.cpp
index 449b9fbc2d1..55b2f88c2be 100644
--- a/libcxx/test/std/localization/locales/locale/locale.cons/string.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.cons/string.pass.cpp
@@ -55,7 +55,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc(std::string(LOCALE_ru_RU_UTF_8));
@@ -69,4 +69,6 @@ int main()
         assert(loc != loc3);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.members/combine.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.members/combine.pass.cpp
index 1a867fbfa6c..fc1f3d33bef 100644
--- a/libcxx/test/std/localization/locales/locale/locale.members/combine.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.members/combine.pass.cpp
@@ -63,7 +63,7 @@ struct my_facet
 
 std::locale::id my_facet::id;
 
-int main()
+int main(int, char**)
 {
 {
     {
@@ -95,4 +95,6 @@ int main()
     assert(globalMemCounter.checkOutstandingNewEq(0));
 }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.members/name.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.members/name.pass.cpp
index 3a6e1b98c53..96ebdf39147 100644
--- a/libcxx/test/std/localization/locales/locale/locale.members/name.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.members/name.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::locale loc;
@@ -27,4 +27,6 @@ int main()
         std::locale loc(LOCALE_en_US_UTF_8);
         assert(loc.name() == LOCALE_en_US_UTF_8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.operators/compare.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.operators/compare.pass.cpp
index b42e55ff67c..ea083d1370d 100644
--- a/libcxx/test/std/localization/locales/locale/locale.operators/compare.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.operators/compare.pass.cpp
@@ -15,7 +15,7 @@
 #include <locale>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::locale l;
@@ -30,4 +30,6 @@ int main()
             assert(l(s3, s2));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.operators/eq.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.operators/eq.pass.cpp
index aeb87708615..1efb487bc8d 100644
--- a/libcxx/test/std/localization/locales/locale/locale.operators/eq.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.operators/eq.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     std::locale cloc;
     std::locale copy(cloc);
@@ -82,4 +82,6 @@ int main()
     assert(noname2 != noname1);
     assert(noname2 != nonamec);
     assert(noname2 == noname2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.statics/classic.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.statics/classic.pass.cpp
index 9060ae27d7a..7594edcc2c6 100644
--- a/libcxx/test/std/localization/locales/locale/locale.statics/classic.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.statics/classic.pass.cpp
@@ -48,11 +48,13 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     std::locale loc = std::locale::classic();
     assert(loc.name() == "C");
     assert(loc == std::locale("C"));
     check(loc);
     check(std::locale("C"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.statics/global.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.statics/global.pass.cpp
index 961bb2f4c47..57f55aa1a76 100644
--- a/libcxx/test/std/localization/locales/locale/locale.statics/global.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.statics/global.pass.cpp
@@ -52,7 +52,7 @@ void check(const std::locale& loc)
     assert((std::has_facet<std::messages<wchar_t> >(loc)));
 }
 
-int main()
+int main(int, char**)
 {
     std::locale loc;
     assert(loc.name() == "C");
@@ -61,4 +61,6 @@ int main()
     std::locale loc2;
     check(loc2);
     assert(loc2 == std::locale(LOCALE_en_US_UTF_8));
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.types/locale.category/category.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.types/locale.category/category.pass.cpp
index 7724ffd00ce..11c3de2975f 100644
--- a/libcxx/test/std/localization/locales/locale/locale.types/locale.category/category.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.types/locale.category/category.pass.cpp
@@ -23,7 +23,7 @@ template <class T>
 void test(const T &) {}
 
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::locale::category, int>::value), "");
     assert(std::locale::none == 0);
@@ -55,4 +55,6 @@ int main()
     test(std::locale::time);
     test(std::locale::messages);
     test(std::locale::all);
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.types/locale.facet/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.types/locale.facet/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/locale/locale.types/locale.facet/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.types/locale.facet/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.types/locale.id/tested_elsewhere.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.types/locale.id/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/locale/locale.types/locale.id/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.types/locale.id/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/locale.types/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locales/locale/locale.types/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/locale/locale.types/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/locale.types/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/locale/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locales/locale/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/locale/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locales/locale/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/locales/nothing_to_do.pass.cpp b/libcxx/test/std/localization/locales/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/locales/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/locales/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/localization/localization.general/nothing_to_do.pass.cpp b/libcxx/test/std/localization/localization.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/localization/localization.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/localization/localization.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/nothing_to_do.pass.cpp b/libcxx/test/std/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/c.math/cmath.pass.cpp b/libcxx/test/std/numerics/c.math/cmath.pass.cpp
index fa904864387..3f9a5f557cc 100644
--- a/libcxx/test/std/numerics/c.math/cmath.pass.cpp
+++ b/libcxx/test/std/numerics/c.math/cmath.pass.cpp
@@ -1514,7 +1514,7 @@ void test_trunc()
     assert(std::trunc(1) == 1);
 }
 
-int main()
+int main(int, char**)
 {
     test_abs();
     test_acos();
@@ -1586,4 +1586,6 @@ int main()
     test_scalbn();
     test_tgamma();
     test_trunc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/c.math/ctgmath.pass.cpp b/libcxx/test/std/numerics/c.math/ctgmath.pass.cpp
index c2ea8e8755d..4cba6031aaf 100644
--- a/libcxx/test/std/numerics/c.math/ctgmath.pass.cpp
+++ b/libcxx/test/std/numerics/c.math/ctgmath.pass.cpp
@@ -10,10 +10,12 @@
 
 #include <ctgmath>
 
-int main()
+int main(int, char**)
 {
     std::complex<double> cd;
     (void)cd;
     double x = std::sin(0);
     ((void)x); // Prevent unused warning
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/c.math/tgmath_h.pass.cpp b/libcxx/test/std/numerics/c.math/tgmath_h.pass.cpp
index c58827cb4af..3fab28b0425 100644
--- a/libcxx/test/std/numerics/c.math/tgmath_h.pass.cpp
+++ b/libcxx/test/std/numerics/c.math/tgmath_h.pass.cpp
@@ -10,6 +10,8 @@
 
 #include <tgmath.h>
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/cfenv/cfenv.syn/cfenv.pass.cpp b/libcxx/test/std/numerics/cfenv/cfenv.syn/cfenv.pass.cpp
index 671e4d12d54..61378439298 100644
--- a/libcxx/test/std/numerics/cfenv/cfenv.syn/cfenv.pass.cpp
+++ b/libcxx/test/std/numerics/cfenv/cfenv.syn/cfenv.pass.cpp
@@ -57,7 +57,7 @@
 #error FE_DFL_ENV not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::fenv_t fenv;
     std::fexcept_t fex;
@@ -74,4 +74,6 @@ int main()
     static_assert((std::is_same<decltype(std::feholdexcept(&fenv)), int>::value), "");
     static_assert((std::is_same<decltype(std::fesetenv(&fenv)), int>::value), "");
     static_assert((std::is_same<decltype(std::feupdateenv(&fenv)), int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/ccmplx/ccomplex.pass.cpp b/libcxx/test/std/numerics/complex.number/ccmplx/ccomplex.pass.cpp
index 4be7122e775..ad1f4c423ac 100644
--- a/libcxx/test/std/numerics/complex.number/ccmplx/ccomplex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/ccmplx/ccomplex.pass.cpp
@@ -10,8 +10,10 @@
 
 #include <ccomplex>
 
-int main()
+int main(int, char**)
 {
     std::complex<double> d;
     (void)d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/UDT_is_rejected.fail.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/UDT_is_rejected.fail.cpp
index 0e9a7cefc55..bc0e5d8142f 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/UDT_is_rejected.fail.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/UDT_is_rejected.fail.cpp
@@ -26,7 +26,7 @@ UDT<long double> ldt;
 UDT<int> it;
 UDT<unsigned long> uit;
 
-int main()
+int main(int, char**)
 {
     {
         std::real(ft); // expected-error {{no matching function}}
@@ -70,4 +70,6 @@ int main()
         std::proj(it); // expected-error {{no matching function}}
         std::proj(uit); // expected-error {{no matching function}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/arg.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/arg.pass.cpp
index f05c42f25ef..bbc865a5ad6 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/arg.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/arg.pass.cpp
@@ -43,7 +43,7 @@ test()
     test<T>(10);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
@@ -51,4 +51,6 @@ int main()
     test<int>();
     test<unsigned>();
     test<long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/conj.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/conj.pass.cpp
index 80bd1571441..46bf69aade5 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/conj.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/conj.pass.cpp
@@ -54,7 +54,7 @@ test()
     test<T>(10);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
@@ -62,4 +62,6 @@ int main()
     test<int>();
     test<unsigned>();
     test<long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/imag.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/imag.pass.cpp
index 8be97fac2a4..a0578127363 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/imag.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/imag.pass.cpp
@@ -56,7 +56,7 @@ test()
     test<T, 10>();
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
@@ -64,4 +64,6 @@ int main()
     test<int>();
     test<unsigned>();
     test<long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/norm.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/norm.pass.cpp
index a3bf9dd27a7..69a2eada84c 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/norm.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/norm.pass.cpp
@@ -43,7 +43,7 @@ test()
     test<T>(10);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
@@ -51,4 +51,6 @@ int main()
     test<int>();
     test<unsigned>();
     test<long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/pow.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/pow.pass.cpp
index 60a5b1957b5..802b9e7735a 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/pow.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/pow.pass.cpp
@@ -78,7 +78,7 @@ test(typename std::enable_if<!std::is_integral<T>::value>::type* = 0, typename s
     test(std::complex<T>(3, 4), std::complex<U>(5, 6));
 }
 
-int main()
+int main(int, char**)
 {
     test<int, float>();
     test<int, double>();
@@ -100,4 +100,6 @@ int main()
 
     test<long double, float>();
     test<long double, double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/proj.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/proj.pass.cpp
index a9dfeae5787..41b82b0d7b9 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/proj.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/proj.pass.cpp
@@ -54,7 +54,7 @@ test()
     test<T>(10);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
@@ -62,4 +62,6 @@ int main()
     test<int>();
     test<unsigned>();
     test<long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/cmplx.over/real.pass.cpp b/libcxx/test/std/numerics/complex.number/cmplx.over/real.pass.cpp
index 5d0fa76b30f..41e9c8fe2d6 100644
--- a/libcxx/test/std/numerics/complex.number/cmplx.over/real.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/cmplx.over/real.pass.cpp
@@ -56,7 +56,7 @@ test()
     test<T, 10>();
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
@@ -64,4 +64,6 @@ int main()
     test<int>();
     test<unsigned>();
     test<long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.literals/literals.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.literals/literals.pass.cpp
index ed944eb04ab..7d8d701fda6 100644
--- a/libcxx/test/std/numerics/complex.number/complex.literals/literals.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.literals/literals.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::complex_literals;
 
@@ -47,4 +47,6 @@ int main()
     auto c2 = 3if;
     assert ( c1 == c2 );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.literals/literals1.fail.cpp b/libcxx/test/std/numerics/complex.number/complex.literals/literals1.fail.cpp
index 0b09858a323..c5e6b29101c 100644
--- a/libcxx/test/std/numerics/complex.number/complex.literals/literals1.fail.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.literals/literals1.fail.cpp
@@ -13,7 +13,9 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::complex<float> foo  = 1.0if;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.literals/literals1.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.literals/literals1.pass.cpp
index 25d0d1d4412..ba9532a5ee3 100644
--- a/libcxx/test/std/numerics/complex.number/complex.literals/literals1.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.literals/literals1.pass.cpp
@@ -13,7 +13,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals;
 
@@ -37,4 +37,6 @@ int main()
     auto c2 = 3if;
     assert ( c1 == c2 );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.literals/literals2.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.literals/literals2.pass.cpp
index 9fbe5572aa6..0b8d2f9cb3f 100644
--- a/libcxx/test/std/numerics/complex.number/complex.literals/literals2.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.literals/literals2.pass.cpp
@@ -13,7 +13,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std;
 
@@ -37,4 +37,6 @@ int main()
     auto c2 = 3if;
     assert ( c1 == c2 );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_complex.pass.cpp
index 8ab5460a0be..d0ccb14f156 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_complex.pass.cpp
@@ -31,7 +31,7 @@ test()
     assert(c.imag() == -4.5);
 }
 
-int main()
+int main(int, char**)
 {
     test<float, float>();
     test<float, double>();
@@ -44,4 +44,6 @@ int main()
     test<long double, float>();
     test<long double, double>();
     test<long double, long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_scalar.pass.cpp
index cb9a778c27c..faab37ea4fd 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_scalar.pass.cpp
@@ -28,9 +28,11 @@ test()
     assert(c.imag() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_complex.pass.cpp
index b1d1288aefa..052c2dceeca 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_complex.pass.cpp
@@ -44,9 +44,11 @@ test()
 
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_scalar.pass.cpp
index 511140c671e..63d34b0512e 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/divide_equal_scalar.pass.cpp
@@ -35,9 +35,11 @@ test()
     assert(c.imag() == 4);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_complex.pass.cpp
index 11c5c319dbd..09cde61241b 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_complex.pass.cpp
@@ -43,9 +43,11 @@ test()
     assert(c3.imag() == -6);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_scalar.pass.cpp
index e3d9da7b50a..ae5b07157de 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/minus_equal_scalar.pass.cpp
@@ -31,9 +31,11 @@ test()
     assert(c.imag() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_complex.pass.cpp
index d108b8a54ef..0c86b6750d3 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_complex.pass.cpp
@@ -43,9 +43,11 @@ test()
     assert(c3.imag() == 6);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_scalar.pass.cpp
index b417505fa08..498724a3627 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/plus_equal_scalar.pass.cpp
@@ -31,9 +31,11 @@ test()
     assert(c.imag() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_complex.pass.cpp
index 1d046908597..fc690072bfa 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_complex.pass.cpp
@@ -43,9 +43,11 @@ test()
     assert(c3.imag() ==   3.5);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_scalar.pass.cpp
index f32b247c2c6..6cb95ea660a 100644
--- a/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.member.ops/times_equal_scalar.pass.cpp
@@ -35,9 +35,11 @@ test()
     assert(c.imag() == 3);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.members/construct.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.members/construct.pass.cpp
index 75d9b5d672f..fa5e5729f40 100644
--- a/libcxx/test/std/numerics/complex.number/complex.members/construct.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.members/construct.pass.cpp
@@ -63,9 +63,11 @@ test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.members/real_imag.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.members/real_imag.pass.cpp
index b1b378b5687..c4a1ef93539 100644
--- a/libcxx/test/std/numerics/complex.number/complex.members/real_imag.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.members/real_imag.pass.cpp
@@ -56,10 +56,12 @@ test()
     test_constexpr<T> ();
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_constexpr<int> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_complex.pass.cpp
index 44837cc09f5..5166fa57ff1 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_complex.pass.cpp
@@ -149,10 +149,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_scalar.pass.cpp
index ec9af0d2131..e7a1d81cf62 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_divide_scalar.pass.cpp
@@ -32,9 +32,11 @@ test()
     test(lhs, rhs, x);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_complex.pass.cpp
index 88cee31584a..27621f165cf 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_complex.pass.cpp
@@ -52,10 +52,12 @@ test()
     test_constexpr<T> ();
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
 //    test_constexpr<int> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_scalar.pass.cpp
index e08d85fd1eb..1ec74e703f1 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_equals_scalar.pass.cpp
@@ -73,10 +73,12 @@ test()
     test_constexpr<T> ();
     }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
 //     test_constexpr<int> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_complex.pass.cpp
index eb93cbe63ee..999a2c91dc0 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_complex.pass.cpp
@@ -40,9 +40,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_scalar.pass.cpp
index 0b81ed949cb..9aea6819c73 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_minus_scalar.pass.cpp
@@ -40,9 +40,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_complex.pass.cpp
index 4ad67be2cc0..319e453a900 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_complex.pass.cpp
@@ -54,10 +54,12 @@ test()
     test_constexpr<T> ();
     }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
 //   test_constexpr<int> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_scalar.pass.cpp
index 43f0f8c5d8f..69c71cde043 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_not_equals_scalar.pass.cpp
@@ -73,10 +73,12 @@ test()
     test_constexpr<T> ();
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
 //     test_constexpr<int> ();
-    }
+    
+  return 0;
+}
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_complex.pass.cpp
index 46953f662d0..5a2fdcfb0da 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_complex.pass.cpp
@@ -40,9 +40,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_scalar.pass.cpp
index 7f4a7a2b59c..4f9dfb1d416 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_plus_scalar.pass.cpp
@@ -40,9 +40,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_complex.pass.cpp
index ba499e51bb2..f2203d4db93 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_complex.pass.cpp
@@ -151,10 +151,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_scalar.pass.cpp
index 94afd4b863f..9fface6b75f 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/complex_times_scalar.pass.cpp
@@ -32,9 +32,11 @@ test()
     test(lhs, rhs, x);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_divide_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_divide_complex.pass.cpp
index e793c7dc95f..01b706dd7b2 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_divide_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_divide_complex.pass.cpp
@@ -32,9 +32,11 @@ test()
     test(lhs, rhs, x);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_equals_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_equals_complex.pass.cpp
index 551fd2574a6..d5dcc29182d 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_equals_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_equals_complex.pass.cpp
@@ -73,10 +73,12 @@ test()
     test_constexpr<T> ();
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
 //     test_constexpr<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_minus_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_minus_complex.pass.cpp
index b693898272e..00657249273 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_minus_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_minus_complex.pass.cpp
@@ -40,9 +40,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_not_equals_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_not_equals_complex.pass.cpp
index 3521814769b..edff47a0160 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_not_equals_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_not_equals_complex.pass.cpp
@@ -73,10 +73,12 @@ test()
     test_constexpr<T> ();
     }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
 //     test_constexpr<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_plus_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_plus_complex.pass.cpp
index 52ae2a15079..d8fc8a6d958 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_plus_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_plus_complex.pass.cpp
@@ -40,9 +40,11 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_times_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_times_complex.pass.cpp
index 1e96a3d9c30..a33347db06a 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/scalar_times_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/scalar_times_complex.pass.cpp
@@ -32,9 +32,11 @@ test()
     test(lhs, rhs, x);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/stream_input.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/stream_input.pass.cpp
index e6d944f42bb..4f33b97ebc8 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/stream_input.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/stream_input.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream is("5");
@@ -95,4 +95,6 @@ int main()
         assert(c == std::complex<double>(-5.5, -6.5));
         assert(!is.eof());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/stream_output.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/stream_output.pass.cpp
index 2e72bd8a5e1..2f1fa91e8dc 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/stream_output.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/stream_output.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::complex<double> c(1, 2);
     std::ostringstream os;
     os << c;
     assert(os.str() == "(1,2)");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/unary_minus.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/unary_minus.pass.cpp
index c61c8779ff1..0249240e830 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/unary_minus.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/unary_minus.pass.cpp
@@ -27,9 +27,11 @@ test()
     assert(c.imag() == -2.5);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.ops/unary_plus.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.ops/unary_plus.pass.cpp
index e6d2de6e45d..c5c2b6de12d 100644
--- a/libcxx/test/std/numerics/complex.number/complex.ops/unary_plus.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.ops/unary_plus.pass.cpp
@@ -27,9 +27,11 @@ test()
     assert(c.imag() == 2.5);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/double_float_explicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/double_float_explicit.pass.cpp
index 9681bdb1766..f2e64466fbd 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/double_float_explicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/double_float_explicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<float> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/double_float_implicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/double_float_implicit.pass.cpp
index db4fb2c4fc8..72a4f024145 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/double_float_implicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/double_float_implicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<float> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_explicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_explicit.pass.cpp
index 09f2b6ae240..751b3b851ea 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_explicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_explicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<long double> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_implicit.fail.cpp b/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_implicit.fail.cpp
index 72031e11e99..51242310a0d 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_implicit.fail.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/double_long_double_implicit.fail.cpp
@@ -17,10 +17,12 @@
 #include <complex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::complex<long double> cd(2.5, 3.5);
     std::complex<double> cf = cd;
     assert(cf.real() == cd.real());
     assert(cf.imag() == cd.imag());
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/float_double_explicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/float_double_explicit.pass.cpp
index e2074cbe366..7ed53c62dfa 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/float_double_explicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/float_double_explicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<double> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/float_double_implicit.fail.cpp b/libcxx/test/std/numerics/complex.number/complex.special/float_double_implicit.fail.cpp
index 66876e0bc9a..7274a2121af 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/float_double_implicit.fail.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/float_double_implicit.fail.cpp
@@ -17,10 +17,12 @@
 #include <complex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::complex<double> cd(2.5, 3.5);
     std::complex<float> cf = cd;
     assert(cf.real() == cd.real());
     assert(cf.imag() == cd.imag());
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_explicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_explicit.pass.cpp
index 5e56346ec1a..b191bf6ea34 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_explicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_explicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<long double> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_implicit.fail.cpp b/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_implicit.fail.cpp
index 6e9bc5b3a31..3bf7a03767e 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_implicit.fail.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/float_long_double_implicit.fail.cpp
@@ -17,10 +17,12 @@
 #include <complex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::complex<long double> cd(2.5, 3.5);
     std::complex<float> cf = cd;
     assert(cf.real() == cd.real());
     assert(cf.imag() == cd.imag());
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_explicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_explicit.pass.cpp
index 3b4ce583929..e257db2bdf1 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_explicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_explicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<double> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_implicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_implicit.pass.cpp
index 5f967668fb3..b47d945fee3 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_implicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/long_double_double_implicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<double> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_explicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_explicit.pass.cpp
index afbea2a0c69..97f91ee0701 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_explicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_explicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<float> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_implicit.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_implicit.pass.cpp
index e6d19736577..51e966d4c1c 100644
--- a/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_implicit.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.special/long_double_float_implicit.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::complex<float> cd(2.5, 3.5);
@@ -35,4 +35,6 @@ int main()
     static_assert(cf.imag() == cd.imag(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.synopsis/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.synopsis/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/complex.number/complex.synopsis/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.synopsis/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/acos.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/acos.pass.cpp
index 76b280af3c6..ecb66968905 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/acos.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/acos.pass.cpp
@@ -129,10 +129,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/acosh.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/acosh.pass.cpp
index b981e1a31d1..4a22dde0287 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/acosh.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/acosh.pass.cpp
@@ -140,10 +140,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/asin.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/asin.pass.cpp
index 7d6516aebae..91ec6e9bdab 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/asin.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/asin.pass.cpp
@@ -108,10 +108,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/asinh.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/asinh.pass.cpp
index c6a6d8bb3cb..18ac1f17a83 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/asinh.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/asinh.pass.cpp
@@ -117,10 +117,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/atan.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/atan.pass.cpp
index f4025ae736f..1816e2f99b0 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/atan.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/atan.pass.cpp
@@ -57,10 +57,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/atanh.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/atanh.pass.cpp
index 4f037377ec6..5e4bb13f5af 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/atanh.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/atanh.pass.cpp
@@ -121,10 +121,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/cos.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/cos.pass.cpp
index ff069397ada..2085a4c85c6 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/cos.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/cos.pass.cpp
@@ -56,10 +56,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/cosh.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/cosh.pass.cpp
index eb6ef8832ed..e95c2968de6 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/cosh.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/cosh.pass.cpp
@@ -106,10 +106,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/exp.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/exp.pass.cpp
index 9442bb08423..fc638d135be 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/exp.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/exp.pass.cpp
@@ -104,10 +104,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/log.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/log.pass.cpp
index 98d3cf45475..35f0c5c41b4 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/log.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/log.pass.cpp
@@ -121,10 +121,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/log10.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/log10.pass.cpp
index 299e037a6ed..676175507c9 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/log10.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/log10.pass.cpp
@@ -55,10 +55,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_complex.pass.cpp
index 8485277927e..d34ab0c7ca1 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_complex.pass.cpp
@@ -60,10 +60,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_scalar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_scalar.pass.cpp
index 55120dcd524..7ffdd6136e6 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_scalar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_complex_scalar.pass.cpp
@@ -58,10 +58,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_scalar_complex.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_scalar_complex.pass.cpp
index 81b4b2ca765..e4b5d3d14b6 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_scalar_complex.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/pow_scalar_complex.pass.cpp
@@ -58,10 +58,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/sin.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/sin.pass.cpp
index 2c2b8cbb923..6e33f705454 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/sin.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/sin.pass.cpp
@@ -57,10 +57,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/sinh.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/sinh.pass.cpp
index a2668320f68..7a9e7989830 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/sinh.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/sinh.pass.cpp
@@ -107,10 +107,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/sqrt.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/sqrt.pass.cpp
index 007bf2ac32d..a0b8433022f 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/sqrt.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/sqrt.pass.cpp
@@ -99,10 +99,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/tan.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/tan.pass.cpp
index e7c80a3095c..b4bc207fccc 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/tan.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/tan.pass.cpp
@@ -58,10 +58,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.transcendentals/tanh.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.transcendentals/tanh.pass.cpp
index 511cdeefae3..1be3a2cd0e7 100644
--- a/libcxx/test/std/numerics/complex.number/complex.transcendentals/tanh.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.transcendentals/tanh.pass.cpp
@@ -89,10 +89,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/abs.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/abs.pass.cpp
index 8fa09a7ef3a..7a518fc378e 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/abs.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/abs.pass.cpp
@@ -53,10 +53,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/arg.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/arg.pass.cpp
index 27366ec0efa..280ccc8cbc4 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/arg.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/arg.pass.cpp
@@ -125,10 +125,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/conj.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/conj.pass.cpp
index 7d6472aa6ee..8c144ffbf2f 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/conj.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/conj.pass.cpp
@@ -32,9 +32,11 @@ test()
     test(std::complex<T>(-1, -2), std::complex<T>(-1, 2));
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/imag.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/imag.pass.cpp
index d4bf0d8c120..fe7cb3a9680 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/imag.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/imag.pass.cpp
@@ -23,9 +23,11 @@ test()
     assert(imag(z) == 2.5);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/norm.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/norm.pass.cpp
index aeb13c80b1e..fe197ff21c2 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/norm.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/norm.pass.cpp
@@ -53,10 +53,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/polar.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/polar.pass.cpp
index 3f7c497c27b..b7450abed68 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/polar.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/polar.pass.cpp
@@ -102,10 +102,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/proj.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/proj.pass.cpp
index 6de4a0af8fa..238429b5520 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/proj.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/proj.pass.cpp
@@ -61,10 +61,12 @@ void test_edges()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
     test_edges();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex.value.ops/real.pass.cpp b/libcxx/test/std/numerics/complex.number/complex.value.ops/real.pass.cpp
index a94ba9f1401..138785900c3 100644
--- a/libcxx/test/std/numerics/complex.number/complex.value.ops/real.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex.value.ops/real.pass.cpp
@@ -23,9 +23,11 @@ test()
     assert(real(z) == 1.5);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/complex/types.pass.cpp b/libcxx/test/std/numerics/complex.number/complex/types.pass.cpp
index 3b2f3f7b85c..517743071dc 100644
--- a/libcxx/test/std/numerics/complex.number/complex/types.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/complex/types.pass.cpp
@@ -27,9 +27,11 @@ test()
     static_assert((std::is_same<typename C::value_type, T>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/complex.number/layout.pass.cpp b/libcxx/test/std/numerics/complex.number/layout.pass.cpp
index a154f5e40ae..bcb81189abc 100644
--- a/libcxx/test/std/numerics/complex.number/layout.pass.cpp
+++ b/libcxx/test/std/numerics/complex.number/layout.pass.cpp
@@ -27,9 +27,11 @@ test()
     assert(a[1] == z.imag());
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.gslice/gslice.access/tested_elsewhere.pass.cpp b/libcxx/test/std/numerics/numarray/class.gslice/gslice.access/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numarray/class.gslice/gslice.access/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.gslice/gslice.access/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/default.pass.cpp b/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/default.pass.cpp
index 854b5cb35f1..312425afbf1 100644
--- a/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/default.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/default.pass.cpp
@@ -15,10 +15,12 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::gslice gs;
     assert(gs.start() == 0);
     assert(gs.size().size() == 0);
     assert(gs.stride().size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/start_size_stride.pass.cpp b/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/start_size_stride.pass.cpp
index 2faff95c7c1..682bb83fd1c 100644
--- a/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/start_size_stride.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.gslice/gslice.cons/start_size_stride.pass.cpp
@@ -16,7 +16,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::size_t a1[] = {1, 2, 3};
     std::size_t a2[] = {4, 5, 6};
@@ -34,4 +34,6 @@ int main()
     assert(r[0] == 4);
     assert(r[1] == 5);
     assert(r[2] == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.gslice/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/numarray/class.gslice/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numarray/class.gslice/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.gslice/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.slice/cons.slice/default.pass.cpp b/libcxx/test/std/numerics/numarray/class.slice/cons.slice/default.pass.cpp
index c03de23437d..92c17b8a2c4 100644
--- a/libcxx/test/std/numerics/numarray/class.slice/cons.slice/default.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.slice/cons.slice/default.pass.cpp
@@ -15,10 +15,12 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::slice s;
     assert(s.start() == 0);
     assert(s.size() == 0);
     assert(s.stride() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.slice/cons.slice/start_size_stride.pass.cpp b/libcxx/test/std/numerics/numarray/class.slice/cons.slice/start_size_stride.pass.cpp
index c74f20d5ad3..72bff975712 100644
--- a/libcxx/test/std/numerics/numarray/class.slice/cons.slice/start_size_stride.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.slice/cons.slice/start_size_stride.pass.cpp
@@ -15,10 +15,12 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::slice s(1, 3, 2);
     assert(s.start() == 1);
     assert(s.size() == 3);
     assert(s.stride() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.slice/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/numarray/class.slice/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numarray/class.slice/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.slice/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/class.slice/slice.access/tested_elsewhere.pass.cpp b/libcxx/test/std/numerics/numarray/class.slice/slice.access/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numarray/class.slice/slice.access/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/class.slice/slice.access/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/default.fail.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/default.fail.cpp
index dbad4eebb32..4429367cf6c 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/default.fail.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/default.fail.cpp
@@ -15,7 +15,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::gslice_array<int> gs;
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/gslice_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/gslice_array.pass.cpp
index a2f0014279b..3a916257b88 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/gslice_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/gslice_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -77,4 +77,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/valarray.pass.cpp
index 147c6e29d12..e1aca3b7ca8 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.assign/valarray.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/addition.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/addition.pass.cpp
index fb1f3b5eeca..9c82a6f9491 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/addition.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/addition.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/and.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/and.pass.cpp
index 4aa5f0245e7..bfe8ab288df 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/and.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/and.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/divide.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/divide.pass.cpp
index 9631d67b0bb..ec54bc4bb90 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/divide.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/divide.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/modulo.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/modulo.pass.cpp
index d74ceaf96d3..63ad3a7778e 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/modulo.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/modulo.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/multiply.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/multiply.pass.cpp
index 9ed9fcd9570..b22fd3015d9 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/multiply.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/multiply.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/or.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/or.pass.cpp
index f6c1007e880..0b068935f91 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/or.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/or.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_left.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_left.pass.cpp
index 92987929e08..912e48acab3 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_left.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_left.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_right.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_right.pass.cpp
index e617158498e..2c8598f7b1d 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_right.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/shift_right.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/subtraction.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/subtraction.pass.cpp
index 6b5075e05f7..8b1271b04c7 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/subtraction.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/subtraction.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/xor.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/xor.pass.cpp
index 285e44cde69..9a981ece829 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/xor.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.comp.assign/xor.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.fill/assign_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.fill/assign_value.pass.cpp
index d3e98707898..c7c09258093 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.fill/assign_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/gslice.array.fill/assign_value.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -70,4 +70,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.gslice.array/types.pass.cpp b/libcxx/test/std/numerics/numarray/template.gslice.array/types.pass.cpp
index 4fcc7717757..9263c0e051f 100644
--- a/libcxx/test/std/numerics/numarray/template.gslice.array/types.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.gslice.array/types.pass.cpp
@@ -17,7 +17,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::gslice_array<int>::value_type, int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/default.fail.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/default.fail.cpp
index 203a9172686..988cdad9048 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/default.fail.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/default.fail.cpp
@@ -15,7 +15,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::indirect_array<int> ia;
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/indirect_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/indirect_array.pass.cpp
index 5b27d5e0a34..c19152bb9bd 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/indirect_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/indirect_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -76,4 +76,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/valarray.pass.cpp
index f3f0a49a4f1..0bc4b58179a 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.assign/valarray.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/addition.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/addition.pass.cpp
index 297b9ed85a9..3ed95f9cb1e 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/addition.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/addition.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/and.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/and.pass.cpp
index 1dcb9c0b1df..00fd2f18da7 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/and.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/and.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/divide.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/divide.pass.cpp
index 1112bca9f56..1a9ca265ad9 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/divide.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/divide.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/modulo.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/modulo.pass.cpp
index 061735a2614..bad0b950e35 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/modulo.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/modulo.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/multiply.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/multiply.pass.cpp
index d64ff33f1d7..7e78f0a8f39 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/multiply.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/multiply.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/or.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/or.pass.cpp
index 11240333ca8..ba32accc64a 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/or.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/or.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_left.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_left.pass.cpp
index 160bb805950..deff80cc3a4 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_left.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_left.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_right.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_right.pass.cpp
index fbebc1a2514..d2ac739541f 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_right.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/shift_right.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/subtraction.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/subtraction.pass.cpp
index 1d4a5bf141e..d94422c0927 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/subtraction.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/subtraction.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/xor.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/xor.pass.cpp
index 0a643445453..06e06682740 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/xor.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.comp.assign/xor.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.fill/assign_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.fill/assign_value.pass.cpp
index d49f2a0f6ac..e327d2630e8 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.fill/assign_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/indirect.array.fill/assign_value.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -70,4 +70,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.indirect.array/types.pass.cpp b/libcxx/test/std/numerics/numarray/template.indirect.array/types.pass.cpp
index 6cc9988aa91..5d06c5baf67 100644
--- a/libcxx/test/std/numerics/numarray/template.indirect.array/types.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.indirect.array/types.pass.cpp
@@ -17,7 +17,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::indirect_array<int>::value_type, int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/default.fail.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/default.fail.cpp
index 5bec2dcad61..f22298bf907 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/default.fail.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/default.fail.cpp
@@ -15,7 +15,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::mask_array<int> s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/mask_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/mask_array.pass.cpp
index d1604055629..22ce22ad62c 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/mask_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/mask_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
@@ -62,4 +62,6 @@ int main()
     std::mask_array<int> const & r = (m1 = m2);
     assert(&r == &m1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/valarray.pass.cpp
index e7e0d3740a7..e364c442ff7 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.assign/valarray.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/addition.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/addition.pass.cpp
index 084a0d11b8c..e8f0958b53c 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/addition.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/addition.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/and.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/and.pass.cpp
index e797343b619..ab2937986c2 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/and.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/and.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/divide.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/divide.pass.cpp
index dc7bbb2f138..cd67632efd0 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/divide.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/divide.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/modulo.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/modulo.pass.cpp
index 302cdcc3e59..7cf8b585d03 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/modulo.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/modulo.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/multiply.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/multiply.pass.cpp
index cfe282203ca..537bf40d8d6 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/multiply.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/multiply.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/or.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/or.pass.cpp
index 2fdfe0de290..d0297b831e8 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/or.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/or.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_left.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_left.pass.cpp
index aaf6f2d43ff..eee4c1d461c 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_left.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_left.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_right.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_right.pass.cpp
index 15d745e0208..b65c19f99c4 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_right.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/shift_right.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/subtraction.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/subtraction.pass.cpp
index 7b09a0ec489..40fddd123a0 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/subtraction.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/subtraction.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/xor.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/xor.pass.cpp
index 5487ea02401..a04b6da2705 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/xor.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.comp.assign/xor.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -45,4 +45,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.fill/assign_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.fill/assign_value.pass.cpp
index 63558d8d535..bb4fd85912b 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.fill/assign_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/mask.array.fill/assign_value.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -41,4 +41,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.mask.array/types.pass.cpp b/libcxx/test/std/numerics/numarray/template.mask.array/types.pass.cpp
index 6848c655b56..1d4acea6f11 100644
--- a/libcxx/test/std/numerics/numarray/template.mask.array/types.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.mask.array/types.pass.cpp
@@ -17,7 +17,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::mask_array<int>::value_type, int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/default.fail.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/default.fail.cpp
index 59f5fdf0ec5..90b1845ba5f 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/default.fail.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/default.fail.cpp
@@ -15,7 +15,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::slice_array<int> s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/slice_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/slice_array.pass.cpp
index 40dc0be7101..9683c7dfbd2 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/slice_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/slice_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
@@ -50,4 +50,6 @@ int main()
     std::slice_array<int> const & s3 = (s1 = s2);
     assert(&s1 == &s3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/valarray.pass.cpp
index 7ea08cfaea9..88a5b44ab24 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/valarray.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == -5);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/addition.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/addition.pass.cpp
index 5934c2015c4..0433877e749 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/addition.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/addition.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] ==  8);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/and.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/and.pass.cpp
index 3af46538bad..90bbe4ef333 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/and.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/and.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {1, 2, 3, 4, 5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] ==  5);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/divide.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/divide.pass.cpp
index 508ebbbd8ca..ae1383b84bd 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/divide.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/divide.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == -2);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/modulo.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/modulo.pass.cpp
index 7b3919e49f0..89c1acfb381 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/modulo.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/modulo.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] ==  3);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/multiply.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/multiply.pass.cpp
index ffcd8542419..b7c6b13530a 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/multiply.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/multiply.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == -65);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/or.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/or.pass.cpp
index b4054423447..0f37579e86d 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/or.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/or.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {1, 2, 3, 4, 5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_left.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_left.pass.cpp
index fcf51bb1857..547a8cd279a 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_left.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_left.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {1, 2, 3, 4, 5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == 416);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_right.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_right.pass.cpp
index 4c79b559b02..99c4ef94311 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_right.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/shift_right.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {1, 2, 3, 4, 5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] ==  0);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/subtraction.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/subtraction.pass.cpp
index aae003cf318..db513bc9629 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/subtraction.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/subtraction.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == 18);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/xor.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/xor.pass.cpp
index afebc882049..4ecba47238e 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/xor.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.comp.assign/xor.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {1, 2, 3, 4, 5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] ==  8);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.fill/assign_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.fill/assign_value.pass.cpp
index ed1b219a654..ab2156b4627 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.fill/assign_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.fill/assign_value.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     std::valarray<int> v1(a1, sizeof(a1)/sizeof(a1[0]));
@@ -37,4 +37,6 @@ int main()
     assert(v1[13] == 20);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.slice.array/types.pass.cpp b/libcxx/test/std/numerics/numarray/template.slice.array/types.pass.cpp
index 0d1989a4847..fccde7edb6b 100644
--- a/libcxx/test/std/numerics/numarray/template.slice.array/types.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.slice.array/types.pass.cpp
@@ -17,7 +17,9 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::slice_array<int>::value_type, int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/types.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/types.pass.cpp
index 301192ef8c9..f37ba0f7717 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/types.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/types.pass.cpp
@@ -18,8 +18,10 @@
 #include <valarray>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::valarray<int>::value_type, int>::value), "");
     static_assert((std::is_same<std::valarray<double>::value_type, double>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/access.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/access.pass.cpp
index dc90dbef9bf..d92154130b8 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/access.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/access.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
             assert(v[i] == static_cast<int>(i));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/const_access.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/const_access.pass.cpp
index a4c81440ed2..a0174ccb3ff 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/const_access.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.access/const_access.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -27,4 +27,6 @@ int main()
             assert(v[i] == a[i]);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
index 24f6cc54bb7..777d922a437 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
@@ -31,7 +31,7 @@ bool operator==(const S& lhs, const S& rhs)
     return lhs.x_ == rhs.x_;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -82,4 +82,6 @@ int main()
             assert(v2[i] == v[i]);
         assert(!S::default_ctor_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/gslice_array_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/gslice_array_assign.pass.cpp
index 625cf17a867..df5ae916225 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/gslice_array_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/gslice_array_assign.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -54,4 +54,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/indirect_array_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/indirect_array_assign.pass.cpp
index 3c351d0b3f9..f8b5243b919 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/indirect_array_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/indirect_array_assign.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -54,4 +54,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
index 4f9b60db642..1f9e5a51f6e 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
@@ -33,7 +33,7 @@ bool operator==(const S& lhs, const S& rhs)
     return lhs.x_ == rhs.x_;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -80,4 +80,6 @@ int main()
             assert(v2[i] == a[i]);
         assert(!S::default_ctor_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/mask_array_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/mask_array_assign.pass.cpp
index 592e306e70c..aeb95a10b74 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/mask_array_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/mask_array_assign.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -31,4 +31,6 @@ int main()
     assert(v2[ 2] ==  4);
     assert(v2[ 3] ==  7);
     assert(v2[ 4] == 11);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/move_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/move_assign.pass.cpp
index 263c093b911..522c0a2a33e 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/move_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/move_assign.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -60,4 +60,6 @@ int main()
                 assert(v2[i][j] == a[i][j]);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/slice_array_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/slice_array_assign.pass.cpp
index 5ccfa2e08d5..68b0e37d410 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/slice_array_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/slice_array_assign.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     std::valarray<int> v1(a, sizeof(a)/sizeof(a[0]));
@@ -27,4 +27,6 @@ int main()
     assert(v[2] == 7);
     assert(v[3] == 10);
     assert(v[4] == 13);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/value_assign.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/value_assign.pass.cpp
index c722f8b1e24..3adb1465cf5 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/value_assign.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.assign/value_assign.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -28,4 +28,6 @@ int main()
         for (std::size_t i = 0; i < v.size(); ++i)
             assert(v[i] == 7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_valarray.pass.cpp
index d6f7c57d53d..60b30715312 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_value.pass.cpp
index 6c37d2bc1bb..28737215041 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/and_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_valarray.pass.cpp
index a5cccdc8695..fdb9975d5d3 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_value.pass.cpp
index bff87ab9566..a309767ffba 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/divide_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_valarray.pass.cpp
index e574de21f03..a8ef9152b00 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_value.pass.cpp
index 0dee79df70f..263ac820a72 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/minus_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_valarray.pass.cpp
index 5dc7ca5cea4..79cfeb0c415 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v2[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_value.pass.cpp
index 0e306cefc22..b0ea0a2986b 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/modulo_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_valarray.pass.cpp
index 97e3b9b994b..df962a044f2 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_value.pass.cpp
index ba44c578df9..1be8942ab7a 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/or_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_valarray.pass.cpp
index 67ed8bc5c0e..3700e5c4758 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_value.pass.cpp
index 730ac7f15d1..c8c5d1ef9c6 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/plus_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_valarray.pass.cpp
index 91ea80ed286..f642ce4316d 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_value.pass.cpp
index abbb0023cc3..8cba6b4dac5 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_left_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_valarray.pass.cpp
index f5fc5c7248a..d50971b394d 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_value.pass.cpp
index 00f5e256026..670599afd34 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/shift_right_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_valarray.pass.cpp
index 00ac963b71e..f7e3da5bf9a 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_value.pass.cpp
index a039f9f8c8b..9632799683b 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/times_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_valarray.pass.cpp
index f9d8ba3b546..bf08055117a 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -33,4 +33,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_value.pass.cpp
index 02c1398244c..0a3d3200f90 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cassign/xor_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -30,4 +30,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == v2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/copy.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/copy.pass.cpp
index a97a250474e..8a9c6baae3a 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/copy.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/copy.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -52,4 +52,6 @@ int main()
                 assert(v2[i][j] == v[i][j]);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
index ff4a7a25444..b5603980244 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
@@ -22,7 +22,7 @@ struct S {
 
 bool S::ctor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         std::valarray<int> v;
@@ -45,4 +45,6 @@ int main()
         assert(v.size() == 0);
         assert(!S::ctor_called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/gslice_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/gslice_array.pass.cpp
index 7e061f50a86..fdab3e3e8e4 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/gslice_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/gslice_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -53,4 +53,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/indirect_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/indirect_array.pass.cpp
index e525b2a4f6a..3a62b0a5479 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/indirect_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/indirect_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -53,4 +53,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/initializer_list.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/initializer_list.pass.cpp
index bd47c57980b..1f5986eda18 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -37,4 +37,6 @@ int main()
         for (unsigned i = 0; i < N; ++i)
             assert(v[i] == a[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/mask_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/mask_array.pass.cpp
index e9deea94a17..4559c36e7ca 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/mask_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/mask_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -30,4 +30,6 @@ int main()
     assert(v2[ 2] ==  4);
     assert(v2[ 3] ==  7);
     assert(v2[ 4] == 11);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/move.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/move.pass.cpp
index 010649a92b8..0ef6f3cee53 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/move.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/move.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -58,4 +58,6 @@ int main()
                 assert(v2[i][j] == a[i][j]);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/pointer_size.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/pointer_size.pass.cpp
index 84d51b035e9..a0b4a31aebe 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/pointer_size.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/pointer_size.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -49,4 +49,6 @@ int main()
                 assert(v[i][j] == a[i][j]);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp
index 7e539d9c21f..95417e58a63 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp
@@ -24,7 +24,7 @@ struct S {
 
 size_t S::cnt_dtor = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::valarray<int> v(100);
@@ -51,4 +51,6 @@ int main()
             assert(v[i].x == 1);
     }
     assert(S::cnt_dtor == 100);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/slice_array.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/slice_array.pass.cpp
index c5667671f3e..332a617153d 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/slice_array.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/slice_array.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     std::valarray<int> v1(a, sizeof(a)/sizeof(a[0]));
@@ -26,4 +26,6 @@ int main()
     assert(v[2] == 7);
     assert(v[3] == 10);
     assert(v[4] == 13);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/value_size.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/value_size.pass.cpp
index 6e43de782bc..03e4add4648 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/value_size.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.cons/value_size.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::valarray<int> v(5, 100);
@@ -35,4 +35,6 @@ int main()
         for (int i = 0; i < 100; ++i)
             assert(v[i].size() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_cref.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_cref.pass.cpp
index 7d4d079231a..65277870aa5 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_cref.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_cref.pass.cpp
@@ -19,7 +19,7 @@ typedef int T;
 
 T f(const T& t) {return t + 5;}
 
-int main()
+int main(int, char**)
 {
     {
         T a1[] = {1, 2, 3, 4,  5,  6,  7,  8,  9, 10};
@@ -47,4 +47,6 @@ int main()
         for (unsigned i = 0; i < N1; ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_value.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_value.pass.cpp
index d43810062f6..fd100b5e54e 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/apply_value.pass.cpp
@@ -19,7 +19,7 @@ typedef int T;
 
 T f(T t) {return t + 5;}
 
-int main()
+int main(int, char**)
 {
     {
         T a1[] = {1, 2, 3, 4,  5,  6,  7,  8,  9, 10};
@@ -47,4 +47,6 @@ int main()
         for (unsigned i = 0; i < N1; ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/cshift.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/cshift.pass.cpp
index 1aa6a3e9abb..14ca081a1e9 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/cshift.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/cshift.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -123,4 +123,6 @@ int main()
         for (unsigned i = 0; i < N1; ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/max.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/max.pass.cpp
index cc80ea8e07f..bdd84c11836 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/max.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/max.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -36,4 +36,6 @@ int main()
         std::valarray<T> v1(a1, N1);
         assert((2*v1).max() == 8.0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/min.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/min.pass.cpp
index 37d8f3a3136..ca04a930853 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/min.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/min.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -36,4 +36,6 @@ int main()
         std::valarray<T> v1(a1, N1);
         assert((2*v1).min() == -6.0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/resize.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/resize.pass.cpp
index 82dd0bd38aa..e92e7420b3c 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/resize.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/resize.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -38,4 +38,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v1[i] == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/shift.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/shift.pass.cpp
index 2be57bff3fd..1a7628eb349 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/shift.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/shift.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -123,4 +123,6 @@ int main()
         for (unsigned i = 0; i < N1; ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/size.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/size.pass.cpp
index 3498cc59cb5..f790627233d 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/size.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/size.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -37,4 +37,6 @@ int main()
         std::valarray<T> v1;
         assert(v1.size() == N1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/sum.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/sum.pass.cpp
index b1c530aa4fe..084f00fb97e 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/sum.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/sum.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -24,4 +24,6 @@ int main()
         std::valarray<T> v1(a1, N1);
         assert(v1.sum() == 16.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/swap.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/swap.pass.cpp
index 23cf807afc2..12a7d8fd8ea 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/swap.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.members/swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -82,4 +82,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == v1_save[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_const.pass.cpp
index 32e6b5561a8..d84309f221e 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -73,4 +73,6 @@ int main()
     assert(v1[38] == 38);
     assert(v1[39] == 39);
     assert(v1[40] == 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_non_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_non_const.pass.cpp
index 12caa6118a2..ac697187806 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_non_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/gslice_non_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -53,4 +53,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_const.pass.cpp
index d210e5120dc..7e5ef154648 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -53,4 +53,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_non_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_non_const.pass.cpp
index 053e9267e72..82a5f14485a 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_non_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/indirect_array_non_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
@@ -54,4 +54,6 @@ int main()
     assert(v[21] == 34);
     assert(v[22] == 35);
     assert(v[23] == 36);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_const.pass.cpp
index 3eaafee7ee8..d689ce9236e 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     std::valarray<int> v1(a1, sizeof(a1)/sizeof(a1[0]));
@@ -26,4 +26,6 @@ int main()
     assert(v2[2] ==  7);
     assert(v2[3] == 10);
     assert(v2[4] == 13);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_non_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_non_const.pass.cpp
index d4cb64cf964..a6c7cb7e884 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_non_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/slice_non_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5};
@@ -39,4 +39,6 @@ int main()
     assert(v1[13] == -5);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_const.pass.cpp
index 77e86ac7312..13cafbccb48 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -30,4 +30,6 @@ int main()
     assert(v2[ 2] ==  4);
     assert(v2[ 3] ==  7);
     assert(v2[ 4] == 11);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_non_const.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_non_const.pass.cpp
index 6ea9e18496d..34b4cfdb5f6 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_non_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.sub/valarray_bool_non_const.pass.cpp
@@ -15,7 +15,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
@@ -31,4 +31,6 @@ int main()
     assert(v2[ 2] ==  4);
     assert(v2[ 3] ==  7);
     assert(v2[ 4] == 11);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
index 8bb23c0b45c..7f31355d0e0 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -52,4 +52,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == ~(2*v[i]));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
index 2827488d275..a89b24d233b 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -62,4 +62,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == -2*v[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
index 64e902146a2..3975510fba7 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -38,4 +38,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == !(2 * v[i]));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp
index 113bb12e96e..b1f7f313f3f 100644
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -62,4 +62,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == +2*v[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_valarray.pass.cpp
index d195f1d248a..3be9074db3c 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_value.pass.cpp
index 4e083bd15d8..4f1bf8ad66b 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_value_valarray.pass.cpp
index 89fdd065a2d..05990124e26 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/and_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_valarray.pass.cpp
index 4b76423ae8c..50c6a14848a 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_value.pass.cpp
index babecfe9967..f5e0b27271a 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_value_valarray.pass.cpp
index 29316e4c7c4..dde6955bbb7 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/divide_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_valarray.pass.cpp
index af78964cace..f1df168b355 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_value.pass.cpp
index e6760c2306a..0ea4f0c1d88 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_value_valarray.pass.cpp
index 1d984be798e..f2131d10e0c 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/minus_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_valarray.pass.cpp
index 948688ba3a0..22d82f4b57e 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_value.pass.cpp
index 101b32d5309..f498e7af588 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_value_valarray.pass.cpp
index dc2ecc0f8d3..fbd407ce29a 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/modulo_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_valarray.pass.cpp
index c01d33a2bd4..f305243d5a5 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_value.pass.cpp
index 328afb2a462..90fa4b4fd02 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_value_valarray.pass.cpp
index e5ca459632e..295dd6bdc5f 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/or_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_valarray.pass.cpp
index c65a7b2a6c6..19a410e4faa 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_value.pass.cpp
index 46b7fbb5591..2aef9c1a174 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_value_valarray.pass.cpp
index 97b7791deda..ba598f62ddc 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/plus_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_valarray.pass.cpp
index 90f9d756c6d..e71fa1056ea 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_value.pass.cpp
index 5136d3fd99a..3945c1bf454 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_value_valarray.pass.cpp
index 697b46db846..93276345210 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_left_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_valarray.pass.cpp
index 4194c191a24..9422d6be871 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_value.pass.cpp
index 4aabb8a941c..8a68f30ca6f 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_value_valarray.pass.cpp
index cccdca18ca4..519fd2b3bd9 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/shift_right_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_valarray.pass.cpp
index c15b794ce35..bc5e7329c8a 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_value.pass.cpp
index 155ea25b580..330f5e0a70b 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_value_valarray.pass.cpp
index b825ad54e1c..4fa8bb2d209 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/times_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_valarray.pass.cpp
index 5e07f5d4466..fd4fb084c0a 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -32,4 +32,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_value.pass.cpp
index bc22ebaddf0..c5082f553c7 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_valarray_value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_value_valarray.pass.cpp
index 14574a10d9f..377f03ed38d 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.binary/xor_value_valarray.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == a2[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_valarray.pass.cpp
index 3e0951b6e2d..3f3ede056ee 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_value.pass.cpp
index 75bce73a249..de5808e5710 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -42,4 +42,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_value_valarray.pass.cpp
index a6cd5e836d6..c73ec1e54cb 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/and_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -42,4 +42,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_valarray.pass.cpp
index 3b43c109740..187126fc8ed 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_value.pass.cpp
index 1bd1fa0e81b..01c04a62c80 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_value_valarray.pass.cpp
index 5fb05f60ae4..b0db6a0d18e 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/equal_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_valarray.pass.cpp
index 6f7678fc7f5..c8de6208aae 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_value.pass.cpp
index f26e946942a..cf568b5307b 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_value_valarray.pass.cpp
index 2c795aae311..c66a60e062c 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_equal_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_valarray.pass.cpp
index 03468763f13..351b662be07 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_value.pass.cpp
index 970f8d8d567..f895b0783b7 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_value_valarray.pass.cpp
index ad30ae42541..a54b770256b 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/greater_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_valarray.pass.cpp
index 86e5553a8cd..c8812f3fd89 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_value.pass.cpp
index d520a21b965..03caf34a60a 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_value_valarray.pass.cpp
index 2055f7554a1..5026b73d4e2 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_equal_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_valarray.pass.cpp
index 0eb137ca07a..59943f912e3 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_value.pass.cpp
index d7d6b7d8b44..9ced4757139 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_value_valarray.pass.cpp
index 34419bdece0..770d5a96f7d 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/less_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_valarray.pass.cpp
index 4daca5332a8..1892a707176 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_value.pass.cpp
index add76d16c00..3cdb8973958 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_value_valarray.pass.cpp
index a3503805140..49ffeda05ae 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/not_equal_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_valarray.pass.cpp
index ef2b1650980..f62cb4f8cc2 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -34,4 +34,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_value.pass.cpp
index 60f14f2bb56..df73f85e398 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_valarray_value.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -42,4 +42,6 @@ int main()
         for (std::size_t i = 0; i < v1.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_value_valarray.pass.cpp
index 0d9a3124e6c..3798acc67d9 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.comparison/or_value_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -42,4 +42,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.special/swap.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.special/swap.pass.cpp
index 47835083721..2200ddfe015 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.special/swap.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.special/swap.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -84,4 +84,6 @@ int main()
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == v1_save[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/abs_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/abs_valarray.pass.cpp
index ff5c7d89a7a..d721c844263 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/abs_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/abs_valarray.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -31,4 +31,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(v3[i] == a3[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/acos_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/acos_valarray.pass.cpp
index bee16abd798..18b5bcb5b6c 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/acos_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/acos_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/asin_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/asin_valarray.pass.cpp
index 4cecd8cace1..9401200e5c7 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/asin_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/asin_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_valarray.pass.cpp
index 7e81821dd44..fcbd63b8317 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -50,4 +50,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_value.pass.cpp
index 3ab73757778..59928d447ea 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_valarray_value.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_value_valarray.pass.cpp
index 07e7894ae14..ed42627d1f9 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan2_value_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan_valarray.pass.cpp
index 567f568a915..7176b9343e5 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/atan_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cos_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cos_valarray.pass.cpp
index 182b8bc3a9f..bc58e4af23c 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cos_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cos_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cosh_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cosh_valarray.pass.cpp
index fb0965bb3b2..b453edd08c8 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cosh_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/cosh_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/exp_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/exp_valarray.pass.cpp
index 3c19e3edfa1..8e95f870410 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/exp_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/exp_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log10_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log10_valarray.pass.cpp
index 70ba211a82a..39514ed6833 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log10_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log10_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log_valarray.pass.cpp
index 3e616a062bb..050d58fa599 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/log_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_valarray.pass.cpp
index 096cd5d322e..93b8a14cbe6 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -50,4 +50,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_value.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_value.pass.cpp
index 902c9f3216f..62c140c04da 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_value.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_valarray_value.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_value_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_value_valarray.pass.cpp
index 39449782330..0c8a76b6dac 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_value_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/pow_value_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sin_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sin_valarray.pass.cpp
index 2cf38b88bda..92d6f4492a5 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sin_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sin_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sinh_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sinh_valarray.pass.cpp
index fa591d0c6e3..190c212ac8b 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sinh_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sinh_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sqrt_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sqrt_valarray.pass.cpp
index eb40e61b314..805bde633e3 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sqrt_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/sqrt_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tan_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tan_valarray.pass.cpp
index 6395ee55079..4f5b69d0884 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tan_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tan_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tanh_valarray.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tanh_valarray.pass.cpp
index 10e0a22be2c..c63696a8380 100644
--- a/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tanh_valarray.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.nonmembers/valarray.transcend/tanh_valarray.pass.cpp
@@ -31,7 +31,7 @@ bool is_about(double x, double y, int p)
     return a == o.str();
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef double T;
@@ -48,4 +48,6 @@ int main()
         for (std::size_t i = 0; i < v3.size(); ++i)
             assert(is_about(v3[i], a3[i], 10));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.range/begin_const.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.range/begin_const.pass.cpp
index db39ab4a1cd..35e5e4206aa 100644
--- a/libcxx/test/std/numerics/numarray/valarray.range/begin_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.range/begin_const.pass.cpp
@@ -17,7 +17,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -26,4 +26,6 @@ int main()
         const std::valarray<T> v(a, N);
         assert(v[0] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.range/begin_non_const.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.range/begin_non_const.pass.cpp
index fb4013dee6a..e0d8e71da26 100644
--- a/libcxx/test/std/numerics/numarray/valarray.range/begin_non_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.range/begin_non_const.pass.cpp
@@ -17,7 +17,7 @@
 #include <valarray>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -27,4 +27,6 @@ int main()
         *begin(v) = 10;
         assert(v[0] == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.range/end_const.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.range/end_const.pass.cpp
index 113216ad067..d1424d3f0c1 100644
--- a/libcxx/test/std/numerics/numarray/valarray.range/end_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.range/end_const.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -28,4 +28,6 @@ int main()
         assert(v[v.size()-1] == 5);
         assert(static_cast<std::size_t>(end(v) - begin(v)) == v.size());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.range/end_non_const.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.range/end_non_const.pass.cpp
index c5d54729aaa..5e1cbd4a805 100644
--- a/libcxx/test/std/numerics/numarray/valarray.range/end_non_const.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.range/end_non_const.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -29,4 +29,6 @@ int main()
         assert(v[v.size()-1] == 10);
         assert(static_cast<std::size_t>(end(v) - begin(v)) == v.size());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/valarray.syn/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/numarray/valarray.syn/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numarray/valarray.syn/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/valarray.syn/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate.pass.cpp b/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate.pass.cpp
index 2a14a7d8e5e..80a048d07ed 100644
--- a/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate.pass.cpp
@@ -42,11 +42,13 @@ test()
     test(Iter(ia), Iter(ia+sa), 10, 31);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*> >();
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*> >();
     test<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate_op.pass.cpp
index a6dc04b2dfa..c7a55b971e6 100644
--- a/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/accumulate/accumulate_op.pass.cpp
@@ -44,11 +44,13 @@ test()
     test(Iter(ia), Iter(ia+sa), 10, 7200);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*> >();
     test<forward_iterator<const int*> >();
     test<bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*> >();
     test<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference.pass.cpp b/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference.pass.cpp
index ac0b1774173..3e043e5cb8f 100644
--- a/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference.pass.cpp
@@ -75,7 +75,7 @@ public:
 
 #endif
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -112,4 +112,6 @@ int main()
     Y y[3] = {Y(1), Y(2), Y(3)};
     std::adjacent_difference(x, x+3, y);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference_op.pass.cpp
index 967ec2ea345..9a10105d049 100644
--- a/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/adjacent.difference/adjacent_difference_op.pass.cpp
@@ -78,7 +78,7 @@ public:
 #endif
 
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -115,4 +115,6 @@ int main()
     Y y[3] = {Y(1), Y(2), Y(3)};
     std::adjacent_difference(x, x+3, y, std::minus<X>());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp b/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp
index 5568e0d805c..447ceb61ed8 100644
--- a/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp
@@ -85,7 +85,7 @@ void basic_tests()
 
 }
 
-int main()
+int main(int, char**)
 {
     basic_tests();
 
@@ -96,4 +96,6 @@ int main()
     test<random_access_iterator<const int*> >();
     test<const int*>();
     test<      int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp
index 78c8325e219..46cb0800b7b 100644
--- a/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp
@@ -59,7 +59,7 @@ test()
         }
 }
 
-int main()
+int main(int, char**)
 {
 //  All the iterator categories
     test<input_iterator        <const int*> >();
@@ -85,4 +85,6 @@ int main()
         assert(res[i] == j);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan.pass.cpp b/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan.pass.cpp
index b02ce5408bf..0ab019c5e00 100644
--- a/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan.pass.cpp
@@ -90,7 +90,7 @@ void basic_tests()
     }
 }
 
-int main()
+int main(int, char**)
 {
     basic_tests();
 
@@ -101,4 +101,6 @@ int main()
     test<random_access_iterator<const int*> >();
     test<const int*>();
     test<      int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op.pass.cpp
index 07561175b10..88633ac84ed 100644
--- a/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op.pass.cpp
@@ -97,7 +97,7 @@ void basic_tests()
 }
 
 
-int main()
+int main(int, char**)
 {
 
     basic_tests();
@@ -110,4 +110,6 @@ int main()
 //     test<const int*>();
 //     test<      int*>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op_init.pass.cpp b/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op_init.pass.cpp
index 06a1874540a..c6e691aeeb8 100644
--- a/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op_init.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op_init.pass.cpp
@@ -113,7 +113,7 @@ void basic_tests()
 }
 
 
-int main()
+int main(int, char**)
 {
 
     basic_tests();
@@ -126,4 +126,6 @@ int main()
     test<const int*>();
     test<      int*>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product.pass.cpp b/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product.pass.cpp
index fec9182b128..fa5c1e8341a 100644
--- a/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product.pass.cpp
@@ -47,7 +47,7 @@ test()
     test(Iter1(a), Iter1(a+sa), Iter2(b), 10, 66);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*> >();
     test<input_iterator<const int*>, forward_iterator<const int*> >();
@@ -78,4 +78,6 @@ int main()
     test<const int*, bidirectional_iterator<const int*> >();
     test<const int*, random_access_iterator<const int*> >();
     test<const int*, const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp b/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp
index d0d152db1ae..e42e3cea915 100644
--- a/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp
@@ -50,7 +50,7 @@ test()
     test(Iter1(a), Iter1(a+sa), Iter2(b), 10, 1176490);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, input_iterator<const int*> >();
     test<input_iterator<const int*>, forward_iterator<const int*> >();
@@ -81,4 +81,6 @@ int main()
     test<const int*, bidirectional_iterator<const int*> >();
     test<const int*, random_access_iterator<const int*> >();
     test<const int*, const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.iota/iota.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.iota/iota.pass.cpp
index 3128674253d..2c1c08e8b54 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.iota/iota.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.iota/iota.pass.cpp
@@ -28,10 +28,12 @@ test()
         assert(ia[i] == ir[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test<forward_iterator<int*> >();
     test<bidirectional_iterator<int*> >();
     test<random_access_iterator<int*> >();
     test<int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool1.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool1.fail.cpp
index 70173d08be6..1c56a670731 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool1.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool1.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::gcd(false, 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool2.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool2.fail.cpp
index 106434d9726..9390e50f1e7 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool2.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool2.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::gcd(2, true);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool3.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool3.fail.cpp
index 138bdd6db85..2aceb285bfe 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool3.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool3.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::gcd<volatile bool, int>(false, 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool4.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool4.fail.cpp
index 8e8e7559320..234a4d7cefa 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool4.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.bool4.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::gcd<int, const bool>(2, true);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral1.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral1.fail.cpp
index 7bcf29d13c2..1aeb5249fff 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral1.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral1.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::gcd(2.0, 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral2.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral2.fail.cpp
index aceb0ff63a9..89079181b51 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral2.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.not_integral2.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::gcd(4, 6.0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
index 83a90b984c5..bba3780bdc8 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
@@ -91,7 +91,7 @@ constexpr bool do_test(int = 0)
     return accumulate;
 }
 
-int main()
+int main(int, char**)
 {
     auto non_cce = std::rand(); // a value that can't possibly be constexpr
 
@@ -141,4 +141,6 @@ int main()
     static_assert(std::is_same_v<decltype(res), std::int64_t>, "");
     assert(res == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool1.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool1.fail.cpp
index 43fc1f5bfa5..ab199d7a8e5 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool1.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool1.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::lcm(false, 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool2.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool2.fail.cpp
index b9e1128dc9b..68bfd1d2171 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool2.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool2.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::lcm(2, true);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool3.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool3.fail.cpp
index 763b65f99f6..4f4042267eb 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool3.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool3.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::lcm<volatile bool, int>(false, 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool4.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool4.fail.cpp
index dd7c43a41f7..2cdbcefdc2d 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool4.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.bool4.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::lcm<int, const bool>(2, true);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral1.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral1.fail.cpp
index 81f25887e5a..968034b0228 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral1.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral1.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::lcm(2.0, 4);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral2.fail.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral2.fail.cpp
index ef039ca7984..ed2813f6a34 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral2.fail.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.not_integral2.fail.cpp
@@ -18,7 +18,9 @@
 #include <numeric>
 
 
-int main()
+int main(int, char**)
 {
     std::lcm(4, 6.0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
index a42303776b2..8a056706134 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
@@ -90,7 +90,7 @@ constexpr bool do_test(int = 0)
     return accumulate;
 }
 
-int main()
+int main(int, char**)
 {
     auto non_cce = std::rand(); // a value that can't possibly be constexpr
 
@@ -141,4 +141,6 @@ int main()
     static_assert(std::is_same_v<decltype(res1), std::int64_t>, "");
     assert(res1 == 1324997410816LL);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum.pass.cpp b/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum.pass.cpp
index 90a74e22f5e..4ea410712ca 100644
--- a/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum.pass.cpp
@@ -35,7 +35,7 @@ test()
         assert(ib[i] == ir[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -66,4 +66,6 @@ int main()
     test<const int*, bidirectional_iterator<int*> >();
     test<const int*, random_access_iterator<int*> >();
     test<const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum_op.pass.cpp
index eadcd5a3a1e..ab51b5b5b24 100644
--- a/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/partial.sum/partial_sum_op.pass.cpp
@@ -37,7 +37,7 @@ test()
         assert(ib[i] == ir[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<const int*>, output_iterator<int*> >();
     test<input_iterator<const int*>, forward_iterator<int*> >();
@@ -68,4 +68,6 @@ int main()
     test<const int*, bidirectional_iterator<int*> >();
     test<const int*, random_access_iterator<int*> >();
     test<const int*, int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp b/libcxx/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp
index ebdaaac91e0..031a12d290b 100644
--- a/libcxx/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp
@@ -46,7 +46,7 @@ void test_return_type()
     static_assert( std::is_same_v<T, decltype(std::reduce(p, p))> );
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<char>();
     test_return_type<int>();
@@ -59,4 +59,6 @@ int main()
     test<bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*> >();
     test<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp b/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp
index 22b5a7239c4..19c6b7d5fc8 100644
--- a/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp
@@ -48,7 +48,7 @@ void test_return_type()
     static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}))> );
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<char, int>();
     test_return_type<int, int>();
@@ -63,4 +63,6 @@ int main()
     test<bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*> >();
     test<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp
index 7c26921716a..adcf9287968 100644
--- a/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp
@@ -48,7 +48,7 @@ void test_return_type()
     static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}, std::plus<>()))>, "" );
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<char, int>();
     test_return_type<int, int>();
@@ -70,4 +70,6 @@ int main()
     unsigned res = std::reduce(v.begin(), v.end(), 1U, std::multiplies<>());
     assert(res == 40320);       // 8! will not fit into a char
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp b/libcxx/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp
index dc9412ec1f5..528802cb4bf 100644
--- a/libcxx/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp
@@ -139,7 +139,7 @@ void basic_tests()
     }
 }
 
-int main()
+int main(int, char**)
 {
     basic_tests();
 
@@ -150,4 +150,6 @@ int main()
     test<random_access_iterator<const int*> >();
     test<const int*>();
     test<      int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop.pass.cpp b/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop.pass.cpp
index 412c4b2922c..f7a32131719 100644
--- a/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop.pass.cpp
@@ -113,7 +113,7 @@ void basic_tests()
     }
 }
 
-int main()
+int main(int, char**)
 {
     basic_tests();
 
@@ -124,4 +124,6 @@ int main()
     test<random_access_iterator<const int*> >();
     test<const int*>();
     test<      int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop_init.pass.cpp b/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop_init.pass.cpp
index d29131bd1a5..56e5bc6e75c 100644
--- a/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop_init.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop_init.pass.cpp
@@ -139,7 +139,7 @@ void basic_tests()
     }
 }
 
-int main()
+int main(int, char**)
 {
     basic_tests();
 
@@ -150,4 +150,6 @@ int main()
     test<random_access_iterator<const int*> >();
     test<const int*>();
     test<      int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp b/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp
index 541fbb76f9f..38071531b22 100644
--- a/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp
@@ -91,7 +91,7 @@ void test_move_only_types()
         [](const MoveOnly& target) { return MoveOnly{target.get() * 10}; }).get());
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<char, int>();
     test_return_type<int, int>();
@@ -117,4 +117,6 @@ int main()
     }
 
     test_move_only_types();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp b/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp
index 8f846a8930e..d74267c71fb 100644
--- a/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp
@@ -65,7 +65,7 @@ void test_move_only_types()
         std::transform_reduce(std::begin(ia), std::end(ia), std::begin(ib), MoveOnly{0}).get());
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<char, int>();
     test_return_type<int, int>();
@@ -103,4 +103,6 @@ int main()
     test<      int*,       unsigned int *>();
 
     test_move_only_types();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp b/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp
index 586e7b180db..27bad12ce61 100644
--- a/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp
@@ -69,7 +69,7 @@ void test_move_only_types()
         [](const MoveOnly& lhs, const MoveOnly& rhs) { return MoveOnly{lhs.get() * rhs.get()}; }).get());
 }
 
-int main()
+int main(int, char**)
 {
     test_return_type<char, int>();
     test_return_type<int, int>();
@@ -107,4 +107,6 @@ int main()
     test<      int*,       unsigned int *>();
 
     test_move_only_types();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numeric.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/numeric.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numeric.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/numerics.general/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/numerics.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/numerics.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/numerics.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/assign.pass.cpp
index dbc038fc5bc..5deb1d50cfa 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/assign.pass.cpp
@@ -48,8 +48,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/copy.pass.cpp
index 78bc6b2972a..443f4f8d86c 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/copy.pass.cpp
@@ -46,8 +46,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_copy.pass.cpp
index a0833fb4a72..57f2bcc76a3 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_copy.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::ranlux24_base Engine;
@@ -25,4 +25,6 @@ int main()
         Adaptor a(e);
         assert(a.base() == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_move.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_move.pass.cpp
index 5df116384d7..ade8e8d81cf 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_move.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_engine_move.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::ranlux24_base Engine;
@@ -26,4 +26,6 @@ int main()
         Adaptor a(std::move(e0));
         assert(a.base() == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_result_type.pass.cpp
index 4022917b9f0..6fe0947631c 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_result_type.pass.cpp
@@ -43,8 +43,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_sseq.pass.cpp
index c56bf4503ce..fe2d9fea312 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/ctor_sseq.pass.cpp
@@ -47,8 +47,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/default.pass.cpp
index 703dd3d7c9e..32af7046fdd 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/default.pass.cpp
@@ -34,8 +34,10 @@ test2()
     assert(e1() == 23459059301164ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/discard.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/discard.pass.cpp
index ca675b9ffba..a6f4d64e334 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/discard.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/discard.pass.cpp
@@ -44,8 +44,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/eval.pass.cpp
index 33e0f73ee86..75f07aecae5 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/eval.pass.cpp
@@ -34,8 +34,10 @@ test2()
     assert(e() == 276846226770426ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/io.pass.cpp
index ebfddfc371d..a9fbd7963e8 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/io.pass.cpp
@@ -55,8 +55,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/result_type.pass.cpp
index 7df00d8e629..a18e09bd15f 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/result_type.pass.cpp
@@ -34,8 +34,10 @@ test2()
         std::uint_fast64_t>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_result_type.pass.cpp
index 0dff0790c6a..bfa93767eaa 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_result_type.pass.cpp
@@ -42,8 +42,10 @@ test2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_sseq.pass.cpp
index 738b306b256..5506cffa117 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/seed_sseq.pass.cpp
@@ -40,8 +40,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/values.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/values.pass.cpp
index fef9ab49737..423a629e7f2 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/values.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.disc/values.pass.cpp
@@ -64,8 +64,10 @@ test2()
     where(E::used_block);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/assign.pass.cpp
index def8387e169..79205aacc73 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/assign.pass.cpp
@@ -48,8 +48,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/copy.pass.cpp
index 179ffaf46d1..22e68626ede 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/copy.pass.cpp
@@ -46,8 +46,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_copy.pass.cpp
index c858600ccb1..65fad3e2f83 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_copy.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::mt19937 Engine;
@@ -25,4 +25,6 @@ int main()
         Adaptor a(e);
         assert(a.base() == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_move.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_move.pass.cpp
index 1ecf36c43c5..f3b1d526fde 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_move.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_engine_move.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::mt19937 Engine;
@@ -26,4 +26,6 @@ int main()
         Adaptor a(std::move(e0));
         assert(a.base() == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_result_type.pass.cpp
index 9fa1383a841..84817b16ea4 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_result_type.pass.cpp
@@ -43,8 +43,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_sseq.pass.cpp
index a179753a88e..d2792f98f05 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/ctor_sseq.pass.cpp
@@ -47,8 +47,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/default.pass.cpp
index 422aaf936e3..d7e72e3e72a 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/default.pass.cpp
@@ -34,8 +34,10 @@ test2()
     assert(e1() == 18223106896348967647ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/discard.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/discard.pass.cpp
index fa735c09e72..8f292192361 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/discard.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/discard.pass.cpp
@@ -44,8 +44,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/eval.pass.cpp
index 036dc1fbc9a..9d60eaba39a 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/eval.pass.cpp
@@ -129,7 +129,7 @@ test8()
     assert(e() == 16470362623952407241ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -139,4 +139,6 @@ int main()
     test6();
     test7();
     test8();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/io.pass.cpp
index 0362cbfc23a..b1a73193c24 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/io.pass.cpp
@@ -55,8 +55,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/result_type.pass.cpp
index ee47a38b9e3..1b6fb87e347 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/result_type.pass.cpp
@@ -77,8 +77,10 @@ test2()
         unsigned long long>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_result_type.pass.cpp
index 204c89739c5..8225044d778 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_result_type.pass.cpp
@@ -42,8 +42,10 @@ test2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_sseq.pass.cpp
index 5c1c34e728d..04374d00098 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/seed_sseq.pass.cpp
@@ -40,8 +40,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/values.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/values.pass.cpp
index 10d9f4d7554..be25ad1e2b0 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/values.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.ibits/values.pass.cpp
@@ -51,8 +51,10 @@ test2()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/assign.pass.cpp
index d3518432c38..da08f58edb6 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/assign.pass.cpp
@@ -32,7 +32,9 @@ test1()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/copy.pass.cpp
index 7c4930879ae..5788371c36e 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/copy.pass.cpp
@@ -31,7 +31,9 @@ test1()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_copy.pass.cpp
index 4bd8052627c..0cc29d496dc 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_copy.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::minstd_rand0 Engine;
@@ -29,4 +29,6 @@ int main()
 
         assert(a.base() == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_move.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_move.pass.cpp
index 6daa356a7dc..35474e6a0d6 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_move.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_engine_move.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::minstd_rand0 Engine;
@@ -30,4 +30,6 @@ int main()
 
         assert(a.base() == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_result_type.pass.cpp
index ba0350fc5fb..5ca51e151e0 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_result_type.pass.cpp
@@ -69,7 +69,9 @@ test1()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_sseq.pass.cpp
index 3d3c06db2a2..136e7fe873f 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/ctor_sseq.pass.cpp
@@ -72,7 +72,9 @@ test1()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/default.pass.cpp
index 438c60790f0..fff5cee2d07 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/default.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(e1() == 152607844u);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/discard.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/discard.pass.cpp
index 3e98bf554d5..1b86048c2e2 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/discard.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/discard.pass.cpp
@@ -30,7 +30,9 @@ test1()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/eval.pass.cpp
index fa7056ca965..4eecfea81b7 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/eval.pass.cpp
@@ -86,9 +86,11 @@ test3()
     assert(e() == 500);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
     test3();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/io.pass.cpp
index 5d7a49a5f3b..5d80b3afcbc 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/io.pass.cpp
@@ -41,7 +41,9 @@ test1()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/result_type.pass.cpp
index 5ba0b5ed2f5..bcb08557c86 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/result_type.pass.cpp
@@ -77,8 +77,10 @@ test2()
         unsigned long long>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_result_type.pass.cpp
index 0d71f27e28a..24ccfbbf8e0 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_result_type.pass.cpp
@@ -29,7 +29,9 @@ test1()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_sseq.pass.cpp
index 0a5d386b1e5..8dfbcb00ee7 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/seed_sseq.pass.cpp
@@ -28,7 +28,9 @@ test1()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/values.pass.cpp b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/values.pass.cpp
index 8f9e52442a9..d98fdf58a82 100644
--- a/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/values.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/values.pass.cpp
@@ -44,7 +44,9 @@ test1()
     where(E::table_size);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.device/ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.device/ctor.pass.cpp
index c9838f68144..24e372795f0 100644
--- a/libcxx/test/std/numerics/rand/rand.device/ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.device/ctor.pass.cpp
@@ -62,7 +62,7 @@ void check_random_device_invalid(const std::string &token) {
 }
 
 
-int main() {
+int main(int, char**) {
   {
     std::random_device r;
   }
@@ -99,4 +99,6 @@ int main() {
     std::random_device r;
   }
 #endif // !defined(_WIN32)
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.device/entropy.pass.cpp b/libcxx/test/std/numerics/rand/rand.device/entropy.pass.cpp
index 38197137743..539c238ba3a 100644
--- a/libcxx/test/std/numerics/rand/rand.device/entropy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.device/entropy.pass.cpp
@@ -15,9 +15,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::random_device r;
     double e = r.entropy();
     ((void)e); // Prevent unused warning
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.device/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.device/eval.pass.cpp
index b5b8aa11fd5..4b68282f77c 100644
--- a/libcxx/test/std/numerics/rand/rand.device/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.device/eval.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::random_device r;
@@ -45,4 +45,6 @@ int main()
     {
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/assign.pass.cpp
index bbd200d21c9..5ed93470d03 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/assign.pass.cpp
@@ -26,7 +26,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/copy.pass.cpp
index bf4291cec18..e3d866ad461 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/copy.pass.cpp
@@ -24,7 +24,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_double.pass.cpp
index 1d9a22d1e7d..a8f76bb2324 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_double.pass.cpp
@@ -15,7 +15,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -32,4 +32,6 @@ int main()
         D d(0.75);
         assert(d.p() == 0.75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_param.pass.cpp
index 5543f407322..a568cb2b78a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/ctor_param.pass.cpp
@@ -15,7 +15,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -24,4 +24,6 @@ int main()
         D d(p);
         assert(d.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eq.pass.cpp
index faa683d4db8..24babc11829 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eq.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -32,4 +32,6 @@ int main()
         D d2(.25);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp
index a16d5247508..e28c39099f8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp
@@ -26,7 +26,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -100,4 +100,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval_param.pass.cpp
index 6d83410d83e..bf1d1174337 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval_param.pass.cpp
@@ -26,7 +26,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -104,4 +104,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/get_param.pass.cpp
index d24316d878c..0e960d6acba 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/get_param.pass.cpp
@@ -15,7 +15,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -24,4 +24,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/io.pass.cpp
index 5107e900604..7c7829796d8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/io.pass.cpp
@@ -24,7 +24,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -36,4 +36,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/max.pass.cpp
index acb1ada865b..6f4ac7e3d47 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/max.pass.cpp
@@ -15,11 +15,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
         D d(.25);
         assert(d.max() == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/min.pass.cpp
index 626f014b82c..8c369dbf828 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/min.pass.cpp
@@ -15,11 +15,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
         D d(.5);
         assert(d.min() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_assign.pass.cpp
index f8ea5be59d1..b4fcd04ecfc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_assign.pass.cpp
@@ -16,7 +16,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -26,4 +26,6 @@ int main()
         p = p0;
         assert(p.p() == .7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_copy.pass.cpp
index 91a8bacb7f8..96ddd4bc4a9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_copy.pass.cpp
@@ -16,7 +16,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -25,4 +25,6 @@ int main()
         param_type p = p0;
         assert(p.p() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_ctor.pass.cpp
index cf1b7d391af..612e6c6860c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_ctor.pass.cpp
@@ -16,7 +16,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -30,4 +30,6 @@ int main()
         param_type p(0.25);
         assert(p.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_eq.pass.cpp
index b41a8f7785a..cde5611ec37 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_eq.pass.cpp
@@ -16,7 +16,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -32,4 +32,6 @@ int main()
         param_type p2(0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_types.pass.cpp
index a8d6ba15fac..e1d9532f019 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/param_types.pass.cpp
@@ -15,7 +15,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -23,4 +23,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/set_param.pass.cpp
index 55af455973c..03e3d8a8c78 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/set_param.pass.cpp
@@ -15,7 +15,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
@@ -25,4 +25,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/types.pass.cpp
index 0be93b4b0d5..539b809b068 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/types.pass.cpp
@@ -15,11 +15,13 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::bernoulli_distribution D;
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, bool>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/assign.pass.cpp
index 746a35fb54a..e997198adb6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/copy.pass.cpp
index f6619293848..2c2b65c9441 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_int_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_int_double.pass.cpp
index f9ff59cd487..26a6e3a6622 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_int_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_int_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.t() == 3);
         assert(d.p() == 0.75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_param.pass.cpp
index 569ec41c39d..fa69b91237a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.t() == 5);
         assert(d.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eq.pass.cpp
index b6c8aeb4a24..dbe086ad4c7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -39,4 +39,6 @@ int main()
         D d2(4, .25);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval.pass.cpp
index 06f16c25777..fea71ccb876 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval.pass.cpp
@@ -506,7 +506,7 @@ test11()
 //    assert(kurtosis == x_kurtosis);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -519,4 +519,6 @@ int main()
     test9();
     test10();
     test11();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval_param.pass.cpp
index 78a9e6e3b04..cd4d0067878 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/eval_param.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -156,4 +156,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.04);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/get_param.pass.cpp
index 304a6b61a62..a3ba48f5583 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/io.pass.cpp
index 90eeb394c5d..cb272152a3b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/max.pass.cpp
index 946e7ed93c3..c8ca662b630 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/max.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
         D d(4, .25);
         assert(d.max() == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/min.pass.cpp
index c6ac01110b4..ce793f67b7f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
         D d(4, .5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_assign.pass.cpp
index 24250bbcea9..069d6e440b8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.t() == 6);
         assert(p.p() == .7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_copy.pass.cpp
index 9445502ed02..f2b78e6d8f4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.t() == 10);
         assert(p.p() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_ctor.pass.cpp
index 2a7f9284379..8ba09a681b2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.t() == 10);
         assert(p.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_eq.pass.cpp
index 0e705adcf6f..0ba4381ad18 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(3, 0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_types.pass.cpp
index 4e95286f37d..ba94d412a9f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/set_param.pass.cpp
index 66f1d875d50..ec82a93ffc0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/types.pass.cpp
index 60f81149906..c52681a1354 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bin/types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::binomial_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, long>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/assign.pass.cpp
index 99d7a6dc138..ae49feb3e3d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/copy.pass.cpp
index ea83185e598..73ff6d68f95 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_double.pass.cpp
index f099589c8a4..1d4388e4dc3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(0.75);
         assert(d.p() == 0.75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_param.pass.cpp
index f682fb71c74..3bcebc36f80 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eq.pass.cpp
index aa358fe74e1..47ea0f28247 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(.25);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval.pass.cpp
index 4addb5e153b..46ec8812193 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval.pass.cpp
@@ -286,7 +286,7 @@ test6()
     assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -294,4 +294,6 @@ int main()
     test4();
     test5();
     test6();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval_param.pass.cpp
index a3194c4d123..825fa3f5c4d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/eval_param.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -156,4 +156,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/get_param.pass.cpp
index 2ef2406200e..35679a8627e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/io.pass.cpp
index fb419b46849..36de49f78cf 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/max.pass.cpp
index 00a3780edc6..9e785da2eed 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/max.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
         D d(.25);
         assert(d.max() == std::numeric_limits<int>::max());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/min.pass.cpp
index ab9e964f0af..63f69f25e2a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
         D d(.5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_assign.pass.cpp
index 0b6033d395b..c88af2d68e1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         p = p0;
         assert(p.p() == .7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_copy.pass.cpp
index 92f9177673a..117b98bc129 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         param_type p = p0;
         assert(p.p() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_ctor.pass.cpp
index 75a9b436d54..71710228597 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         param_type p(0.25);
         assert(p.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_eq.pass.cpp
index 973491fd8ec..a741f06f603 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_types.pass.cpp
index bb80250a1b8..2f9efc268c9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/set_param.pass.cpp
index e66f9ace40f..74d49d5d8e2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/types.pass.cpp
index 528996f5041..a62b66134e7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.geo/types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::geometric_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, long>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/assign.pass.cpp
index 8b6d1e5a55f..20f7f9ffd10 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/copy.pass.cpp
index 68c7703b270..73ee12e430b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_int_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_int_double.pass.cpp
index 3b18e806890..0b9418b7c26 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_int_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_int_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.k() == 3);
         assert(d.p() == 0.75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_param.pass.cpp
index 51b875da968..485a3ae98f9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.k() == 5);
         assert(d.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eq.pass.cpp
index 7fa43ae9ad7..b93084e479f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -39,4 +39,6 @@ int main()
         D d2(4, .25);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval.pass.cpp
index 039403eea2f..4a8f7884246 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval.pass.cpp
@@ -284,7 +284,7 @@ test6()
     assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.03);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -292,4 +292,6 @@ int main()
     test4();
     test5();
     test6();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval_param.pass.cpp
index d1f6b62581a..b99f6fb07e5 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/eval_param.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -156,4 +156,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.03);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/get_param.pass.cpp
index 0cfe69f0ee4..63fe3804315 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/io.pass.cpp
index cb5ca473f54..a26f1990617 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/max.pass.cpp
index c5c1cc10676..3bc54a4be4d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/max.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
         D d(4, .25);
         assert(d.max() == std::numeric_limits<int>::max());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/min.pass.cpp
index 2dfa797ccc8..b2354d77c0e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
         D d(4, .5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_assign.pass.cpp
index d2e94877161..7968b01e843 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.k() == 6);
         assert(p.p() == .7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_copy.pass.cpp
index ded91956961..b16818b26a4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.k() == 10);
         assert(p.p() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_ctor.pass.cpp
index 0fc228a32d1..ad7908d314c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.k() == 10);
         assert(p.p() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_eq.pass.cpp
index d65fa544f7a..793b4361cd9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(3, 0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_types.pass.cpp
index 0ac9230ce02..c0164edc8fa 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/set_param.pass.cpp
index d785330a4e3..8971be5ee48 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/types.pass.cpp
index 6d2b75585b9..ea177377a88 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.negbin/types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::negative_binomial_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, long>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/assign.pass.cpp
index 66d5a7adeaa..dfe8785ff9f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/copy.pass.cpp
index 3d7db5423b4..85511d16107 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_double_double.pass.cpp
index eb4068c4b2e..f452b6e0bf3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.a() == 14.5);
         assert(d.b() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_param.pass.cpp
index aedfbb5d3b6..3a8ed3cc959 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.a() == 0.25);
         assert(d.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eq.pass.cpp
index e4e29635697..bc42b94f9ec 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval.pass.cpp
index f578164bdef..2b63645ae7d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval.pass.cpp
@@ -26,7 +26,7 @@ f(double x, double a, double b)
     return 1/3.1415926535897932 * std::atan((x - a)/b) + .5;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -73,4 +73,6 @@ int main()
         for (int i = 0; i < N; ++i)
             assert(std::abs(f(u[i], a, b) - double(i)/N) < .001);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval_param.pass.cpp
index 450e1922563..56921fe0fa7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/eval_param.pass.cpp
@@ -26,7 +26,7 @@ f(double x, double a, double b)
     return 1/3.1415926535897932 * std::atan((x - a)/b) + .5;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -79,4 +79,6 @@ int main()
         for (int i = 0; i < N; ++i)
             assert(std::abs(f(u[i], a, b) - double(i)/N) < .001);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/get_param.pass.cpp
index 635d116eb0e..c3c88b8d7e0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/io.pass.cpp
index 73a7e11aeb8..db50cfd5c93 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/max.pass.cpp
index bfde51747e8..963e8ed379b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/min.pass.cpp
index 2e2ba7db803..59044b8e272 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
         D d(.5, .5);
         assert(d.min() == -INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_assign.pass.cpp
index c2a7a04dcdb..04d94e74db5 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.a() == .75);
         assert(p.b() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_copy.pass.cpp
index 0ee42ef6418..88739df6827 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.a() == 10);
         assert(p.b() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_ctor.pass.cpp
index 3c44670683d..8563bafbb8c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.a() == 10);
         assert(p.b() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_eq.pass.cpp
index 12ce7de78a0..97553701ecf 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_types.pass.cpp
index 327d1e7d63b..ca0539c4140 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/set_param.pass.cpp
index 9b5b4af160b..ba66ec16ab6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/types.pass.cpp
index b88e6328ab2..09f79da5126 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.cauchy/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::cauchy_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/assign.pass.cpp
index cd25b1929b0..75242c2b943 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/copy.pass.cpp
index c7881c68603..3eeba40d01e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_double.pass.cpp
index 77279803e9f..a778b2face4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(14.5);
         assert(d.n() == 14.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_param.pass.cpp
index 7cf8c7dfb5a..922e44f6116 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.n() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eq.pass.cpp
index f26b78a7996..8b9ad457428 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval.pass.cpp
index 81f3359ebc5..b080886a8d1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -148,4 +148,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval_param.pass.cpp
index 09a33327f4d..86ac86ed350 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/eval_param.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -154,4 +154,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/get_param.pass.cpp
index 0173fb3f41e..55fda0872c6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/io.pass.cpp
index fde2fecf009..1017861318f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/max.pass.cpp
index d5b337f2c56..19ab87ca9e3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/min.pass.cpp
index 54d800559c6..af5b4561728 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
         D d(.5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_assign.pass.cpp
index fa243f22c34..0b13690f2b0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         p = p0;
         assert(p.n() == .75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_copy.pass.cpp
index c73f93a321f..22fe4b4ec30 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         param_type p = p0;
         assert(p.n() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_ctor.pass.cpp
index 34476f939f5..b3bbd8668a0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         param_type p(10);
         assert(p.n() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_eq.pass.cpp
index e40f5d19f8f..f615acad8c5 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_types.pass.cpp
index 4ecb983b242..a6727c429fa 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/set_param.pass.cpp
index eecfbf2feee..d497407e1e0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/types.pass.cpp
index d211af8bbc8..e33551debf2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.chisq/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::chi_squared_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/assign.pass.cpp
index c7eb0f983b1..c73d46ccb0f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/copy.pass.cpp
index 6ef45d0d55a..9a9670154b4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_double_double.pass.cpp
index 8b5acf39993..b29664ee486 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.m() == 14.5);
         assert(d.n() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_param.pass.cpp
index 2762c8dbb0f..3318d52229f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.m() == 0.25);
         assert(d.n() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eq.pass.cpp
index ea040c9c62c..b91da051158 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval.pass.cpp
index 55c8ccf1b0a..9a4cdf175d2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval.pass.cpp
@@ -45,7 +45,7 @@ f(double x, double m, double n)
     return I(m * x / (m*x + n), static_cast<unsigned>(m/2), static_cast<unsigned>(n/2));
 }
 
-int main()
+int main(int, char**)
 {
     // Purposefully only testing even integral values of m and n (for now)
     {
@@ -99,4 +99,6 @@ int main()
         for (int i = 0; i < N; ++i)
             assert(std::abs(f(u[i], d.m(), d.n()) - double(i)/N) < .01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval_param.pass.cpp
index 13818e02600..59a19d57ed2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/eval_param.pass.cpp
@@ -45,7 +45,7 @@ f(double x, double m, double n)
     return I(m * x / (m*x + n), static_cast<unsigned>(m/2), static_cast<unsigned>(n/2));
 }
 
-int main()
+int main(int, char**)
 {
     // Purposefully only testing even integral values of m and n (for now)
     {
@@ -105,4 +105,6 @@ int main()
         for (int i = 0; i < N; ++i)
             assert(std::abs(f(u[i], p.m(), p.n()) - double(i)/N) < .01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/get_param.pass.cpp
index 386696acec5..716d852dd10 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/io.pass.cpp
index c08d61e1d24..870d086ccd6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/max.pass.cpp
index 27bd09fc142..5e9c2968bd7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/min.pass.cpp
index a3e382c7f9a..8aca42d94e7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
         D d(.5, .5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_assign.pass.cpp
index d026525e732..3622aeb3933 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.m() == .75);
         assert(p.n() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_copy.pass.cpp
index 21364a393e5..cc936174c38 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.m() == 10);
         assert(p.n() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_ctor.pass.cpp
index 7adacd37b90..b7bef507d08 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.m() == 10);
         assert(p.n() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_eq.pass.cpp
index f4fb9bb9f65..1345723ec1b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_types.pass.cpp
index 3a716bf7c89..8fdb9fccfcc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/set_param.pass.cpp
index 9164f750fe0..cad5deda3ca 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/types.pass.cpp
index ee96f346066..567ed9f1273 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.f/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::fisher_f_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/assign.pass.cpp
index 20157a2eda0..567ae63b8a5 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/copy.pass.cpp
index 4e73c9d2209..f27ea836a99 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_double_double.pass.cpp
index d1116cca6e1..e19839f2a48 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.m() == 14.5);
         assert(d.s() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_param.pass.cpp
index f88d433059b..09ee798b8fd 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.m() == 0.25);
         assert(d.s() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eq.pass.cpp
index 627f5796120..7257f57b1dc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval.pass.cpp
index bcbc04c32fb..90841754881 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval.pass.cpp
@@ -248,11 +248,13 @@ test5()
     assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.7);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
     test3();
     test4();
     test5();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval_param.pass.cpp
index 350a3258763..1c40e66b224 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/eval_param.pass.cpp
@@ -258,11 +258,13 @@ test5()
     assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.7);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
     test3();
     test4();
     test5();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/get_param.pass.cpp
index a553901fe2f..e56cae65b36 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/io.pass.cpp
index 10ee0e82003..204a8f5f3b2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/max.pass.cpp
index 815db8a8935..2297a4160d3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/min.pass.cpp
index d199cc0b999..84154865b93 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
         D d(.5, .5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_assign.pass.cpp
index 3597e6d470f..9999b8499f0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.m() == .75);
         assert(p.s() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_copy.pass.cpp
index a0657ce5cca..6ad49592fb1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.m() == 10);
         assert(p.s() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_ctor.pass.cpp
index cd533afd877..cb1735b790f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.m() == 10);
         assert(p.s() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_eq.pass.cpp
index 8e4cd9a6ffa..a6be4db10ad 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_types.pass.cpp
index 7f2b726b147..99f13be070c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/set_param.pass.cpp
index bc67664b0e5..9924757177d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/types.pass.cpp
index ae8b59b6615..6bff26088a0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.lognormal/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::lognormal_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/assign.pass.cpp
index 77c3cfbe2da..492a0ea6aef 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/copy.pass.cpp
index fa130e4c9a8..f2326bbc343 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_double_double.pass.cpp
index 5081372829b..2c4462f252a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.mean() == 14.5);
         assert(d.stddev() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_param.pass.cpp
index bdb5c69f658..66331187c52 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.mean() == 0.25);
         assert(d.stddev() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eq.pass.cpp
index ff62af28048..87b7c4d7d0d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval.pass.cpp
index b2cf8534d92..5362aef09f8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -66,4 +66,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs(kurtosis - x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval_param.pass.cpp
index 55f0c8180e6..343bdd7dc6f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/eval_param.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -68,4 +68,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs(kurtosis - x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/get_param.pass.cpp
index f173955013f..a293371069b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/io.pass.cpp
index 765c4518789..601f8d58014 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/max.pass.cpp
index 9218cfa8359..24adfc05c7c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/min.pass.cpp
index 1ec45642527..0e2c27a183e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
         D d(.5, .5);
         assert(d.min() == -INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_assign.pass.cpp
index 08195232eba..4a37869230b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.mean() == .75);
         assert(p.stddev() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_copy.pass.cpp
index cc16ec7e3c1..7ae72e6dfd2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.mean() == 10);
         assert(p.stddev() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_ctor.pass.cpp
index f58fd3b5aea..e947060e520 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.mean() == 10);
         assert(p.stddev() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_eq.pass.cpp
index 859dba8a4a6..cf7fa39cf31 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_types.pass.cpp
index ef88be7996e..2fef65e8c29 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/set_param.pass.cpp
index 7b4e9ca4b1c..46f1cb2ee05 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/types.pass.cpp
index 754e2c28dd2..f532786c9d8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.normal/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::normal_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/assign.pass.cpp
index e2566347ea3..bb6ced5e887 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/copy.pass.cpp
index 0f64eb7cc62..a6aa61180fa 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_double.pass.cpp
index 88827fee4d3..a133ff30c62 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(14.5);
         assert(d.n() == 14.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_param.pass.cpp
index ba286242ce3..be11e9224c1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.n() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eq.pass.cpp
index e513658138a..2de6ca5513b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval.pass.cpp
index d8b3783e9e3..bb1630ea44d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -135,4 +135,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval_param.pass.cpp
index cb47b07a6d0..3b939010a99 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/eval_param.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -141,4 +141,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/get_param.pass.cpp
index f1cd34de749..170aed3dbec 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/io.pass.cpp
index 8fb8381daf9..60f9a6fb3ff 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/max.pass.cpp
index f64207c4063..f2fe365443b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/min.pass.cpp
index 8f6d4f65b0c..ab98be4504f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
         D d(.5);
         assert(d.min() == -INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_assign.pass.cpp
index 25137f9c136..54e9313ae67 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         p = p0;
         assert(p.n() == .75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_copy.pass.cpp
index b207d7dec3b..a27a735ca41 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         param_type p = p0;
         assert(p.n() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_ctor.pass.cpp
index bcaac8774e2..897a3e3cff4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         param_type p(10);
         assert(p.n() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_eq.pass.cpp
index eea4cc99bd8..cd3a04a341e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_types.pass.cpp
index b064d111ce3..1acecc1d110 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/set_param.pass.cpp
index 2b451681114..85c6a3cb1cd 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/types.pass.cpp
index c9fc1aaccda..f89da9f9ede 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.norm/rand.dist.norm.t/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::student_t_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/assign.pass.cpp
index 8ce712a5469..bfee1f279ad 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/copy.pass.cpp
index df5b00fb8bc..41119b4fefc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_double.pass.cpp
index 479f221e037..530d7de9a93 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(3.5);
         assert(d.lambda() == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_param.pass.cpp
index 31926e520ed..174e91f8f31 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.lambda() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eq.pass.cpp
index 27841184cc1..609f226a540 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(.25);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval.pass.cpp
index db71f9c905b..bfe7e8da385 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -148,4 +148,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval_param.pass.cpp
index 28f6e6d78ac..00054a76e68 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/eval_param.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -72,4 +72,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/get_param.pass.cpp
index c33383261f1..9cb46bf04f6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/io.pass.cpp
index d8b4da1f37b..e8613480c6e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/max.pass.cpp
index bf02b03bddf..9859883c125 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == std::numeric_limits<D::result_type>::infinity());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/min.pass.cpp
index abca78185c6..e1957295213 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
         D d(.5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_assign.pass.cpp
index 47ca9d508a2..9958d632b2a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         p = p0;
         assert(p.lambda() == .7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_copy.pass.cpp
index df00ddd2286..676eac6465b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         param_type p = p0;
         assert(p.lambda() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_ctor.pass.cpp
index 9eb9881f5e7..8483bf9ff75 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         param_type p(10);
         assert(p.lambda() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_eq.pass.cpp
index 085f55639de..e36ffe029f7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_types.pass.cpp
index 9e43dff4a99..1b137acf9a9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/set_param.pass.cpp
index bc36185782a..7147b313c79 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/types.pass.cpp
index fe9f84be0db..289c2f1a4a1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.exp/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::exponential_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/assign.pass.cpp
index 8aab78c0798..15333b04804 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/copy.pass.cpp
index 48f8b46b792..a71dd8e31a4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_double_double.pass.cpp
index 2b02acf62d9..1123da3f226 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.a() == 14.5);
         assert(d.b() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_param.pass.cpp
index 3e569438a00..4160b0337e3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.a() == 0.25);
         assert(d.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eq.pass.cpp
index 8d5e08f5ce0..ab14c2ac5c4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval.pass.cpp
index 42ccae9c85e..c83e78e01f6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval.pass.cpp
@@ -192,10 +192,12 @@ test4()
     assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
     test3();
     test4();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval_param.pass.cpp
index ef1ca6aafe5..bf3df445559 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/eval_param.pass.cpp
@@ -200,10 +200,12 @@ test4()
     assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
     test3();
     test4();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/get_param.pass.cpp
index fe300d6920c..27499a49a5f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/io.pass.cpp
index 9fefd6058b4..219d0f1e2da 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/max.pass.cpp
index b16f7f2a5c1..bfa6f248356 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/min.pass.cpp
index 199c14e5f75..bd97a0ba396 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
         D d(.5, .5);
         assert(d.min() == -INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_assign.pass.cpp
index cd2aac8cafd..b92b6fbe933 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.a() == .75);
         assert(p.b() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_copy.pass.cpp
index 58ad1f2c972..f64a3203050 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.a() == 10);
         assert(p.b() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_ctor.pass.cpp
index 3dd5e788e89..906f7160afc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.a() == 10);
         assert(p.b() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_eq.pass.cpp
index 532452c2e77..c4e4a7060ea 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_types.pass.cpp
index af00f4b7ff0..30c46459bb6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/set_param.pass.cpp
index f7ff8fdf473..88fff04fb10 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/types.pass.cpp
index 53ad76218b3..e96c0d4ad45 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.extreme/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::extreme_value_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/assign.pass.cpp
index 707c5b4b1da..35eb5c277cb 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/copy.pass.cpp
index b080f76a8a8..962374efe87 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_double_double.pass.cpp
index c359c08db15..31ce06d15aa 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.alpha() == 14.5);
         assert(d.beta() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_param.pass.cpp
index a475a67f5a4..c78821f871d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.alpha() == 0.25);
         assert(d.beta() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eq.pass.cpp
index 932c57a06f9..ee365f8e7c2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval.pass.cpp
index b972c3f5e8b..f9e678d1caa 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -147,4 +147,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval_param.pass.cpp
index 803daa82e3e..aeb0bbf31e0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/eval_param.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -153,4 +153,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/get_param.pass.cpp
index 31bbbfca87a..82b1c9bfd78 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/io.pass.cpp
index 6824616bdfc..6732ca210ff 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/max.pass.cpp
index 29df499678d..eb9e2b4f2e0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/min.pass.cpp
index 37eba2f10cf..3eda5a65183 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
         D d(.5, .5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_assign.pass.cpp
index 4470505003e..28d3997c4d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.alpha() == .75);
         assert(p.beta() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_copy.pass.cpp
index d7eb86d23a4..dc2b32dd7ee 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.alpha() == 10);
         assert(p.beta() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_ctor.pass.cpp
index 3c72bee5aae..333b670f1da 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.alpha() == 10);
         assert(p.beta() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_eq.pass.cpp
index d8cbeb23af1..2ba854163de 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_types.pass.cpp
index f9467d6a1a8..0fc07ef9584 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/set_param.pass.cpp
index ca1c4b48d7d..4af868a270b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/types.pass.cpp
index 197a9b224d5..31a33c0cf8a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.gamma/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::gamma_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/assign.pass.cpp
index ee487a41668..4379d0bfd05 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/copy.pass.cpp
index 2e141ca9295..60fa5193360 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_double.pass.cpp
index d5f86cb03f9..e27d13331d2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(3.5);
         assert(d.mean() == 3.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_param.pass.cpp
index c8ee8414682..117adb25a50 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.mean() == 0.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eq.pass.cpp
index cc7a8bd9d64..0d7dda0d972 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(.25);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval.pass.cpp
index 0e3d1c2e4d0..588eddba2eb 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -147,4 +147,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval_param.pass.cpp
index 27b6a9c39c4..67f72684313 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/eval_param.pass.cpp
@@ -28,7 +28,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -153,4 +153,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/get_param.pass.cpp
index 8d2b76df24c..a55a3837c7f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/io.pass.cpp
index e8ffce1faf4..4aec884f6b9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/max.pass.cpp
index 853d70749a3..b1cb125084a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == std::numeric_limits<int>::max());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/min.pass.cpp
index da95d9c4cef..e65319c56c2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
         D d(.5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_assign.pass.cpp
index 1982ff5dedc..393153a7c06 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         p = p0;
         assert(p.mean() == .7);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_copy.pass.cpp
index 841c7ddacae..a02e7250fc7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         param_type p = p0;
         assert(p.mean() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_ctor.pass.cpp
index 8dea424b488..1e395fdfd22 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         param_type p(10);
         assert(p.mean() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_eq.pass.cpp
index 307a0d08df1..5e9aa27ccf4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_types.pass.cpp
index c4e1e434a9d..b81d15cf0be 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/set_param.pass.cpp
index 406b8472284..d75e6a1daf8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/types.pass.cpp
index 16165b0b768..982919268be 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.poisson/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::poisson_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, unsigned long long>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/assign.pass.cpp
index c6090b523d9..ff81b812083 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/copy.pass.cpp
index 22d51fc3428..0cfafa7257a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_double_double.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_double_double.pass.cpp
index ac093c5f501..3f4d55eb9bd 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_double_double.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_double_double.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -36,4 +36,6 @@ int main()
         assert(d.a() == 14.5);
         assert(d.b() == 5.25);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_param.pass.cpp
index 4faae698b5e..e876a2df0e6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.a() == 0.25);
         assert(d.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eq.pass.cpp
index 12a3e2354d8..1de323aef10 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(2.5, 4.5);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval.pass.cpp
index 6d086b87d9a..88e40b29c54 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -160,4 +160,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.03);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval_param.pass.cpp
index 6142f847d37..3959f440797 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/eval_param.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -166,4 +166,6 @@ int main()
         assert(std::abs((skew - x_skew) / x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.03);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/get_param.pass.cpp
index fcc21fb2910..c2fbf7b98b9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/io.pass.cpp
index 7ecc16f5735..6b4f4e9ddbb 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/max.pass.cpp
index 30b504a9643..3d9fe0b357a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D::result_type m = d.max();
         assert(m == INFINITY);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/min.pass.cpp
index 16a89bcd43c..f92384041ac 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
         D d(.5, .5);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_assign.pass.cpp
index 3be04f26891..add72f68563 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.a() == .75);
         assert(p.b() == 6);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_copy.pass.cpp
index 800d6302a86..f2b7e95a4c3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.a() == 10);
         assert(p.b() == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_ctor.pass.cpp
index f88ba354563..6a03330c156 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.a() == 10);
         assert(p.b() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_eq.pass.cpp
index 621eda13f54..e47f576728c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(0.5, .5);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_types.pass.cpp
index cd7d5209f50..08c58d03d1a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/set_param.pass.cpp
index 05acfd5e650..f3c5a20d29e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/types.pass.cpp
index bd9b474794f..51b97e081d7 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.pois/rand.dist.pois.weibull/types.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::weibull_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/assign.pass.cpp
index a6d6822b6f8..f1d5b3b24c2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/assign.pass.cpp
@@ -28,7 +28,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/copy.pass.cpp
index 0b1b7b919c3..19f8dc179e2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/copy.pass.cpp
@@ -26,7 +26,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_default.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_default.pass.cpp
index 89fc479f2ba..f8d769dbda0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_default.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         assert(p.size() == 1);
         assert(p[0] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_func.pass.cpp
index 700eb91bae7..198b845b3e6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_func.pass.cpp
@@ -23,7 +23,7 @@ double fw(double x)
     return x+1;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -56,4 +56,6 @@ int main()
         assert(p[1] == .21875);
         assert(p[2] == .28125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_init.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_init.pass.cpp
index 51e43f4d2fe..a9c1e2bb42c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_init.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_init.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -77,4 +77,6 @@ int main()
         assert(p[1] == 0);
         assert(p[2] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_iterator.pass.cpp
index eafbd1b564d..66912cf4a94 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_iterator.pass.cpp
@@ -17,7 +17,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -83,4 +83,6 @@ int main()
         assert(p[1] == 0);
         assert(p[2] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_param.pass.cpp
index 8a18ab83e27..a25c9fbd31c 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -29,4 +29,6 @@ int main()
         assert(p[0] == 0.25);
         assert(p[1] == 0.75);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eq.pass.cpp
index 302e171ca08..409cc39ebb1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -41,4 +41,6 @@ int main()
         D d2;
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval.pass.cpp
index 170fc16a7f6..5dd70d144fa 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval.pass.cpp
@@ -19,7 +19,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -275,4 +275,6 @@ int main()
             else
                 assert(u[i] == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval_param.pass.cpp
index dbfd5da94bb..6cc4e90b25e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/eval_param.pass.cpp
@@ -19,7 +19,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -41,4 +41,6 @@ int main()
         for (int i = 0; i <= 2; ++i)
             assert(std::abs((double)u[i]/N - prob[i]) / prob[i] < 0.001);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/get_param.pass.cpp
index 26ef68c66de..59e33128243 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/io.pass.cpp
index 4e95cc47714..ff9434c8a16 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -38,4 +38,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/max.pass.cpp
index c6356cf7697..d365763914f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         D d(p0, p0+4);
         assert(d.max() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/min.pass.cpp
index b40c4c51336..259eddc5d02 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/min.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         D d(p0, p0+3);
         assert(d.min() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_assign.pass.cpp
index 23decd2b831..c50a2536c20 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         p = p0;
         assert(p == p0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_copy.pass.cpp
index a50a5f4244d..9b7e6b9edcf 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         param_type p = p0;
         assert(p == p0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_default.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_default.pass.cpp
index b915e2cb58b..680ce405c7e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_default.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.size() == 1);
         assert(p[0] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_func.pass.cpp
index 8d00e628334..4dd919dc4ec 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_func.pass.cpp
@@ -23,7 +23,7 @@ double fw(double x)
     return x+1;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -60,4 +60,6 @@ int main()
         assert(p[1] == .21875);
         assert(p[2] == .28125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_init.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_init.pass.cpp
index 69ffe3d4612..91adbdb07da 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_init.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_init.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -84,4 +84,6 @@ int main()
         assert(p[1] == 0);
         assert(p[2] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_iterator.pass.cpp
index aa7d6bfb820..b553ffab127 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_ctor_iterator.pass.cpp
@@ -17,7 +17,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -90,4 +90,6 @@ int main()
         assert(p[1] == 0);
         assert(p[2] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_eq.pass.cpp
index aac1d00fed8..3ca6786933f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -35,4 +35,6 @@ int main()
         param_type p2;
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_types.pass.cpp
index 558f8ad7f71..fab19160264 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/set_param.pass.cpp
index 9334f724563..9858a30a778 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -27,4 +27,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/types.pass.cpp
index 99a474a4cf8..d45475ba36f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.discrete/types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::discrete_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, long>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/assign.pass.cpp
index 1de6fd363ec..3b63601aee9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/assign.pass.cpp
@@ -29,7 +29,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/copy.pass.cpp
index 6d8e36ef3dc..82b0d8ef3f9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/copy.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_default.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_default.pass.cpp
index f05cd9941f7..836b690082a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_default.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         assert(dn.size() == 1);
         assert(dn[0] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_func.pass.cpp
index 7c8ae7fa88a..7e7537ad804 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_func.pass.cpp
@@ -23,7 +23,7 @@ double fw(double x)
     return 2*x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -60,4 +60,6 @@ int main()
         assert(dn[0] == 0.1);
         assert(dn[1] == 0.15);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_init_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_init_func.pass.cpp
index f86cbf56c4c..22c8a1f4ef2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_init_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_init_func.pass.cpp
@@ -26,7 +26,7 @@ double f(double x)
     return x*2;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -74,4 +74,6 @@ int main()
         assert(dn[0] == 0.203125);
         assert(dn[1] == 0.1484375);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_iterator.pass.cpp
index 463e78c850a..695a7ba5f16 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_iterator.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -92,4 +92,6 @@ int main()
         assert(dn[1] == .3125);
         assert(dn[2] == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_param.pass.cpp
index e9439d2933d..1a10bb31b36 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         assert(dn[1] == .3125);
         assert(dn[2] == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eq.pass.cpp
index 7cd8b1e069e..18b5d59bd10 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -43,4 +43,6 @@ int main()
         D d2;
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval.pass.cpp
index 048fb2d2221..d00be22e551 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval.pass.cpp
@@ -723,7 +723,7 @@ test11()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -736,4 +736,6 @@ int main()
     test9();
     test10();
     test11();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval_param.pass.cpp
index 0d0e6e50d8a..c82a6b8515a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/eval_param.pass.cpp
@@ -31,7 +31,7 @@ sqr(T x)
     return x*x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -95,4 +95,6 @@ int main()
             }
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/get_param.pass.cpp
index b842d2433f8..90f469480d9 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(pa);
         assert(d.param() == pa);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/io.pass.cpp
index e4748c15e5c..b22fdfa5840 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/max.pass.cpp
index 7de0052dfb7..19c11c66f22 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         D d(b, b+Np+1, p);
         assert(d.max() == 17);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/min.pass.cpp
index 601eeecc4ca..8a5fe519fb6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/min.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         D d(b, b+Np+1, p);
         assert(d.min() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_assign.pass.cpp
index 87d78547a55..7c42c738c14 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         p1 = p0;
         assert(p1 == p0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_copy.pass.cpp
index b9a22a15340..f9eec8d731f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -29,4 +29,6 @@ int main()
         P p1 = p0;
         assert(p1 == p0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_default.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_default.pass.cpp
index 4b3dad0af47..ac2f724b08e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_default.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         assert(dn.size() == 1);
         assert(dn[0] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_func.pass.cpp
index a8adb5be1c0..d14a50817c6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_func.pass.cpp
@@ -23,7 +23,7 @@ double fw(double x)
     return 2*x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -63,4 +63,6 @@ int main()
         assert(dn[0] == 0.1);
         assert(dn[1] == 0.15);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_init_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_init_func.pass.cpp
index 20a2cdbdcb2..b7e5a49639e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_init_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_init_func.pass.cpp
@@ -23,7 +23,7 @@ double f(double x)
     return x*2;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -75,4 +75,6 @@ int main()
         assert(dn[0] == 0.203125);
         assert(dn[1] == 0.1484375);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_iterator.pass.cpp
index 2b11672e263..96dda54d246 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_ctor_iterator.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -96,4 +96,6 @@ int main()
         assert(dn[1] == .3125);
         assert(dn[2] == .125);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_eq.pass.cpp
index c3fe7c42b87..4571613f987 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         P p2(b, b+4, p);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_types.pass.cpp
index 99132cdd8ed..3d4c25e882a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/set_param.pass.cpp
index b87bd85bc2c..a34187cb2ce 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         d.param(pa);
         assert(d.param() == pa);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/types.pass.cpp
index bfc3cb77499..eec866112d8 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.pconst/types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_constant_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/assign.pass.cpp
index d150c8668ed..ff478a05b79 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/assign.pass.cpp
@@ -29,7 +29,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/copy.pass.cpp
index bb87e31136e..ba5e6d59a17 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/copy.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_default.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_default.pass.cpp
index f96a044a488..ded81c974fc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_default.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -32,4 +32,6 @@ int main()
         assert(dn[0] == 1);
         assert(dn[1] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_func.pass.cpp
index fd42c225647..175774dc006 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_func.pass.cpp
@@ -25,7 +25,7 @@ double fw(double x)
     return 2*x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -65,4 +65,6 @@ int main()
         assert(dn[1] == 0.125);
         assert(dn[2] == 0.175);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_init_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_init_func.pass.cpp
index e4db52bc952..ab29fecf615 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_init_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_init_func.pass.cpp
@@ -26,7 +26,7 @@ double f(double x)
     return x*2;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -78,4 +78,6 @@ int main()
         assert(dn[1] == 0.125);
         assert(dn[2] == 0.175);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_iterator.pass.cpp
index 13517e1cc9f..541976ad1d5 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_iterator.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -97,4 +97,6 @@ int main()
         assert(dn[2] == 1/4.5);
         assert(dn[3] == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_param.pass.cpp
index 2592763cfa6..1ecbe87c20d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -38,4 +38,6 @@ int main()
         assert(dn[2] == 12.5/256.25);
         assert(dn[3] == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eq.pass.cpp
index 019335ee72e..19eda7357b2 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -43,4 +43,6 @@ int main()
         D d2;
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval.pass.cpp
index 1aab615ad0e..6476f3567ff 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval.pass.cpp
@@ -354,7 +354,7 @@ test6()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
@@ -362,4 +362,6 @@ int main()
     test4();
     test5();
     test6();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval_param.pass.cpp
index 11f2c492685..621320ca49e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/eval_param.pass.cpp
@@ -37,7 +37,7 @@ f(double x, double a, double m, double b, double c)
     return a + m*(sqr(x) - sqr(b))/2 + c*(x-b);
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -90,4 +90,6 @@ int main()
             assert(std::abs(f(u[i], a, m, bk, c) - double(i)/N) < .001);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/get_param.pass.cpp
index 56e648f50f7..7776330c049 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         D d(pa);
         assert(d.param() == pa);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/io.pass.cpp
index 845b64a9f37..258fdb77b83 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -40,4 +40,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/max.pass.cpp
index aa46f40b019..ea6530eae00 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/max.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         D d(b, b+Np, p);
         assert(d.max() == 17);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/min.pass.cpp
index 28a1b68f208..80c77d6e327 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/min.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         D d(b, b+Np, p);
         assert(d.min() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_assign.pass.cpp
index 3534a8935a1..145e616306d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -30,4 +30,6 @@ int main()
         p1 = p0;
         assert(p1 == p0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_copy.pass.cpp
index 8d784c66969..b409f58f08e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -29,4 +29,6 @@ int main()
         P p1 = p0;
         assert(p1 == p0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_default.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_default.pass.cpp
index 5d543cf5973..69d4d71f4e4 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_default.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -31,4 +31,6 @@ int main()
         assert(dn[0] == 1);
         assert(dn[1] == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_func.pass.cpp
index 48e34c743c0..c6ea33b1f15 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_func.pass.cpp
@@ -23,7 +23,7 @@ double fw(double x)
     return 2*x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -66,4 +66,6 @@ int main()
         assert(dn[1] == 0.125);
         assert(dn[2] == 0.175);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_init_func.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_init_func.pass.cpp
index cff26c592b8..3972715d0af 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_init_func.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_init_func.pass.cpp
@@ -23,7 +23,7 @@ double f(double x)
     return x*2;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -79,4 +79,6 @@ int main()
         assert(dn[1] == 0.125);
         assert(dn[2] == 0.175);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_iterator.pass.cpp
index 61122d6f625..4a51902a00f 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_ctor_iterator.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -101,4 +101,6 @@ int main()
         assert(dn[2] == 1/4.5);
         assert(dn[3] == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_eq.pass.cpp
index aab37f7bacb..e7a15d68305 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         P p2(b, b+4, p);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_types.pass.cpp
index 0907745d874..f6d65ddcc8e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/set_param.pass.cpp
index ff96a86573b..c5697d7ce64 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         d.param(pa);
         assert(d.param() == pa);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/types.pass.cpp
index d53117395c4..9d8bdf6fca1 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.samp/rand.dist.samp.plinear/types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::piecewise_linear_distribution<> D;
@@ -28,4 +28,6 @@ int main()
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/assign.pass.cpp
index 9c4d970b2a6..e34abf08899 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/copy.pass.cpp
index 8ddf2f0b370..796aebacc7d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_int_int.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_int_int.pass.cpp
index edbc060d038..8a4fd33589b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_int_int.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_int_int.pass.cpp
@@ -17,7 +17,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         assert(d.a() == -6);
         assert(d.b() == 106);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_param.pass.cpp
index c462f279cb0..2546810ec57 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.a() == 3);
         assert(d.b() == 8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eq.pass.cpp
index d1614923eb8..47e1c89532d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(3, 9);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval.pass.cpp
index 9056a983b22..a4e769bd77e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -452,4 +452,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval_param.pass.cpp
index 3d4524ca18f..77257a8656a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/eval_param.pass.cpp
@@ -27,7 +27,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -72,4 +72,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/get_param.pass.cpp
index 199d9a5b24a..62d144fe595 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/io.pass.cpp
index 2205a3f479c..3e029696508 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/max.pass.cpp
index cd196ee15fa..58ac8571f5b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/max.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
         D d(3, 8);
         assert(d.max() == 8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/min.pass.cpp
index d1b79a7ff6d..18b9b504572 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
         D d(3, 8);
         assert(d.min() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_assign.pass.cpp
index eeb8e635cbf..33d677a9131 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<long> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.a() == 5);
         assert(p.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_copy.pass.cpp
index 33f49ede485..1eae36b9632 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<long> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.a() == 5);
         assert(p.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_ctor.pass.cpp
index da9c08ae8f8..6fbf499ca5e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<long> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.a() == 5);
         assert(p.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_eq.pass.cpp
index 7f76fcc0a8d..b58a965676a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<long> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(6, 10);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_types.pass.cpp
index 84af7f98d55..b4844a64b01 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<long> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/set_param.pass.cpp
index a67791f3fb6..59b7b0728b5 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/types.pass.cpp
index 5cd31e5f668..60ff1cb3303 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.int/types.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_int_distribution<long> D;
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, long>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/assign.pass.cpp
index ebdfd0292e4..e348c04ed60 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/assign.pass.cpp
@@ -27,7 +27,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/copy.pass.cpp
index d53952ccf72..4fcc9efc3e6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/copy.pass.cpp
@@ -25,7 +25,9 @@ test1()
     assert(d1 == d2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_int_int.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_int_int.pass.cpp
index 8cb0a1f4318..c252c5bbbe3 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_int_int.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_int_int.pass.cpp
@@ -17,7 +17,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         assert(d.a() == -6);
         assert(d.b() == 106);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_param.pass.cpp
index b2913b7722c..20df543ea3d 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/ctor_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         assert(d.a() == 3.5);
         assert(d.b() == 8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eq.pass.cpp
index ef0eecafdb3..fb318626d55 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eq.pass.cpp
@@ -19,7 +19,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -33,4 +33,6 @@ int main()
         D d2(3, 8.1);
         assert(d1 != d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval.pass.cpp
index aaffa8035db..99fe1f825ec 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval.pass.cpp
@@ -29,7 +29,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -471,4 +471,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval_param.pass.cpp
index 79763903b2f..495f0e9c34a 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/eval_param.pass.cpp
@@ -27,7 +27,7 @@ sqr(T x)
     return x * x;
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -71,4 +71,6 @@ int main()
         assert(std::abs(skew - x_skew) < 0.01);
         assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/get_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/get_param.pass.cpp
index 58918c24f22..b6037554525 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/get_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/get_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -25,4 +25,6 @@ int main()
         D d(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/io.pass.cpp
index afea0a72037..1f6eb580657 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/io.pass.cpp
@@ -25,7 +25,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -37,4 +37,6 @@ int main()
         is >> d2;
         assert(d1 == d2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/max.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/max.pass.cpp
index ecda47ac3c0..ea75181f80e 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/max.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/max.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
         D d(3, 8);
         assert(d.max() == 8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/min.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/min.pass.cpp
index 77545c8f2e4..46455e8b416 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/min.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/min.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
         D d(3, 8);
         assert(d.min() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_assign.pass.cpp
index 1575b7feb52..ab4d5969377 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<float> D;
@@ -28,4 +28,6 @@ int main()
         assert(p.a() == 5);
         assert(p.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_copy.pass.cpp
index 9510b2bd518..24260405cfc 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_copy.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<float> D;
@@ -27,4 +27,6 @@ int main()
         assert(p.a() == 5);
         assert(p.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_ctor.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_ctor.pass.cpp
index 67dc714e49a..15cad423ef0 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_ctor.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<float> D;
@@ -40,4 +40,6 @@ int main()
         assert(p.a() == 5);
         assert(p.b() == 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_eq.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_eq.pass.cpp
index e9ee0056420..2127aebf482 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_eq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_eq.pass.cpp
@@ -17,7 +17,7 @@
 #include <limits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<float> D;
@@ -33,4 +33,6 @@ int main()
         param_type p2(6, 10);
         assert(p1 != p2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_types.pass.cpp
index 5c5ad233154..d2677580e34 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/param_types.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<float> D;
@@ -24,4 +24,6 @@ int main()
         typedef param_type::distribution_type distribution_type;
         static_assert((std::is_same<D, distribution_type>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/set_param.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/set_param.pass.cpp
index 021404ba40e..f651d72d1b6 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/set_param.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/set_param.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<> D;
@@ -26,4 +26,6 @@ int main()
         d.param(p);
         assert(d.param() == p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/types.pass.cpp
index 5b75a06570b..431b7374a0b 100644
--- a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.uni/rand.dist.uni.real/types.pass.cpp
@@ -16,11 +16,13 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::uniform_real_distribution<float> D;
         typedef D::result_type result_type;
         static_assert((std::is_same<result_type, float>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/assign.pass.cpp
index 313f4278d79..cfaad1a33a5 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/assign.pass.cpp
@@ -48,10 +48,12 @@ test()
     test1<T, M-1, M-1, M>();
 }
 
-int main()
+int main(int, char**)
 {
     test<unsigned short>();
     test<unsigned int>();
     test<unsigned long>();
     test<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/copy.pass.cpp
index c49d361787a..35585423442 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/copy.pass.cpp
@@ -48,10 +48,12 @@ test()
     test1<T, M-1, M-1, M>();
 }
 
-int main()
+int main(int, char**)
 {
     test<unsigned short>();
     test<unsigned int>();
     test<unsigned long>();
     test<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_result_type.pass.cpp
index 97d2ef2d290..4f2da2f612a 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_result_type.pass.cpp
@@ -129,7 +129,7 @@ test4()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1<unsigned short>();
     test1<unsigned int>();
@@ -150,4 +150,6 @@ int main()
     test4<unsigned int>();
     test4<unsigned long>();
     test4<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_sseq.pass.cpp
index a489bcd18da..7e82f6395f9 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/ctor_sseq.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         unsigned a[] = {3, 5, 7};
@@ -25,4 +25,6 @@ int main()
         std::linear_congruential_engine<unsigned, 5, 7, 11> e2(4);
         assert(e1 == e2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/default.pass.cpp
index 67846b06dd2..372d98a656c 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/default.pass.cpp
@@ -46,10 +46,12 @@ test()
     test1<T, M-1, M-1, M>();
 }
 
-int main()
+int main(int, char**)
 {
     test<unsigned short>();
     test<unsigned int>();
     test<unsigned long>();
     test<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/discard.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/discard.pass.cpp
index 4848a3d76f6..dcbb3e0656b 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/discard.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/discard.pass.cpp
@@ -56,7 +56,7 @@ other()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     rand0<unsigned int>();
     rand0<unsigned long>();
@@ -69,4 +69,6 @@ int main()
     other<unsigned int>();
     other<unsigned long>();
     other<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/eval.pass.cpp
index ec217f306f0..3ee4d9113ac 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/eval.pass.cpp
@@ -70,7 +70,7 @@ Haldir()
     assert(e() == 217250280);
 }
 
-int main()
+int main(int, char**)
 {
     randu<unsigned int>();
     randu<unsigned long>();
@@ -83,4 +83,6 @@ int main()
     Haldir<unsigned int>();
     Haldir<unsigned long>();
     Haldir<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/io.pass.cpp
index 04159baa5d7..b12de7b0190 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/io.pass.cpp
@@ -27,7 +27,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::linear_congruential_engine<unsigned, 48271, 0, 2147483647> E;
@@ -40,4 +40,6 @@ int main()
         is >> e2;
         assert(e1 == e2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/result_type.pass.cpp
index 569e76050b3..e0bb2e02cc1 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/result_type.pass.cpp
@@ -27,10 +27,12 @@ test()
         T>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<unsigned short>();
     test<unsigned int>();
     test<unsigned long>();
     test<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_result_type.pass.cpp
index da944061bff..3103bf7efb5 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_result_type.pass.cpp
@@ -30,10 +30,12 @@ test1()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1<unsigned short>();
     test1<unsigned int>();
     test1<unsigned long>();
     test1<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
index c3aec15f6d5..e7725bd0b58 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         unsigned a[] = {3, 5, 7};
@@ -35,4 +35,6 @@ int main()
         E e2(sseq);
         assert(e1 == e2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/values.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/values.pass.cpp
index b649b24bb4c..a8c86bad306 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/values.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/values.pass.cpp
@@ -85,10 +85,12 @@ test()
     test1<T, M-1, M-1, M>();
 }
 
-int main()
+int main(int, char**)
 {
     test<unsigned short>();
     test<unsigned int>();
     test<unsigned long>();
     test<unsigned long long>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/assign.pass.cpp
index 3ac6d303296..3e1002b061e 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/assign.pass.cpp
@@ -50,8 +50,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/copy.pass.cpp
index eb0486aa784..b1273f1bbc3 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/copy.pass.cpp
@@ -48,8 +48,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_result_type.pass.cpp
index ae89e6e79e7..4eca3baad32 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_result_type.pass.cpp
@@ -237,8 +237,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq.pass.cpp
index d695441cd68..b46029a2923 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq.pass.cpp
@@ -301,8 +301,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp
index 9f298ea4995..a2489cf6366 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp
@@ -71,10 +71,12 @@ void test(void) {
   assert(e() == X0);
 }
 
-int main() {
+int main(int, char**) {
   // Test for k == 1: word_size <= 32.
   test<unsigned short, 3u>();
 
   // Test for k == 2: (32 < word_size <= 64).
   test<unsigned long long, 33u>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/default.pass.cpp
index 2d91db790da..35364f312a9 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/default.pass.cpp
@@ -37,8 +37,10 @@ test2()
     assert(e1() == 14514284786278117030ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/discard.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/discard.pass.cpp
index 58d59975def..750afb1e8a1 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/discard.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/discard.pass.cpp
@@ -47,8 +47,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/eval.pass.cpp
index 9d44192f3f3..03e87dad8c4 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/eval.pass.cpp
@@ -37,8 +37,10 @@ test2()
     assert(e() == 13109570281517897720ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/io.pass.cpp
index 8f7c699ee65..cbc764e8dd6 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/io.pass.cpp
@@ -61,8 +61,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/result_type.pass.cpp
index ce0506043c9..7987d65748e 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/result_type.pass.cpp
@@ -36,8 +36,10 @@ test2()
         std::uint_fast64_t>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_result_type.pass.cpp
index ef529ffcf6b..ff7d07374cb 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_result_type.pass.cpp
@@ -44,8 +44,10 @@ test2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_sseq.pass.cpp
index 3d05ce779cf..8ad2ec289f6 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/seed_sseq.pass.cpp
@@ -42,8 +42,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/values.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/values.pass.cpp
index 62ac9f516a8..1af1d85b25f 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/values.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/values.pass.cpp
@@ -126,8 +126,10 @@ test2()
     where(E::default_seed);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/assign.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/assign.pass.cpp
index c05831165f8..e6cce1b2da7 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/assign.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/assign.pass.cpp
@@ -48,8 +48,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/copy.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/copy.pass.cpp
index 70a2b5b2cf7..c39f39858e4 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/copy.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/copy.pass.cpp
@@ -46,8 +46,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_result_type.pass.cpp
index 3045b06c92f..5a178e82e6f 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_result_type.pass.cpp
@@ -43,8 +43,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_sseq.pass.cpp
index 361a0fc25dd..0ed496e71af 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/ctor_sseq.pass.cpp
@@ -47,8 +47,10 @@ test2()
     assert(os.str() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/default.pass.cpp
index 13dede1aa94..dbc4c5b4cb8 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/default.pass.cpp
@@ -34,8 +34,10 @@ test2()
     assert(e1() == 23459059301164ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/discard.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/discard.pass.cpp
index f4824cd9a1c..4d039289bff 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/discard.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/discard.pass.cpp
@@ -44,8 +44,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/eval.pass.cpp
index 818d66c441e..d8d03c09ee5 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/eval.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/eval.pass.cpp
@@ -34,8 +34,10 @@ test2()
     assert(e() == 276846226770426ull);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/io.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/io.pass.cpp
index 88d0910d2e7..d3eeda3be4a 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/io.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/io.pass.cpp
@@ -55,8 +55,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/result_type.pass.cpp
index cc0fa903adc..5312bb1ff3a 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/result_type.pass.cpp
@@ -34,8 +34,10 @@ test2()
         std::uint_fast64_t>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_result_type.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_result_type.pass.cpp
index 201ec38d1e5..637841a679b 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_result_type.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_result_type.pass.cpp
@@ -42,8 +42,10 @@ test2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_sseq.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_sseq.pass.cpp
index 2a178388ce0..85199c0ef3b 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_sseq.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/seed_sseq.pass.cpp
@@ -40,8 +40,10 @@ test2()
     assert(e1 == e2);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/values.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/values.pass.cpp
index 758a5957f12..a877eff1383 100644
--- a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/values.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.sub/values.pass.cpp
@@ -74,8 +74,10 @@ test2()
     where(E::default_seed);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/default_random_engine.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/default_random_engine.pass.cpp
index a5b9334c617..b06cd465661 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/default_random_engine.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/default_random_engine.pass.cpp
@@ -15,9 +15,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::default_random_engine e;
     e.discard(9999);
     LIBCPP_ASSERT(e() == 399268537u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/knuth_b.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/knuth_b.pass.cpp
index a06bbe966ef..d81f788e5e0 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/knuth_b.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/knuth_b.pass.cpp
@@ -13,9 +13,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::knuth_b e;
     e.discard(9999);
     assert(e() == 1112339016u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/minstd_rand.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/minstd_rand.pass.cpp
index 9a44b4c0ab0..d38b009e5f8 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/minstd_rand.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/minstd_rand.pass.cpp
@@ -14,9 +14,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::minstd_rand e;
     e.discard(9999);
     assert(e() == 399268537u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/minstd_rand0.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/minstd_rand0.pass.cpp
index f676f5f00e9..4e4f07eae78 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/minstd_rand0.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/minstd_rand0.pass.cpp
@@ -14,9 +14,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::minstd_rand0 e;
     e.discard(9999);
     assert(e() == 1043618065u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/mt19937.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/mt19937.pass.cpp
index 28166616325..16390964f58 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/mt19937.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/mt19937.pass.cpp
@@ -18,9 +18,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::mt19937 e;
     e.discard(9999);
     assert(e() == 4123659995u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/mt19937_64.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/mt19937_64.pass.cpp
index 80ffb429e54..c6a3b4ebdf9 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/mt19937_64.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/mt19937_64.pass.cpp
@@ -18,9 +18,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::mt19937_64 e;
     e.discard(9999);
     assert(e() == 9981545732273789042ull);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/ranlux24.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/ranlux24.pass.cpp
index c58f09dcc80..9805d1add87 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/ranlux24.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/ranlux24.pass.cpp
@@ -13,9 +13,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ranlux24 e;
     e.discard(9999);
     assert(e() == 9901578u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/ranlux24_base.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/ranlux24_base.pass.cpp
index 30d94e69663..21c68699bfa 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/ranlux24_base.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/ranlux24_base.pass.cpp
@@ -13,9 +13,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ranlux24_base e;
     e.discard(9999);
     assert(e() == 7937952u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/ranlux48.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/ranlux48.pass.cpp
index 22c45db40b1..2ab37e1c728 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/ranlux48.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/ranlux48.pass.cpp
@@ -13,9 +13,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ranlux48 e;
     e.discard(9999);
     assert(e() == 249142670248501ull);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.predef/ranlux48_base.pass.cpp b/libcxx/test/std/numerics/rand/rand.predef/ranlux48_base.pass.cpp
index 8faefbb4cc2..93bb14c5c93 100644
--- a/libcxx/test/std/numerics/rand/rand.predef/ranlux48_base.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.predef/ranlux48_base.pass.cpp
@@ -13,9 +13,11 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ranlux48_base e;
     e.discard(9999);
     assert(e() == 61839128582725ull);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/rand.req.adapt/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/rand.req.adapt/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/rand.req.adapt/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/rand.req.adapt/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/rand.req.dst/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/rand.req.dst/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/rand.req.dst/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/rand.req.dst/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/rand.req.eng/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/rand.req.eng/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/rand.req.eng/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/rand.req.eng/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/rand.req.genl/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/rand.req.genl/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/rand.req.genl/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/rand.req.genl/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/rand.req.seedseq/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/rand.req.seedseq/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/rand.req.seedseq/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/rand.req.seedseq/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.req/rand.req.urng/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.req/rand.req.urng/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.req/rand.req.urng/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.req/rand.req.urng/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/nothing_to_do.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/numerics/rand/rand.util/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp
index 62e129b989f..a05c0846af7 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "truncate_fp.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::minstd_rand0 E;
@@ -98,4 +98,6 @@ int main()
             (282475249 - E::min()) * (E::max() - E::min() + F(1))) /
             ((E::max() - E::min() + F(1)) * (E::max() - E::min() + F(1)))));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/assign.fail.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/assign.fail.cpp
index f9a5bc05ecd..de06a5e9b57 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/assign.fail.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/assign.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <random>
 
-int main()
+int main(int, char**)
 {
     std::seed_seq s0;
     std::seed_seq s;
     s = s0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/copy.fail.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/copy.fail.cpp
index 5e6ed7a01d4..7c3c38ea7a1 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/copy.fail.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/copy.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <random>
 
-int main()
+int main(int, char**)
 {
     std::seed_seq s0;
     std::seed_seq s(s0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/default.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/default.pass.cpp
index 1002ea8a440..87608e63c04 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/default.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/default.pass.cpp
@@ -15,8 +15,10 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::seed_seq s;
     assert(s.size() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/generate.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/generate.pass.cpp
index db32abddc6f..e328777782b 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/generate.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/generate.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         // These numbers generated from a slightly altered version of dSFMT
@@ -801,4 +801,6 @@ int main()
         for (int i = 0; i < n; ++i)
             assert(a[i] == b[i]);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/initializer_list.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/initializer_list.pass.cpp
index 2d1656a3c03..656981b1a93 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/initializer_list.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::seed_seq s= {5, 4, 3, 2, 1};
     assert(s.size() == 5);
@@ -29,4 +29,6 @@ int main()
     assert(b[2] == 3);
     assert(b[3] == 2);
     assert(b[4] == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/iterator.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/iterator.pass.cpp
index 3b1a79ec395..10f7b34727e 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/iterator.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/iterator.pass.cpp
@@ -16,7 +16,7 @@
 #include <random>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     unsigned a[5] = {5, 4, 3, 2, 1};
     std::seed_seq s(a, a+5);
@@ -28,4 +28,6 @@ int main()
     assert(b[2] == 3);
     assert(b[3] == 2);
     assert(b[4] == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/types.pass.cpp b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/types.pass.cpp
index d169811db29..50cfa7d59cc 100644
--- a/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/types.pass.cpp
+++ b/libcxx/test/std/numerics/rand/rand.util/rand.util.seedseq/types.pass.cpp
@@ -17,7 +17,9 @@
 #include <random>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::seed_seq::result_type, std::uint_least32_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/nothing_to_do.pass.cpp b/libcxx/test/std/re/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.alg/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/re.alg/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.alg/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp
index 095980c6055..43fc9b89cb8 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1391,4 +1391,5 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/basic.fail.cpp b/libcxx/test/std/re/re.alg/re.alg.match/basic.fail.cpp
index bc5e4b75d93..d71fc280a29 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/basic.fail.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/basic.fail.cpp
@@ -25,11 +25,13 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::smatch m;
         std::regex re{"*"};
         std::regex_match(std::string("abcde"), m, re);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp
index d6a0b0da71d..b2fa6e94135 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1367,4 +1367,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp
index c1e910c77aa..e15533da6f3 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1391,4 +1391,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/egrep.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/egrep.pass.cpp
index 8789e7d7370..4e1b6940c09 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/egrep.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/egrep.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -78,4 +78,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == "tourna");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/exponential.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/exponential.pass.cpp
index f23bef36ec1..a1ba80f2681 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/exponential.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/exponential.pass.cpp
@@ -23,7 +23,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   for (std::regex_constants::syntax_option_type op :
        {std::regex::ECMAScript, std::regex::extended, std::regex::egrep,
         std::regex::awk}) {
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
index b04d750a3f3..9415505faaf 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1363,4 +1363,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/grep.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/grep.pass.cpp
index 0c68dca6983..0f75d618c0c 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/grep.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/grep.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -46,4 +46,6 @@ int main()
                 std::regex_constants::grep)));
         assert(m.size() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/inverted_character_classes.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/inverted_character_classes.pass.cpp
index 67bfd96f4dd..d48d86ee64c 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/inverted_character_classes.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/inverted_character_classes.pass.cpp
@@ -15,7 +15,7 @@
 #include <regex>
 
 
-int main() {
+int main(int, char**) {
     assert(std::regex_match("X", std::regex("[X]")));
     assert(std::regex_match("X", std::regex("[XY]")));
     assert(!std::regex_match("X", std::regex("[^X]")));
@@ -40,4 +40,6 @@ int main() {
     assert(!std::regex_match("_", std::regex("[\\W]")));
     assert(std::regex_match("X", std::regex("[^\\W]")));
     assert(std::regex_match("_", std::regex("[^\\W]")));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/lookahead_capture.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/lookahead_capture.pass.cpp
index ec8467f4e63..1550f372856 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/lookahead_capture.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/lookahead_capture.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex re("^(?=(.))a$");
@@ -95,4 +95,6 @@ int main()
         assert(m[3] == "a");
         assert(m[4] == "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/parse_curly_brackets.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/parse_curly_brackets.pass.cpp
index b6d3e1ae334..291798cfcc9 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/parse_curly_brackets.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/parse_curly_brackets.pass.cpp
@@ -62,10 +62,12 @@ test4()
     assert((std::regex_match(target, smatch, regex)));
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
     test3();
     test4();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/exponential.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/exponential.pass.cpp
index 715aa0affe4..868c3d8350b 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/exponential.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/exponential.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     try {
         std::regex re("a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?aaaaaaaaaaaaaaaaaaaa");
@@ -35,4 +35,5 @@ int main()
     } catch (const std::regex_error &e) {
       assert(e.code() == std::regex_constants::error_complexity);
     }
+    return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/test1.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/test1.pass.cpp
index df68aae9381..7e5332aaff8 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/test1.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/test1.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -104,4 +104,6 @@ int main()
         assert(r.base() == buf+12);
         assert(buf == std::string("123-555-1234"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/test2.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/test2.pass.cpp
index 1cfaec6797e..d5e3b64a3eb 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/test2.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/test2.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -104,4 +104,6 @@ int main()
         assert(r.base() == buf+12);
         assert(buf == std::string("123-555-1234"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/test3.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/test3.pass.cpp
index ebfb20d7bd5..09ecc53a9f9 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/test3.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/test3.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -70,4 +70,6 @@ int main()
                                            std::regex_constants::format_no_copy);
         assert(r == "123-555-1234");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/test4.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/test4.pass.cpp
index 88816e3d7ac..4d567ed1f64 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/test4.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/test4.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -69,4 +69,6 @@ int main()
                                            std::regex_constants::format_no_copy);
         assert(r == "123-555-1234");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/test5.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/test5.pass.cpp
index bcff51eddd1..585a60f8780 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/test5.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/test5.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -70,4 +70,6 @@ int main()
                                            std::regex_constants::format_no_copy);
         assert(r == "123-555-1234");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.replace/test6.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.replace/test6.pass.cpp
index 923230aea4b..66a910172c4 100644
--- a/libcxx/test/std/re/re.alg/re.alg.replace/test6.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.replace/test6.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -70,4 +70,6 @@ int main()
                                            std::regex_constants::format_no_copy);
         assert(r == "123-555-1234");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp
index 13f9646f42b..0f8fb14f586 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1574,4 +1574,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/backup.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/backup.pass.cpp
index 710cf226c97..d27124a8d80 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/backup.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/backup.pass.cpp
@@ -21,7 +21,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     // This regex_iterator uses regex_search(__wrap_iter<_Iter> __first, ...)
     // Test for https://bugs.llvm.org/show_bug.cgi?id=16240 fixed in r185273.
@@ -60,4 +60,6 @@ int main()
         ++it;
         assert(it == end);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/basic.fail.cpp b/libcxx/test/std/re/re.alg/re.alg.search/basic.fail.cpp
index d84b1c97bdc..fb9677f7e93 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/basic.fail.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/basic.fail.cpp
@@ -25,11 +25,13 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::smatch m;
         std::regex re{"*"};
         std::regex_search(std::string("abcde"), m, re);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp
index ee919b223b6..bd96c9830c0 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1547,4 +1547,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp
index afc5a005b6a..7e74caa0808 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1589,4 +1589,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/egrep.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/egrep.pass.cpp
index 4e329526088..df8560f5fa8 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/egrep.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/egrep.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -87,4 +87,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == "tourna");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/exponential.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/exponential.pass.cpp
index 6de3bbffd67..a9eb2b2b94e 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/exponential.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/exponential.pass.cpp
@@ -23,7 +23,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   for (std::regex_constants::syntax_option_type op :
        {std::regex::ECMAScript, std::regex::extended, std::regex::egrep,
         std::regex::awk}) {
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
index 6c9cabeff24..62e4822dbd1 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -1543,4 +1543,6 @@ int main()
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/grep.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/grep.pass.cpp
index 8844b4e6fb9..29300a81811 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/grep.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/grep.pass.cpp
@@ -50,7 +50,7 @@ void fuzz_tests()  // patterns that the fuzzer has found
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::cmatch m;
@@ -85,4 +85,6 @@ int main()
         assert(m.str(0) == "");
     }
     fuzz_tests();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/invert_neg_word_search.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/invert_neg_word_search.pass.cpp
index 98343f55401..63fd5ae57ae 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/invert_neg_word_search.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/invert_neg_word_search.pass.cpp
@@ -20,7 +20,7 @@
 
 
 // PR34310
-int main()
+int main(int, char**)
 {
   assert(std::regex_search("HelloWorld", std::regex("[^\\W]")));
   assert(std::regex_search("_", std::regex("[^\\W]")));
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/lookahead.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/lookahead.pass.cpp
index b4a47f09b9e..7846eca2abe 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/lookahead.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/lookahead.pass.cpp
@@ -21,8 +21,10 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(!std::regex_search("ab", std::regex("(?=^)b")));
     assert(!std::regex_search("ab", std::regex("a(?=^)b")));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/no_update_pos.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/no_update_pos.pass.cpp
index 8bfcfa007fb..73158dc53c9 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/no_update_pos.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/no_update_pos.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     // Iterating over /^a/ should yield one instance at the beginning
     // of the text.
@@ -35,4 +35,6 @@ int main()
 
     ++it;
     assert(it == end);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.alg/re.except/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.alg/re.except/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/re.alg/re.except/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.except/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.badexp/regex_error.pass.cpp b/libcxx/test/std/re/re.badexp/regex_error.pass.cpp
index efcc44f6a46..a3f4476b05d 100644
--- a/libcxx/test/std/re/re.badexp/regex_error.pass.cpp
+++ b/libcxx/test/std/re/re.badexp/regex_error.pass.cpp
@@ -21,7 +21,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_error e(std::regex_constants::error_collate);
@@ -93,4 +93,6 @@ int main()
         assert(e.what() == std::string("There was insufficient memory to determine whether the regular "
                "expression could match the specified character sequence."));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.const/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.const/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.const/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.const/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.const/re.err/error_type.pass.cpp b/libcxx/test/std/re/re.const/re.err/error_type.pass.cpp
index 4369e01706a..51979a5113f 100644
--- a/libcxx/test/std/re/re.const/re.err/error_type.pass.cpp
+++ b/libcxx/test/std/re/re.const/re.err/error_type.pass.cpp
@@ -35,7 +35,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::regex_constants::error_collate != 0);
     assert(std::regex_constants::error_ctype != 0);
@@ -140,4 +140,6 @@ int main()
     assert(std::regex_constants::error_badrepeat != std::regex_constants::error_stack);
 
     assert(std::regex_constants::error_complexity != std::regex_constants::error_stack);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.const/re.matchflag/match_flag_type.pass.cpp b/libcxx/test/std/re/re.const/re.matchflag/match_flag_type.pass.cpp
index bed42547bca..812601463c1 100644
--- a/libcxx/test/std/re/re.const/re.matchflag/match_flag_type.pass.cpp
+++ b/libcxx/test/std/re/re.const/re.matchflag/match_flag_type.pass.cpp
@@ -35,7 +35,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::regex_constants::match_default == 0);
     assert(std::regex_constants::match_not_bol != 0);
@@ -125,4 +125,6 @@ int main()
     e1 &= e2;
     e1 |= e2;
     e1 ^= e2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.const/re.matchflag/match_not_bol.pass.cpp b/libcxx/test/std/re/re.const/re.matchflag/match_not_bol.pass.cpp
index e3273663042..82395e2f2d4 100644
--- a/libcxx/test/std/re/re.const/re.matchflag/match_not_bol.pass.cpp
+++ b/libcxx/test/std/re/re.const/re.matchflag/match_not_bol.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::string target = "foo";
@@ -47,4 +47,6 @@ int main()
     assert( std::regex_search(target, re));
     assert( std::regex_search(target, re, std::regex_constants::match_not_bol));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.const/re.matchflag/match_not_eol.pass.cpp b/libcxx/test/std/re/re.const/re.matchflag/match_not_eol.pass.cpp
index 3d238c5d019..8b13c68bcc3 100644
--- a/libcxx/test/std/re/re.const/re.matchflag/match_not_eol.pass.cpp
+++ b/libcxx/test/std/re/re.const/re.matchflag/match_not_eol.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::string target = "foo";
@@ -47,4 +47,6 @@ int main()
     assert( std::regex_search(target, re));
     assert( std::regex_search(target, re, std::regex_constants::match_not_eol));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.const/re.matchflag/match_not_null.pass.cpp b/libcxx/test/std/re/re.const/re.matchflag/match_not_null.pass.cpp
index d3389e6b653..645f79a0d85 100644
--- a/libcxx/test/std/re/re.const/re.matchflag/match_not_null.pass.cpp
+++ b/libcxx/test/std/re/re.const/re.matchflag/match_not_null.pass.cpp
@@ -15,7 +15,7 @@
 #include <cassert>
 #include <regex>
 
-int main()
+int main(int, char**)
 {
   // When match_not_null is on, the regex engine should reject empty matches and
   // move on to try other solutions.
diff --git a/libcxx/test/std/re/re.const/re.synopt/syntax_option_type.pass.cpp b/libcxx/test/std/re/re.const/re.synopt/syntax_option_type.pass.cpp
index 7af7e8cf4d1..49ce2b5c482 100644
--- a/libcxx/test/std/re/re.const/re.synopt/syntax_option_type.pass.cpp
+++ b/libcxx/test/std/re/re.const/re.synopt/syntax_option_type.pass.cpp
@@ -32,7 +32,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::regex_constants::icase != 0);
     assert(std::regex_constants::nosubs != 0);
@@ -111,4 +111,6 @@ int main()
     e1 &= e2;
     e1 |= e2;
     e1 ^= e2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.collating.element/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.collating.element/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.collating.element/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.collating.element/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.finite.state.machine/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.finite.state.machine/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.finite.state.machine/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.finite.state.machine/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.format.specifier/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.format.specifier/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.format.specifier/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.format.specifier/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.matched/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.matched/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.matched/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.matched/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.primary.equivalence.class/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.primary.equivalence.class/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.primary.equivalence.class/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.primary.equivalence.class/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.regular.expression/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.regular.expression/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.regular.expression/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.regular.expression/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/defns.regex.subexpression/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/defns.regex.subexpression/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/defns.regex.subexpression/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/defns.regex.subexpression/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.def/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.def/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.def/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.def/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.general/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.general/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.general/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.grammar/excessive_brace_count.pass.cpp b/libcxx/test/std/re/re.grammar/excessive_brace_count.pass.cpp
index 49bd06e5cac..a5f28d2eec0 100644
--- a/libcxx/test/std/re/re.grammar/excessive_brace_count.pass.cpp
+++ b/libcxx/test/std/re/re.grammar/excessive_brace_count.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
   for (std::regex_constants::syntax_option_type op :
        {std::regex::basic, std::regex::grep}) {
     try {
diff --git a/libcxx/test/std/re/re.grammar/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.grammar/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/re.grammar/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.grammar/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.iter/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/re.iter/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.iter/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.fail.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.fail.cpp
index 17cce2cb4c4..34d1ce6ed8e 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.fail.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.fail.cpp
@@ -24,7 +24,7 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         const char phone_book[] = "555-1234, 555-2345, 555-3456";
@@ -32,4 +32,6 @@ int main()
             std::begin(phone_book), std::end(phone_book),
             std::regex("\\d{3}-\\d{4}"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.pass.cpp
index d944806fded..a6d10597451 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/cnstr.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -41,4 +41,6 @@ int main()
         ++i;
         assert(i == std::cregex_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/default.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/default.pass.cpp
index ca5670bbb47..75bd9cab5f2 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/default.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.cnstr/default.pass.cpp
@@ -25,8 +25,10 @@ test()
     assert(i1 == I());
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.comp/tested_elsewhere.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.comp/tested_elsewhere.pass.cpp
index 55b506be101..f7f71bc8b7c 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.comp/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.comp/tested_elsewhere.pass.cpp
@@ -13,6 +13,8 @@
 // bool operator==(const regex_iterator& right) const;
 // bool operator!=(const regex_iterator& right) const;
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.deref/deref.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.deref/deref.pass.cpp
index 2643cebc76b..11b12b2eef8 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.deref/deref.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.deref/deref.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -39,4 +39,6 @@ int main()
         ++i;
         assert(i == std::cregex_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp
index be4126e3e33..ad65f7c13b4 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -112,4 +112,6 @@ int main()
         ++i;
         assert(i == e);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.regiter/types.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/types.pass.cpp
index 07c3fa64bc7..b96fec78a3c 100644
--- a/libcxx/test/std/re/re.iter/re.regiter/types.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/types.pass.cpp
@@ -38,8 +38,10 @@ test()
     static_assert((std::is_same<typename I::iterator_category, std::forward_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.fail.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.fail.cpp
index bddf58210c5..a03fd52c035 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.fail.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.fail.cpp
@@ -26,7 +26,7 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-(\\d{4})");
@@ -35,4 +35,6 @@ int main()
         std::cregex_token_iterator i(std::begin(phone_book), std::end(phone_book)-1,
                                      std::regex("\\d{3}-\\d{4}"), indices);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp
index eadfbdb44d4..254909a92e0 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp
@@ -21,7 +21,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-(\\d{4})");
@@ -61,4 +61,6 @@ int main()
         ++i;
         assert(i == std::cregex_token_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/default.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/default.pass.cpp
index cdbf1a5917d..bb70095f139 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/default.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/default.pass.cpp
@@ -25,8 +25,10 @@ test()
     assert(i1 == I());
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.fail.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.fail.cpp
index 87a227af058..b6913e6b32d 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.fail.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.fail.cpp
@@ -24,7 +24,7 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-(\\d{4})");
@@ -32,4 +32,6 @@ int main()
         std::cregex_token_iterator i(std::begin(phone_book), std::end(phone_book)-1,
                                       std::regex("\\d{3}-\\d{4}"), {-1, 0, 1});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp
index 8ecd0bab44f..322c2682daf 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp
@@ -22,7 +22,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-(\\d{4})");
@@ -61,4 +61,6 @@ int main()
         ++i;
         assert(i == std::cregex_token_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.fail.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.fail.cpp
index 82e0678182f..3c39d4983e2 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.fail.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.fail.cpp
@@ -23,7 +23,7 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -31,4 +31,6 @@ int main()
         std::cregex_token_iterator i(std::begin(phone_book), std::end(phone_book)-1,
                                      std::regex("\\d{3}-\\d{4}"), -1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp
index c2213a0af48..1e5ba2eca12 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -72,4 +72,6 @@ int main()
         ++i;
         assert(i == std::cregex_token_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.fail.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.fail.cpp
index 9e8fe86ed28..9b07df9d1a7 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.fail.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.fail.cpp
@@ -25,7 +25,7 @@
 #error
 #endif
 
-int main()
+int main(int, char**)
 {
     {
          std::regex phone_numbers("\\d{3}-(\\d{4})");
@@ -36,4 +36,6 @@ int main()
         std::cregex_token_iterator i(std::begin(phone_book), std::end(phone_book)-1,
                                      std::regex("\\d{3}-\\d{4}"), v);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp
index 5f31c579533..1d77deb9185 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-(\\d{4})");
@@ -125,4 +125,6 @@ int main()
         ++i;
         assert(i == std::cregex_token_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.comp/equal.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.comp/equal.pass.cpp
index f4de410b211..1c602010319 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.comp/equal.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.comp/equal.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -33,4 +33,6 @@ int main()
         assert(!(i2 == i));
         assert(i2 != i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp
index edde79c1641..facd243675b 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -69,4 +69,6 @@ int main()
         ++i;
         assert(i == std::cregex_token_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp
index c4095ebf6ec..15f1bb7c851 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex phone_numbers("\\d{3}-\\d{4}");
@@ -132,4 +132,6 @@ int main()
         i++;
         assert(i == std::cregex_token_iterator());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/types.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/types.pass.cpp
index 58803aa1ad3..73ad58f4eec 100644
--- a/libcxx/test/std/re/re.iter/re.tokiter/types.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/types.pass.cpp
@@ -38,8 +38,10 @@ test()
     static_assert((std::is_same<typename I::iterator_category, std::forward_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/assign.il.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/assign.il.pass.cpp
index daaac65bed6..532a72073e6 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/assign.il.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/assign.il.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2.assign({'(', 'a', '(', '[', 'b', 'c', ']', ')', ')'});
@@ -30,4 +30,6 @@ int main()
     r2.assign({'(', 'a', '(', '[', 'b', 'c', ']', ')', ')'}, std::regex::extended);
     assert(r2.flags() == std::regex::extended);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/assign.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/assign.pass.cpp
index 9507ea31012..c580ab96cba 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/assign.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/assign.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r1("(a([bc]))");
     std::regex r2;
@@ -34,4 +34,6 @@ int main()
     assert(r2.mark_count() == 2);
     assert(std::regex_search("ab", r2));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/assign_iter_iter_flag.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/assign_iter_iter_flag.pass.cpp
index 9eba95b33bf..dd32c9466df 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/assign_iter_iter_flag.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/assign_iter_iter_flag.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     typedef input_iterator<std::string::const_iterator> I;
     typedef forward_iterator<std::string::const_iterator> F;
@@ -43,4 +43,6 @@ int main()
     r2.assign(F(s4.begin()), F(s4.end()), std::regex::extended);
     assert(r2.flags() == std::regex::extended);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_flag.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_flag.pass.cpp
index 30c7281dacc..9445bbaf9ff 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_flag.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_flag.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2.assign("(a([bc]))");
@@ -26,4 +26,6 @@ int main()
     r2.assign("(a([bc]))", std::regex::extended);
     assert(r2.flags() == std::regex::extended);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_size_flag.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_size_flag.pass.cpp
index 08fdf871dcc..cdbdae43054 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_size_flag.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/assign_ptr_size_flag.pass.cpp
@@ -16,10 +16,12 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2.assign("(a([bc]))", 9, std::regex::extended);
     assert(r2.flags() == std::regex::extended);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/assign_string_flag.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/assign_string_flag.pass.cpp
index 7ea385967c3..4b1bcef9a6b 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/assign_string_flag.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/assign_string_flag.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2.assign(std::string("(a([bc]))"));
@@ -28,4 +28,6 @@ int main()
     r2.assign(std::string("(a([bc]))"), std::regex::extended);
     assert(r2.flags() == std::regex::extended);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/copy.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/copy.pass.cpp
index c74f0a6f029..1abb7215165 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/copy.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/copy.pass.cpp
@@ -16,11 +16,13 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r1("(a([bc]))");
     std::regex r2;
     r2 = r1;
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/il.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/il.pass.cpp
index 75803e6002d..880fd5c79c8 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/il.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/il.pass.cpp
@@ -18,10 +18,12 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2 = {'(', 'a', '(', '[', 'b', 'c', ']', ')', ')'};
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/ptr.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/ptr.pass.cpp
index f2ca05a9bfe..3791f815272 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/ptr.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/ptr.pass.cpp
@@ -16,10 +16,12 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2 = "(a([bc]))";
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.assign/string.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.assign/string.pass.cpp
index 3cb8e8b41be..e33819ab3c3 100644
--- a/libcxx/test/std/re/re.regex/re.regex.assign/string.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.assign/string.pass.cpp
@@ -17,10 +17,12 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r2;
     r2 = std::string("(a([bc]))");
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.const/constants.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.const/constants.pass.cpp
index 3fc28e4ec9b..5d8d48d0590 100644
--- a/libcxx/test/std/re/re.regex/re.regex.const/constants.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.const/constants.pass.cpp
@@ -58,8 +58,10 @@ test()
     where(BR::egrep);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/awk_oct.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/awk_oct.pass.cpp
index eabf8eab9f2..2e7eed350c0 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/awk_oct.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/awk_oct.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::regex_constants::awk;
 
@@ -25,4 +25,6 @@ int main()
     assert(std::regex_match("\41", std::regex("\\41", awk)));
     assert(std::regex_match("\141", std::regex("\\141", awk)));
     assert(std::regex_match("\141" "1", std::regex("\\1411", awk)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/bad_backref.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/bad_backref.pass.cpp
index cc1b081c7df..0a15b6453c8 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/bad_backref.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/bad_backref.pass.cpp
@@ -29,7 +29,7 @@ static bool error_badbackref_thrown(const char *pat)
     return result;
 }
 
-int main()
+int main(int, char**)
 {
     assert(error_badbackref_thrown("\\1abc"));      // no references
     assert(error_badbackref_thrown("ab(c)\\2def")); // only one reference
@@ -41,4 +41,6 @@ int main()
     const char *pat1 = "a(b)c\\1234";
     std::regex re(pat1, pat1 + 7); // extra chars after the end.
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/bad_ctype.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/bad_ctype.pass.cpp
index dc24531cb48..5752d5cd681 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/bad_ctype.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/bad_ctype.pass.cpp
@@ -29,8 +29,10 @@ static bool error_ctype_thrown(const char *pat)
     return result;
 }
 
-int main()
+int main(int, char**)
 {
     assert(error_ctype_thrown("[[::]]"));
     assert(error_ctype_thrown("[[:error:]]"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
index f9e589ce7c7..041d55bdf88 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
@@ -29,7 +29,7 @@ static bool error_escape_thrown(const char *pat)
     return result;
 }
 
-int main()
+int main(int, char**)
 {
     assert(error_escape_thrown("[\\a]"));
     assert(error_escape_thrown("\\a"));
@@ -44,4 +44,6 @@ int main()
     assert(!error_escape_thrown("[\\cA]"));
     assert(!error_escape_thrown("\\cA"));
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/bad_repeat.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/bad_repeat.pass.cpp
index 2d07e1e8cf3..1af8b5ba651 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/bad_repeat.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/bad_repeat.pass.cpp
@@ -29,7 +29,7 @@ static bool error_badrepeat_thrown(const char *pat)
     return result;
 }
 
-int main()
+int main(int, char**)
 {
     assert(error_badrepeat_thrown("?a"));
     assert(error_badrepeat_thrown("*a"));
@@ -40,4 +40,6 @@ int main()
     assert(error_badrepeat_thrown("*(a+)"));
     assert(error_badrepeat_thrown("+(a+)"));
     assert(error_badrepeat_thrown("{(a+)"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/copy.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/copy.pass.cpp
index 588f673bf4f..f3db8fe0611 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/copy.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/copy.pass.cpp
@@ -16,10 +16,12 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r1("(a([bc]))");
     std::regex r2 = r1;
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/deduct.fail.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/deduct.fail.cpp
index 5ece59ad263..30ec49c833b 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/deduct.fail.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/deduct.fail.cpp
@@ -24,7 +24,7 @@
 #include <cstddef>
 
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -41,4 +41,6 @@ int main()
 
 //  Test the implicit deduction guides
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/deduct.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/deduct.pass.cpp
index 5d7493ae640..47e5a1dba7f 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/deduct.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/deduct.pass.cpp
@@ -31,7 +31,7 @@ using namespace std::literals;
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 
 //  Test the explicit deduction guides
@@ -133,4 +133,6 @@ int main()
     assert(re.flags() == std::regex_constants::grep);
     assert(re.mark_count() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/default.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/default.pass.cpp
index b5c1521fce5..f706229e683 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/default.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/default.pass.cpp
@@ -25,8 +25,10 @@ test()
     assert(r.mark_count() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/il_flg.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/il_flg.pass.cpp
index aac13147e81..aaf5bc25a7c 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/il_flg.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/il_flg.pass.cpp
@@ -29,7 +29,7 @@ test(std::initializer_list<char> il, std::regex_constants::syntax_option_type f,
 }
 
 
-int main()
+int main(int, char**)
 {
     std::string s1("\\(a\\)");
     std::string s2("\\(a[bc]\\)");
@@ -65,4 +65,6 @@ int main()
     test({'\\', '(', 'a', '[', 'b', 'c', ']', '\\', ')'}, std::regex_constants::egrep, 0);
     test({'\\', '(', 'a', '\\', '(', '[', 'b', 'c', ']', '\\', ')', '\\', ')'}, std::regex_constants::egrep, 0);
     test({'(', 'a', '(', '[', 'b', 'c', ']', ')', ')'}, std::regex_constants::egrep, 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter.pass.cpp
index 0b5d0c50413..3dcf29fa009 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter.pass.cpp
@@ -28,7 +28,7 @@ test(Iter first, Iter last, unsigned mc)
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     typedef forward_iterator<std::string::const_iterator> F;
     std::string s1("\\(a\\)");
@@ -40,4 +40,6 @@ int main()
     test(F(s2.begin()), F(s2.end()), 0);
     test(F(s3.begin()), F(s3.end()), 0);
     test(F(s4.begin()), F(s4.end()), 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter_flg.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter_flg.pass.cpp
index 37878347f95..22423c09282 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter_flg.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/iter_iter_flg.pass.cpp
@@ -29,7 +29,7 @@ test(Iter first, Iter last, std::regex_constants::syntax_option_type f, unsigned
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     typedef forward_iterator<std::string::const_iterator> F;
     std::string s1("\\(a\\)");
@@ -66,4 +66,6 @@ int main()
     test(F(s2.begin()), F(s2.end()), std::regex_constants::egrep, 0);
     test(F(s3.begin()), F(s3.end()), std::regex_constants::egrep, 0);
     test(F(s4.begin()), F(s4.end()), std::regex_constants::egrep, 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/ptr.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/ptr.pass.cpp
index 877b9a4c6ee..b71d9eb7f49 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/ptr.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/ptr.pass.cpp
@@ -25,10 +25,12 @@ test(const CharT* p, unsigned mc)
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     test("\\(a\\)", 0);
     test("\\(a[bc]\\)", 0);
     test("\\(a\\([bc]\\)\\)", 0);
     test("(a([bc]))", 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/ptr_flg.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/ptr_flg.pass.cpp
index 998f28db892..e918b03116b 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/ptr_flg.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/ptr_flg.pass.cpp
@@ -25,7 +25,7 @@ test(const CharT* p, std::regex_constants::syntax_option_type f, unsigned mc)
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     test("\\(a\\)", std::regex_constants::basic, 1);
     test("\\(a[bc]\\)", std::regex_constants::basic, 1);
@@ -56,4 +56,6 @@ int main()
     test("\\(a[bc]\\)", std::regex_constants::egrep, 0);
     test("\\(a\\([bc]\\)\\)", std::regex_constants::egrep, 0);
     test("(a([bc]))", std::regex_constants::egrep, 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size.pass.cpp
index 03a53b76979..29fa3ca57ac 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size.pass.cpp
@@ -24,7 +24,7 @@ test(const CharT* p, std::size_t len, unsigned mc)
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     test("\\(a\\)", 5, 0);
     test("\\(a[bc]\\)", 9, 0);
@@ -35,4 +35,6 @@ int main()
     test("(\0)(b)(c)(d)", 9, 3);
     test("(\0)(b)(c)(d)", 3, 1);
     test("(\0)(b)(c)(d)", 0, 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size_flg.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size_flg.pass.cpp
index 8546c167355..07f3947318e 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size_flg.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/ptr_size_flg.pass.cpp
@@ -26,7 +26,7 @@ test(const CharT* p, std::size_t len, std::regex_constants::syntax_option_type f
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     test("\\(a\\)", 5, std::regex_constants::basic, 1);
     test("\\(a[bc]\\)", 9, std::regex_constants::basic, 1);
@@ -57,4 +57,6 @@ int main()
     test("\\(a[bc]\\)", 9, std::regex_constants::egrep, 0);
     test("\\(a\\([bc]\\)\\)", 13, std::regex_constants::egrep, 0);
     test("(a([bc]))", 9, std::regex_constants::egrep, 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/string.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/string.pass.cpp
index 58f607183e9..ecd0451d82b 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/string.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/string.pass.cpp
@@ -26,10 +26,12 @@ test(const String& p, unsigned mc)
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::string("\\(a\\)"), 0);
     test(std::string("\\(a[bc]\\)"), 0);
     test(std::string("\\(a\\([bc]\\)\\)"), 0);
     test(std::string("(a([bc]))"), 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/string_flg.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/string_flg.pass.cpp
index 6d504db3334..b6bd8c53c5a 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/string_flg.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/string_flg.pass.cpp
@@ -27,7 +27,7 @@ test(const String& p, std::regex_constants::syntax_option_type f, unsigned mc)
     assert(r.mark_count() == mc);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::string("\\(a\\)"), std::regex_constants::basic, 1);
     test(std::string("\\(a[bc]\\)"), std::regex_constants::basic, 1);
@@ -58,4 +58,6 @@ int main()
     test(std::string("\\(a[bc]\\)"), std::regex_constants::egrep, 0);
     test(std::string("\\(a\\([bc]\\)\\)"), std::regex_constants::egrep, 0);
     test(std::string("(a([bc]))"), std::regex_constants::egrep, 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.locale/imbue.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.locale/imbue.pass.cpp
index a985a74e945..27647f1238b 100644
--- a/libcxx/test/std/re/re.regex/re.regex.locale/imbue.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.locale/imbue.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     std::regex r;
     std::locale loc = r.imbue(std::locale(LOCALE_en_US_UTF_8));
@@ -30,4 +30,6 @@ int main()
     loc = r.imbue(std::locale("C"));
     assert(loc.name() == LOCALE_en_US_UTF_8);
     assert(r.getloc().name() == "C");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.nonmemb/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.nonmemb/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/re.regex/re.regex.nonmemb/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.nonmemb/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.nonmemb/re.regex.nmswap/swap.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.nonmemb/re.regex.nmswap/swap.pass.cpp
index dc5ad95cb0f..bb3291be6f0 100644
--- a/libcxx/test/std/re/re.regex/re.regex.nonmemb/re.regex.nmswap/swap.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.nonmemb/re.regex.nmswap/swap.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r1("(a([bc]))");
     std::regex r2;
@@ -26,4 +26,6 @@ int main()
     assert(r1.mark_count() == 0);
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.operations/tested_elsewhere.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.operations/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/re/re.regex/re.regex.operations/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.operations/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/re.regex.swap/swap.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.swap/swap.pass.cpp
index b519edc256b..5092d57c148 100644
--- a/libcxx/test/std/re/re.regex/re.regex.swap/swap.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.swap/swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::regex r1("(a([bc]))");
     std::regex r2;
@@ -25,4 +25,6 @@ int main()
     assert(r1.mark_count() == 0);
     assert(r2.flags() == std::regex::ECMAScript);
     assert(r2.mark_count() == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.regex/types.pass.cpp b/libcxx/test/std/re/re.regex/types.pass.cpp
index 21a563890af..a13ad180d3c 100644
--- a/libcxx/test/std/re/re.regex/types.pass.cpp
+++ b/libcxx/test/std/re/re.regex/types.pass.cpp
@@ -23,7 +23,7 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::basic_regex<char>::value_type, char>::value), "");
     static_assert((std::is_same<std::basic_regex<char>::traits_type, std::regex_traits<char> >::value), "");
@@ -38,4 +38,6 @@ int main()
     static_assert((std::is_same<std::basic_regex<wchar_t>::flag_type,
                                 std::regex_constants::syntax_option_type>::value), "");
     static_assert((std::is_same<std::basic_regex<wchar_t>::locale_type, std::locale>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.req/nothing_to_do.pass.cpp b/libcxx/test/std/re/re.req/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/re/re.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/re/re.req/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/begin_end.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/begin_end.pass.cpp
index d83ef300f81..48fff58b019 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/begin_end.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/begin_end.pass.cpp
@@ -33,7 +33,9 @@ test()
         assert(*i == m[j]);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/cbegin_cend.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/cbegin_cend.pass.cpp
index 9b8db258777..bd9009a8a44 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/cbegin_cend.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/cbegin_cend.pass.cpp
@@ -33,7 +33,9 @@ test()
         assert(*i == m[j]);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/index.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/index.pass.cpp
index e3f6215e9f4..a5c25a82c81 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/index.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/index.pass.cpp
@@ -46,8 +46,10 @@ test(std::regex_constants::syntax_option_type syntax)
     assert(m[4].matched == false);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::regex_constants::ECMAScript);
     test(std::regex_constants::extended);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/length.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/length.pass.cpp
index d7d68c5e032..266ba692ff4 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/length.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/length.pass.cpp
@@ -30,7 +30,9 @@ test()
     assert(m.length(4) == m[4].length());
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/position.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/position.pass.cpp
index 18aa79a4892..34256de3585 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/position.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/position.pass.cpp
@@ -30,7 +30,9 @@ test()
     assert(m.position(4) == std::distance(s, m[4].first));
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/prefix.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/prefix.pass.cpp
index ab389cc4536..b2cd48d4db6 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/prefix.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/prefix.pass.cpp
@@ -28,7 +28,9 @@ test()
     assert(m.prefix().matched == true);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/str.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/str.pass.cpp
index ae5f5c7f652..ae4387d463a 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/str.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/str.pass.cpp
@@ -30,7 +30,9 @@ test()
     assert(m.str(4) == std::string(m[4]));
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.acc/suffix.pass.cpp b/libcxx/test/std/re/re.results/re.results.acc/suffix.pass.cpp
index 7e88ab106d1..c9d3855e9bd 100644
--- a/libcxx/test/std/re/re.results/re.results.acc/suffix.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.acc/suffix.pass.cpp
@@ -28,7 +28,9 @@ test()
     assert(m.suffix().matched == true);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.all/get_allocator.pass.cpp b/libcxx/test/std/re/re.results/re.results.all/get_allocator.pass.cpp
index 1e0a3ce27c8..f0dcd7b6d42 100644
--- a/libcxx/test/std/re/re.results/re.results.all/get_allocator.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.all/get_allocator.pass.cpp
@@ -28,8 +28,10 @@ test(const Allocator& a)
     assert(m.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>(test_allocator<std::sub_match<const char*> >(3));
     test<wchar_t>(test_allocator<std::sub_match<const wchar_t*> >(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.const/allocator.pass.cpp b/libcxx/test/std/re/re.results/re.results.const/allocator.pass.cpp
index f8a5a83fed8..99ecb667b75 100644
--- a/libcxx/test/std/re/re.results/re.results.const/allocator.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.const/allocator.pass.cpp
@@ -28,8 +28,10 @@ test(const Allocator& a)
     assert(m.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>(test_allocator<std::sub_match<const char*> >(3));
     test<wchar_t>(test_allocator<std::sub_match<const wchar_t*> >(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.const/copy.pass.cpp b/libcxx/test/std/re/re.results/re.results.const/copy.pass.cpp
index f6733bdd148..a1dbea0e840 100644
--- a/libcxx/test/std/re/re.results/re.results.const/copy.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.const/copy.pass.cpp
@@ -30,11 +30,13 @@ test(const Allocator& a)
     assert(m1.get_allocator() == m0.get_allocator());
 }
 
-int main()
+int main(int, char**)
 {
     test<char>   (std::allocator<std::sub_match<const char *> >());
     test<wchar_t>(std::allocator<std::sub_match<const wchar_t *> >());
 
     test<char>   (test_allocator<std::sub_match<const char*> >(3));
     test<wchar_t>(test_allocator<std::sub_match<const wchar_t*> >(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.const/copy_assign.pass.cpp b/libcxx/test/std/re/re.results/re.results.const/copy_assign.pass.cpp
index 3429b066bee..943037e752f 100644
--- a/libcxx/test/std/re/re.results/re.results.const/copy_assign.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.const/copy_assign.pass.cpp
@@ -34,7 +34,7 @@ test(const Allocator& a)
         assert(m1.get_allocator() == Allocator());
 }
 
-int main()
+int main(int, char**)
 {
     test<char>   (std::allocator<std::sub_match<const char *> >());
     test<wchar_t>(std::allocator<std::sub_match<const wchar_t *> >());
@@ -46,4 +46,6 @@ int main()
 //  other_allocator has POCCA -> true
     test<char>   (other_allocator<std::sub_match<const char*> >(3));
     test<wchar_t>(other_allocator<std::sub_match<const wchar_t*> >(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.const/default.pass.cpp b/libcxx/test/std/re/re.results/re.results.const/default.pass.cpp
index 80f4a0269eb..a70c3441db3 100644
--- a/libcxx/test/std/re/re.results/re.results.const/default.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.const/default.pass.cpp
@@ -26,8 +26,10 @@ test()
     assert(m.get_allocator() == std::allocator<std::sub_match<const CharT*> >());
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.const/move.pass.cpp b/libcxx/test/std/re/re.results/re.results.const/move.pass.cpp
index b3d2a0f4179..778e31b26f7 100644
--- a/libcxx/test/std/re/re.results/re.results.const/move.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.const/move.pass.cpp
@@ -35,7 +35,7 @@ test(const Allocator& a)
     assert(m1.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>   (std::allocator<std::sub_match<const char *> >());
     test<wchar_t>(std::allocator<std::sub_match<const wchar_t *> >());
@@ -44,4 +44,6 @@ int main()
     assert(test_alloc_base::moved == 1);
     test<wchar_t>(test_allocator<std::sub_match<const wchar_t*> >(3));
     assert(test_alloc_base::moved == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.const/move_assign.pass.cpp b/libcxx/test/std/re/re.results/re.results.const/move_assign.pass.cpp
index 55c66e9e196..2a62af8f297 100644
--- a/libcxx/test/std/re/re.results/re.results.const/move_assign.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.const/move_assign.pass.cpp
@@ -35,7 +35,7 @@ test(const Allocator& a)
         assert(m1.get_allocator() == Allocator());
 }
 
-int main()
+int main(int, char**)
 {
     test<char>   (std::allocator<std::sub_match<const char *> >());
     test<wchar_t>(std::allocator<std::sub_match<const wchar_t *> >());
@@ -47,4 +47,6 @@ int main()
 //  other_allocator has POCMA -> true
     test<char>   (other_allocator<std::sub_match<const char*> >(3));
     test<wchar_t>(other_allocator<std::sub_match<const wchar_t*> >(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.form/form1.pass.cpp b/libcxx/test/std/re/re.results/re.results.form/form1.pass.cpp
index 6046f9be095..f435de8276b 100644
--- a/libcxx/test/std/re/re.results/re.results.form/form1.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.form/form1.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_iterators.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::match_results<const char*> m;
@@ -152,4 +152,6 @@ int main()
         assert(r == out + 34);
         assert(std::wstring(out) == L"match: cdefghi, m[1]: efg, m[2]: e");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.form/form2.pass.cpp b/libcxx/test/std/re/re.results/re.results.form/form2.pass.cpp
index 2c9d30eb2e2..b28c064e105 100644
--- a/libcxx/test/std/re/re.results/re.results.form/form2.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.form/form2.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_iterators.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::basic_string<char, std::char_traits<char>, test_allocator<char> > nstr;
     typedef std::basic_string<wchar_t, std::char_traits<wchar_t>, test_allocator<wchar_t> > wstr;
@@ -99,4 +99,6 @@ int main()
         assert(r == out + 34);
         assert(std::wstring(out) == L"match: cdefghi, m[1]: efg, m[2]: e");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.form/form3.pass.cpp b/libcxx/test/std/re/re.results/re.results.form/form3.pass.cpp
index ca1a30732bd..62a735ca600 100644
--- a/libcxx/test/std/re/re.results/re.results.form/form3.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.form/form3.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::basic_string<char, std::char_traits<char>, test_allocator<char> > nstr;
     typedef std::basic_string<wchar_t, std::char_traits<wchar_t>, test_allocator<wchar_t> > wstr;
@@ -82,4 +82,6 @@ int main()
         wstr out = m.format(fmt, std::regex_constants::format_sed);
         assert(out == L"match: cdefghi, m[1]: efg, m[2]: e");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.form/form4.pass.cpp b/libcxx/test/std/re/re.results/re.results.form/form4.pass.cpp
index d46d6248d74..658e788b639 100644
--- a/libcxx/test/std/re/re.results/re.results.form/form4.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.form/form4.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::match_results<const char*> m;
@@ -77,4 +77,6 @@ int main()
         std::wstring out = m.format(fmt, std::regex_constants::format_sed);
         assert(out == L"match: cdefghi, m[1]: efg, m[2]: e");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.nonmember/equal.pass.cpp b/libcxx/test/std/re/re.results/re.results.nonmember/equal.pass.cpp
index e0b53609af6..3723ad4740f 100644
--- a/libcxx/test/std/re/re.results/re.results.nonmember/equal.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.nonmember/equal.pass.cpp
@@ -40,7 +40,9 @@ test()
     assert(m1 == m2);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.size/empty.fail.cpp b/libcxx/test/std/re/re.results/re.results.size/empty.fail.cpp
index 7a92dd88ef7..e17c7742465 100644
--- a/libcxx/test/std/re/re.results/re.results.size/empty.fail.cpp
+++ b/libcxx/test/std/re/re.results/re.results.size/empty.fail.cpp
@@ -19,8 +19,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::match_results<const char*> c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.size/empty.pass.cpp b/libcxx/test/std/re/re.results/re.results.size/empty.pass.cpp
index 4644a8afb64..7eaed34ac6a 100644
--- a/libcxx/test/std/re/re.results/re.results.size/empty.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.size/empty.pass.cpp
@@ -30,7 +30,9 @@ test()
     assert(m.size() == 3);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.size/max_size.pass.cpp b/libcxx/test/std/re/re.results/re.results.size/max_size.pass.cpp
index 5293f45f78e..184933d135c 100644
--- a/libcxx/test/std/re/re.results/re.results.size/max_size.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.size/max_size.pass.cpp
@@ -24,8 +24,10 @@ test()
     assert(m.max_size() > 0);
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.state/ready.pass.cpp b/libcxx/test/std/re/re.results/re.results.state/ready.pass.cpp
index daa1bf33730..476a66fdfba 100644
--- a/libcxx/test/std/re/re.results/re.results.state/ready.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.state/ready.pass.cpp
@@ -36,8 +36,10 @@ test2()
     assert(m.ready() == true);
 }
 
-int main()
+int main(int, char**)
 {
     test1();
     test2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.swap/member_swap.pass.cpp b/libcxx/test/std/re/re.results/re.results.swap/member_swap.pass.cpp
index 9cb6ae4417b..967fe11c5ac 100644
--- a/libcxx/test/std/re/re.results/re.results.swap/member_swap.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.swap/member_swap.pass.cpp
@@ -33,7 +33,9 @@ test()
     assert(m2 == m1_save);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/re.results.swap/non_member_swap.pass.cpp b/libcxx/test/std/re/re.results/re.results.swap/non_member_swap.pass.cpp
index 21724fc4933..59ba59f3d64 100644
--- a/libcxx/test/std/re/re.results/re.results.swap/non_member_swap.pass.cpp
+++ b/libcxx/test/std/re/re.results/re.results.swap/non_member_swap.pass.cpp
@@ -35,7 +35,9 @@ test()
     assert(m2 == m1_save);
 }
 
-int main()
+int main(int, char**)
 {
     test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.results/types.pass.cpp b/libcxx/test/std/re/re.results/types.pass.cpp
index 3f5a31d0d9d..0fd8220843b 100644
--- a/libcxx/test/std/re/re.results/types.pass.cpp
+++ b/libcxx/test/std/re/re.results/types.pass.cpp
@@ -44,8 +44,10 @@ test()
     static_assert((std::is_same<typename MR::string_type, std::basic_string<CharT> >::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<char>();
     test<wchar_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/compare_string_type.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/compare_string_type.pass.cpp
index 050680ae7f2..6b57a193aed 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/compare_string_type.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/compare_string_type.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -44,4 +44,6 @@ int main()
         assert(sm.compare(string()) > 0);
         assert(sm.compare(string(L"123")) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/compare_sub_match.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/compare_sub_match.pass.cpp
index 6e7d34d78e5..6d0976bbf21 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/compare_sub_match.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/compare_sub_match.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -50,4 +50,6 @@ int main()
         sm2.matched = true;
         assert(sm.compare(sm2) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/compare_value_type_ptr.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/compare_value_type_ptr.pass.cpp
index 672d4aa32c1..42e6ab94a17 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/compare_value_type_ptr.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/compare_value_type_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -42,4 +42,6 @@ int main()
         assert(sm.compare(L"") > 0);
         assert(sm.compare(L"123") == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/default.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/default.pass.cpp
index a2473552ea0..c34591f2284 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/default.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/default.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -30,4 +30,6 @@ int main()
         SM sm;
         assert(sm.matched == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/length.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/length.pass.cpp
index 459a8fe912d..5246eb3511b 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/length.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/length.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -40,4 +40,6 @@ int main()
         sm.matched = true;
         assert(sm.length() == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/operator_string.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/operator_string.pass.cpp
index 47659e59cce..051ecc3e873 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/operator_string.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/operator_string.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -44,4 +44,6 @@ int main()
         str = sm;
         assert(str == std::wstring(L"123"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.members/str.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.members/str.pass.cpp
index c09783b80cf..af39ee9c30f 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.members/str.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.members/str.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef char CharT;
@@ -44,4 +44,6 @@ int main()
         str = sm.str();
         assert(str == std::wstring(L"123"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.op/compare.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.op/compare.pass.cpp
index ad65ec54d30..e332a837983 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.op/compare.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.op/compare.pass.cpp
@@ -276,7 +276,7 @@ test(const std::basic_string<CharT>& x, const std::basic_string<CharT>& y, bool
     assert((sm1 >= y[0]) == (x >= string(1, y[0])));
 }
 
-int main()
+int main(int, char**)
 {
     test(std::string("123"), std::string("123"));
     test(std::string("1234"), std::string("123"));
@@ -284,4 +284,6 @@ int main()
     test(std::wstring(L"1234"), std::wstring(L"123"));
     test(std::string("123\000" "56", 6), std::string("123\000" "56", 6), false);
     test(std::wstring(L"123\000" L"56", 6), std::wstring(L"123\000" L"56", 6), false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/re.submatch.op/stream.pass.cpp b/libcxx/test/std/re/re.submatch/re.submatch.op/stream.pass.cpp
index 63c7d815c3c..070266d9e58 100644
--- a/libcxx/test/std/re/re.submatch/re.submatch.op/stream.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/re.submatch.op/stream.pass.cpp
@@ -35,8 +35,10 @@ test(const std::basic_string<CharT>& s)
     assert(os.str() == s);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::string("123"));
     test(std::wstring(L"123"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.submatch/types.pass.cpp b/libcxx/test/std/re/re.submatch/types.pass.cpp
index 8141a5302fb..831eec1da05 100644
--- a/libcxx/test/std/re/re.submatch/types.pass.cpp
+++ b/libcxx/test/std/re/re.submatch/types.pass.cpp
@@ -27,7 +27,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::sub_match<char*> SM;
@@ -61,4 +61,6 @@ int main()
         static_assert((std::is_same<std::ssub_match, std::sub_match<std::string::const_iterator> >::value), "");
         static_assert((std::is_same<std::wssub_match, std::sub_match<std::wstring::const_iterator> >::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/cmatch.pass.cpp b/libcxx/test/std/re/re.syn/cmatch.pass.cpp
index 1e7149bb7da..7b85a69a2ff 100644
--- a/libcxx/test/std/re/re.syn/cmatch.pass.cpp
+++ b/libcxx/test/std/re/re.syn/cmatch.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::match_results<const char*>, std::cmatch>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/cregex_iterator.pass.cpp b/libcxx/test/std/re/re.syn/cregex_iterator.pass.cpp
index 15c7ea8cfa4..29fdadeb669 100644
--- a/libcxx/test/std/re/re.syn/cregex_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/cregex_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_iterator<const char*>, std::cregex_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/cregex_token_iterator.pass.cpp b/libcxx/test/std/re/re.syn/cregex_token_iterator.pass.cpp
index a5b1bc58340..7ca531dfe63 100644
--- a/libcxx/test/std/re/re.syn/cregex_token_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/cregex_token_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_token_iterator<const char*>, std::cregex_token_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/csub_match.pass.cpp b/libcxx/test/std/re/re.syn/csub_match.pass.cpp
index 7c3d644fd11..2ace0b983bf 100644
--- a/libcxx/test/std/re/re.syn/csub_match.pass.cpp
+++ b/libcxx/test/std/re/re.syn/csub_match.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::sub_match<const char*>, std::csub_match>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/regex.pass.cpp b/libcxx/test/std/re/re.syn/regex.pass.cpp
index 1fe91ec349b..0b4c07b6ff1 100644
--- a/libcxx/test/std/re/re.syn/regex.pass.cpp
+++ b/libcxx/test/std/re/re.syn/regex.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::basic_regex<char>, std::regex>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/smatch.pass.cpp b/libcxx/test/std/re/re.syn/smatch.pass.cpp
index bee9f9f0d63..01fa1e95552 100644
--- a/libcxx/test/std/re/re.syn/smatch.pass.cpp
+++ b/libcxx/test/std/re/re.syn/smatch.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::match_results<std::string::const_iterator>, std::smatch>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/sregex_iterator.pass.cpp b/libcxx/test/std/re/re.syn/sregex_iterator.pass.cpp
index a691cc799a7..1ae462c6b77 100644
--- a/libcxx/test/std/re/re.syn/sregex_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/sregex_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_iterator<std::string::const_iterator>, std::sregex_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/sregex_token_iterator.pass.cpp b/libcxx/test/std/re/re.syn/sregex_token_iterator.pass.cpp
index 6d148280d73..4b67b66f291 100644
--- a/libcxx/test/std/re/re.syn/sregex_token_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/sregex_token_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_token_iterator<std::string::const_iterator>, std::sregex_token_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/ssub_match.pass.cpp b/libcxx/test/std/re/re.syn/ssub_match.pass.cpp
index 0730d667ef1..fe331296849 100644
--- a/libcxx/test/std/re/re.syn/ssub_match.pass.cpp
+++ b/libcxx/test/std/re/re.syn/ssub_match.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::sub_match<std::string::const_iterator>, std::ssub_match>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wcmatch.pass.cpp b/libcxx/test/std/re/re.syn/wcmatch.pass.cpp
index 4c9b7e1f272..f373e57ac46 100644
--- a/libcxx/test/std/re/re.syn/wcmatch.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wcmatch.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::match_results<const wchar_t*>, std::wcmatch>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wcregex_iterator.pass.cpp b/libcxx/test/std/re/re.syn/wcregex_iterator.pass.cpp
index c81aa78c157..3425c98fe8c 100644
--- a/libcxx/test/std/re/re.syn/wcregex_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wcregex_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_iterator<const wchar_t*>, std::wcregex_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wcregex_token_iterator.pass.cpp b/libcxx/test/std/re/re.syn/wcregex_token_iterator.pass.cpp
index 9d407103aab..217653837e0 100644
--- a/libcxx/test/std/re/re.syn/wcregex_token_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wcregex_token_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_token_iterator<const wchar_t*>, std::wcregex_token_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wcsub_match.pass.cpp b/libcxx/test/std/re/re.syn/wcsub_match.pass.cpp
index 7f18b272f99..86a2103b8bd 100644
--- a/libcxx/test/std/re/re.syn/wcsub_match.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wcsub_match.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::sub_match<const wchar_t*>, std::wcsub_match>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wregex.pass.cpp b/libcxx/test/std/re/re.syn/wregex.pass.cpp
index 9622b89d6d7..5be6f6fb59e 100644
--- a/libcxx/test/std/re/re.syn/wregex.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wregex.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::basic_regex<wchar_t>, std::wregex>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wsmatch.pass.cpp b/libcxx/test/std/re/re.syn/wsmatch.pass.cpp
index 98bcbdc4dcf..760057e6a74 100644
--- a/libcxx/test/std/re/re.syn/wsmatch.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wsmatch.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::match_results<std::wstring::const_iterator>, std::wsmatch>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wsregex_iterator.pass.cpp b/libcxx/test/std/re/re.syn/wsregex_iterator.pass.cpp
index 1f733d9050d..b1d7edf8770 100644
--- a/libcxx/test/std/re/re.syn/wsregex_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wsregex_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_iterator<std::wstring::const_iterator>, std::wsregex_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wsregex_token_iterator.pass.cpp b/libcxx/test/std/re/re.syn/wsregex_token_iterator.pass.cpp
index b65e4134589..58454a59e93 100644
--- a/libcxx/test/std/re/re.syn/wsregex_token_iterator.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wsregex_token_iterator.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_token_iterator<std::wstring::const_iterator>, std::wsregex_token_iterator>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.syn/wssub_match.pass.cpp b/libcxx/test/std/re/re.syn/wssub_match.pass.cpp
index 8f82b34d295..7ca6dc7734c 100644
--- a/libcxx/test/std/re/re.syn/wssub_match.pass.cpp
+++ b/libcxx/test/std/re/re.syn/wssub_match.pass.cpp
@@ -14,7 +14,9 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::sub_match<std::wstring::const_iterator>, std::wssub_match>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/default.pass.cpp b/libcxx/test/std/re/re.traits/default.pass.cpp
index b49cc864701..459f044e037 100644
--- a/libcxx/test/std/re/re.traits/default.pass.cpp
+++ b/libcxx/test/std/re/re.traits/default.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t1;
@@ -36,4 +36,6 @@ int main()
         std::regex_traits<wchar_t> t2;
         assert(t2.getloc().name() == LOCALE_en_US_UTF_8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/getloc.pass.cpp b/libcxx/test/std/re/re.traits/getloc.pass.cpp
index 82e804dc681..dbc35dec39a 100644
--- a/libcxx/test/std/re/re.traits/getloc.pass.cpp
+++ b/libcxx/test/std/re/re.traits/getloc.pass.cpp
@@ -20,7 +20,7 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t1;
@@ -35,4 +35,6 @@ int main()
         std::regex_traits<wchar_t> t2;
         assert(t2.getloc().name() == LOCALE_en_US_UTF_8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/imbue.pass.cpp b/libcxx/test/std/re/re.traits/imbue.pass.cpp
index d2343f2712e..0200ce01e3c 100644
--- a/libcxx/test/std/re/re.traits/imbue.pass.cpp
+++ b/libcxx/test/std/re/re.traits/imbue.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -29,4 +29,6 @@ int main()
         assert(loc.name() == "C");
         assert(t.getloc().name() == LOCALE_en_US_UTF_8);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/isctype.pass.cpp b/libcxx/test/std/re/re.traits/isctype.pass.cpp
index a2f9e2b93d8..1eed193ae00 100644
--- a/libcxx/test/std/re/re.traits/isctype.pass.cpp
+++ b/libcxx/test/std/re/re.traits/isctype.pass.cpp
@@ -20,7 +20,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -280,4 +280,6 @@ int main()
         assert(!t.isctype(L'-', t.lookup_classname(s.begin(), s.end())));
         assert(!t.isctype(L'@', t.lookup_classname(s.begin(), s.end())));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/length.pass.cpp b/libcxx/test/std/re/re.traits/length.pass.cpp
index 822f781abc4..dce6284bc19 100644
--- a/libcxx/test/std/re/re.traits/length.pass.cpp
+++ b/libcxx/test/std/re/re.traits/length.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::regex_traits<char>::length("") == 0);
     assert(std::regex_traits<char>::length("1") == 1);
@@ -28,4 +28,6 @@ int main()
     assert(std::regex_traits<wchar_t>::length(L"1") == 1);
     assert(std::regex_traits<wchar_t>::length(L"12") == 2);
     assert(std::regex_traits<wchar_t>::length(L"123") == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/lookup_classname.pass.cpp b/libcxx/test/std/re/re.traits/lookup_classname.pass.cpp
index 74207a0191b..38bafa67ebf 100644
--- a/libcxx/test/std/re/re.traits/lookup_classname.pass.cpp
+++ b/libcxx/test/std/re/re.traits/lookup_classname.pass.cpp
@@ -53,7 +53,7 @@ test_w(const char_type* A,
       assert(!matches_underscore && "should not match underscore");
 }
 
-int main()
+int main(int, char**)
 {
 //  if __regex_word is not distinct from all the classes, bad things happen
 //  See https://bugs.llvm.org/show_bug.cgi?id=26476 for an example.
@@ -243,4 +243,6 @@ int main()
     test(L"dig", std::ctype_base::mask());
     test(L"", std::ctype_base::mask());
     test(L"digits", std::ctype_base::mask());
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp b/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp
index 3e1fd860a0b..aeb7c50bb81 100644
--- a/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp
+++ b/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp
@@ -39,7 +39,7 @@ test(const char_type* A, const std::basic_string<char_type>& expected)
     assert(t.lookup_collatename(F(A), F(A + t.length(A))) == expected);
 }
 
-int main()
+int main(int, char**)
 {
     test("NUL", std::string("\x00", 1));
     test("alert", std::string("\x07"));
@@ -192,4 +192,6 @@ int main()
     std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
     test(L"ch", std::wstring(L"ch"));
     std::locale::global(std::locale("C"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/transform.pass.cpp b/libcxx/test/std/re/re.traits/transform.pass.cpp
index 75a6c40c76c..0125d419eae 100644
--- a/libcxx/test/std/re/re.traits/transform.pass.cpp
+++ b/libcxx/test/std/re/re.traits/transform.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_iterators.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -45,4 +45,6 @@ int main()
         t.imbue(std::locale(LOCALE_cs_CZ_ISO8859_2));
         assert(t.transform(F(a), F(a+1)) < t.transform(F(B), F(B+1)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/transform_primary.pass.cpp b/libcxx/test/std/re/re.traits/transform_primary.pass.cpp
index b2dab418a6e..e24125e0691 100644
--- a/libcxx/test/std/re/re.traits/transform_primary.pass.cpp
+++ b/libcxx/test/std/re/re.traits/transform_primary.pass.cpp
@@ -27,7 +27,7 @@
 #include "test_iterators.h"
 #include "platform_support.h" // locale name macros
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -51,4 +51,6 @@ int main()
         assert(t.transform_primary(F(A), F(A+1)) ==
                t.transform_primary(F(Aacute), F(Aacute+1)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/translate.pass.cpp b/libcxx/test/std/re/re.traits/translate.pass.cpp
index 96c77f97c8a..e56af4df37c 100644
--- a/libcxx/test/std/re/re.traits/translate.pass.cpp
+++ b/libcxx/test/std/re/re.traits/translate.pass.cpp
@@ -17,7 +17,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -31,4 +31,6 @@ int main()
         assert(t.translate(L'B') == L'B');
         assert(t.translate(L'c') == L'c');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/translate_nocase.pass.cpp b/libcxx/test/std/re/re.traits/translate_nocase.pass.cpp
index 893c0cd284e..6e9f01d1626 100644
--- a/libcxx/test/std/re/re.traits/translate_nocase.pass.cpp
+++ b/libcxx/test/std/re/re.traits/translate_nocase.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "platform_support.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -61,4 +61,6 @@ int main()
         assert(t.translate_nocase(L'\xDA') == L'\xFA');
         assert(t.translate_nocase(L'\xFA') == L'\xFA');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/types.pass.cpp b/libcxx/test/std/re/re.traits/types.pass.cpp
index 0d7a2f29b72..c3a8770f01d 100644
--- a/libcxx/test/std/re/re.traits/types.pass.cpp
+++ b/libcxx/test/std/re/re.traits/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::regex_traits<char>::char_type, char>::value), "");
     static_assert((std::is_same<std::regex_traits<char>::string_type, std::string>::value), "");
@@ -29,4 +29,6 @@ int main()
     static_assert((std::is_same<std::regex_traits<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::regex_traits<wchar_t>::string_type, std::wstring>::value), "");
     static_assert((std::is_same<std::regex_traits<wchar_t>::locale_type, std::locale>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/re/re.traits/value.pass.cpp b/libcxx/test/std/re/re.traits/value.pass.cpp
index 89bf9c3527c..b7ca1fb7c07 100644
--- a/libcxx/test/std/re/re.traits/value.pass.cpp
+++ b/libcxx/test/std/re/re.traits/value.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::regex_traits<char> t;
@@ -122,4 +122,6 @@ int main()
             assert(t.value(c, 16) == -1);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.hash/enabled_hashes.pass.cpp b/libcxx/test/std/strings/basic.string.hash/enabled_hashes.pass.cpp
index 10504c50151..0fecb1bb081 100644
--- a/libcxx/test/std/strings/basic.string.hash/enabled_hashes.pass.cpp
+++ b/libcxx/test/std/strings/basic.string.hash/enabled_hashes.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::string>();
@@ -30,4 +30,6 @@ int main() {
     test_hash_enabled_for_type<std::u32string>();
 #endif
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.hash/strings.pass.cpp b/libcxx/test/std/strings/basic.string.hash/strings.pass.cpp
index ea97e64f203..c2a2ef95647 100644
--- a/libcxx/test/std/strings/basic.string.hash/strings.pass.cpp
+++ b/libcxx/test/std/strings/basic.string.hash/strings.pass.cpp
@@ -40,7 +40,7 @@ test()
     assert(h(s1) != h(s2));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::string>();
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -51,4 +51,6 @@ int main()
     test<std::u32string>();
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
     test<std::wstring>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.literals/literal.pass.cpp b/libcxx/test/std/strings/basic.string.literals/literal.pass.cpp
index eed5c9420ac..a51d0d9ac8c 100644
--- a/libcxx/test/std/strings/basic.string.literals/literal.pass.cpp
+++ b/libcxx/test/std/strings/basic.string.literals/literal.pass.cpp
@@ -21,7 +21,7 @@
 #endif
 
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::string_literals;
 
@@ -54,4 +54,6 @@ int main()
     Lfoo  =  L"ABC"s;     assert( Lfoo ==  L"ABC");   assert( Lfoo == std::wstring  ( L"ABC"));
     ufoo  =  u"ABC"s;     assert( ufoo ==  u"ABC");   assert( ufoo == std::u16string( u"ABC"));
     Ufoo  =  U"ABC"s;     assert( Ufoo ==  U"ABC");   assert( Ufoo == std::u32string( U"ABC"));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.literals/literal1.fail.cpp b/libcxx/test/std/strings/basic.string.literals/literal1.fail.cpp
index 129d2844777..be4604059fe 100644
--- a/libcxx/test/std/strings/basic.string.literals/literal1.fail.cpp
+++ b/libcxx/test/std/strings/basic.string.literals/literal1.fail.cpp
@@ -12,9 +12,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using std::string;
 
     string foo  =   ""s;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.literals/literal1.pass.cpp b/libcxx/test/std/strings/basic.string.literals/literal1.pass.cpp
index 5134ec79aaa..92777c4f428 100644
--- a/libcxx/test/std/strings/basic.string.literals/literal1.pass.cpp
+++ b/libcxx/test/std/strings/basic.string.literals/literal1.pass.cpp
@@ -12,9 +12,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals;
 
     std::string foo  =   ""s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.literals/literal2.fail.cpp b/libcxx/test/std/strings/basic.string.literals/literal2.fail.cpp
index 3ebbfa24c13..54a0a9e405b 100644
--- a/libcxx/test/std/strings/basic.string.literals/literal2.fail.cpp
+++ b/libcxx/test/std/strings/basic.string.literals/literal2.fail.cpp
@@ -12,7 +12,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::string foo  =   ""s;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.literals/literal2.pass.cpp b/libcxx/test/std/strings/basic.string.literals/literal2.pass.cpp
index ac41ce94c9b..6f73ae9a103 100644
--- a/libcxx/test/std/strings/basic.string.literals/literal2.pass.cpp
+++ b/libcxx/test/std/strings/basic.string.literals/literal2.pass.cpp
@@ -12,9 +12,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::string_literals;
 
     std::string foo  =   ""s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string.literals/literal3.pass.cpp b/libcxx/test/std/strings/basic.string.literals/literal3.pass.cpp
index c5ca6708add..b7a8d553687 100644
--- a/libcxx/test/std/strings/basic.string.literals/literal3.pass.cpp
+++ b/libcxx/test/std/strings/basic.string.literals/literal3.pass.cpp
@@ -12,9 +12,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std;
 
     string foo  =   ""s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/allocator_mismatch.fail.cpp b/libcxx/test/std/strings/basic.string/allocator_mismatch.fail.cpp
index ae63acfcec1..1d016991f0c 100644
--- a/libcxx/test/std/strings/basic.string/allocator_mismatch.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/allocator_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <string>
 
-int main()
+int main(int, char**)
 {
     std::basic_string<char, std::char_traits<char>, std::allocator<int> > s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/char.bad.fail.cpp b/libcxx/test/std/strings/basic.string/char.bad.fail.cpp
index d78cb6aad98..bace91c3222 100644
--- a/libcxx/test/std/strings/basic.string/char.bad.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/char.bad.fail.cpp
@@ -26,7 +26,7 @@ private:
     int two;
 };
 
-int main()
+int main(int, char**)
 {
     {
 //  array
@@ -49,4 +49,6 @@ int main()
     std::basic_string<NotStandardLayout, test_traits<NotStandardLayout> > s;
 //  expected-error-re@string:* {{static_assert failed{{.*}} "Character type of basic_string must be standard-layout"}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.access/at.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/at.pass.cpp
index 6515e272721..514d1a894ce 100644
--- a/libcxx/test/std/strings/basic.string/string.access/at.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/at.pass.cpp
@@ -54,7 +54,7 @@ test(S s, typename S::size_type pos)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -74,4 +74,6 @@ int main()
     test(S("123"), 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.access/back.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/back.pass.cpp
index b4108010ac3..3831da0845c 100644
--- a/libcxx/test/std/strings/basic.string/string.access/back.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/back.pass.cpp
@@ -31,7 +31,7 @@ test(S s)
     assert(s.back() == typename S::value_type('z'));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -52,4 +52,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.access/db_back.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/db_back.pass.cpp
index 5034bfa11a9..e1cf707a6f0 100644
--- a/libcxx/test/std/strings/basic.string/string.access/db_back.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/db_back.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.access/db_cback.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/db_cback.pass.cpp
index ddffb6cd787..e3e6db525e4 100644
--- a/libcxx/test/std/strings/basic.string/string.access/db_cback.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/db_cback.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -42,8 +42,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.access/db_cfront.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/db_cfront.pass.cpp
index e171883dc36..c9b2ba7c88e 100644
--- a/libcxx/test/std/strings/basic.string/string.access/db_cfront.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/db_cfront.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -42,8 +42,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.access/db_cindex.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/db_cindex.pass.cpp
index 770ab333c8b..c7b430efc98 100644
--- a/libcxx/test/std/strings/basic.string/string.access/db_cindex.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/db_cindex.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -44,8 +44,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.access/db_front.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/db_front.pass.cpp
index 7f2db649a12..73db2240510 100644
--- a/libcxx/test/std/strings/basic.string/string.access/db_front.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/db_front.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.access/db_index.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/db_index.pass.cpp
index 40318e3988f..d3f2e8d28d0 100644
--- a/libcxx/test/std/strings/basic.string/string.access/db_index.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/db_index.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -44,8 +44,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.access/front.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/front.pass.cpp
index 5eee328feca..d51a12f0a77 100644
--- a/libcxx/test/std/strings/basic.string/string.access/front.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/front.pass.cpp
@@ -31,7 +31,7 @@ test(S s)
     assert(s.front() == typename S::value_type('z'));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -52,4 +52,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.access/index.pass.cpp b/libcxx/test/std/strings/basic.string/string.access/index.pass.cpp
index d529567c6fb..3a1224ca301 100644
--- a/libcxx/test/std/strings/basic.string/string.access/index.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.access/index.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -59,4 +59,6 @@ int main()
         assert(false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/capacity.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/capacity.pass.cpp
index 9f09dea1d3e..02187c5193a 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/capacity.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/capacity.pass.cpp
@@ -40,7 +40,7 @@ test(S s)
     S::allocator_type::throw_after = INT_MAX;
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::basic_string<char, std::char_traits<char>, test_allocator<char> > S;
@@ -60,4 +60,6 @@ int main()
     assert(s.capacity() > 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/clear.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/clear.pass.cpp
index 4f75e013401..914842bb7a6 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/clear.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/clear.pass.cpp
@@ -23,7 +23,7 @@ test(S s)
     assert(s.size() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -53,4 +53,6 @@ int main()
     test(s);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/empty.fail.cpp b/libcxx/test/std/strings/basic.string/string.capacity/empty.fail.cpp
index 2359dea942d..1bfa388b7b9 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/empty.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::string c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/empty.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/empty.pass.cpp
index 56d925d571c..47827db7f75 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/empty.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/empty.pass.cpp
@@ -24,7 +24,7 @@ test(const S& s)
     assert(s.empty() == (s.size() == 0));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -40,4 +40,6 @@ int main()
     test(S("12345678901234567890123456789012345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/length.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/length.pass.cpp
index 617d81a9205..b61ec488e27 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/length.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/length.pass.cpp
@@ -22,7 +22,7 @@ test(const S& s)
     assert(s.length() == s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -38,4 +38,6 @@ int main()
     test(S("12345678901234567890123456789012345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/max_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/max_size.pass.cpp
index 68017f45349..8f8c9a3fb42 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/max_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/max_size.pass.cpp
@@ -54,7 +54,7 @@ test(const S& s)
     test2(s);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -70,4 +70,6 @@ int main()
     test(S("12345678901234567890123456789012345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/over_max_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/over_max_size.pass.cpp
index 414b6742495..9832df536c9 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/over_max_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/over_max_size.pass.cpp
@@ -35,7 +35,7 @@ test(const S& s)
     assert ( false );
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -51,4 +51,6 @@ int main()
     test(S("12345678901234567890123456789012345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp
index 33699a79932..f49125cec98 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp
@@ -65,7 +65,7 @@ test(S s, typename S::size_type res_arg)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -131,4 +131,6 @@ int main()
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/resize_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/resize_size.pass.cpp
index ad37dc30a1e..8b545939e3d 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/resize_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/resize_size.pass.cpp
@@ -43,7 +43,7 @@ test(S s, typename S::size_type n, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -85,4 +85,6 @@ int main()
     test(S(), S::npos, S("not going to happen"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/resize_size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/resize_size_char.pass.cpp
index b9005341456..b5e5aff8424 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/resize_size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/resize_size_char.pass.cpp
@@ -43,7 +43,7 @@ test(S s, typename S::size_type n, typename S::value_type c, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -85,4 +85,6 @@ int main()
     test(S(), S::npos, 'a', S("not going to happen"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp
index ee91ac1676b..2c6ce0df6f9 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp
@@ -29,7 +29,7 @@ test(S s)
     assert(s.capacity() >= s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -59,4 +59,6 @@ int main()
     test(s);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/size.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/size.pass.cpp
index 16b236eebb8..f3f89a5a6d8 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/size.pass.cpp
@@ -22,7 +22,7 @@ test(const S& s, typename S::size_type c)
     assert(s.size() == c);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -38,4 +38,6 @@ int main()
     test(S("12345678901234567890123456789012345678901234567890"), 50);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/T_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/T_size_size.pass.cpp
index 4f8158ea56d..38725979f9d 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/T_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/T_size_size.pass.cpp
@@ -91,7 +91,7 @@ test(SV sv, std::size_t pos, std::size_t n, const typename S::allocator_type& a)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -183,4 +183,6 @@ int main()
     S s7(s.data(), 2);     // calls ctor(const char *, len)
     assert(s7 == "AB");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp
index a2518a184c0..765f61eafb8 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp
@@ -85,11 +85,13 @@ test2()
 
 #endif
 
-int main()
+int main(int, char**)
 {
     test<std::basic_string<char, std::char_traits<char>, test_allocator<char> > >();
 #if TEST_STD_VER >= 11
     test2<std::basic_string<char, std::char_traits<char>, min_allocator<char> > >();
     test2<std::basic_string<char, std::char_traits<char>, explicit_allocator<char> > >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/brace_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/brace_assignment.pass.cpp
index 44db3c14059..5e77e46b2e4 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/brace_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/brace_assignment.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   // Test that assignment from {} and {ptr, len} are allowed and are not
   // ambiguous.
@@ -32,4 +32,6 @@ int main()
     s = {"abc", 2};
     assert(s == "ab");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/char_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/char_assignment.pass.cpp
index e3976cffa94..53f676e3bb3 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/char_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/char_assignment.pass.cpp
@@ -28,7 +28,7 @@ test(S s1, typename S::value_type s2)
     assert(s1.capacity() >= s1.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -46,4 +46,6 @@ int main()
     test(S("1234567890123456789012345678901234567890123456789012345678901234567890"), 'a');
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/copy.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/copy.pass.cpp
index f2cfa8a0e37..0024f2defac 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/copy.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/copy.pass.cpp
@@ -28,7 +28,7 @@ test(S s1)
     assert(s2.get_allocator() == s1.get_allocator());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -46,4 +46,6 @@ int main()
     test(S("1234567890123456789012345678901234567890123456789012345678901234567890", A()));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp
index 57a17e8abb9..a635f017e80 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp
@@ -87,7 +87,7 @@ test(S s1, const typename S::allocator_type& a)
     assert(s2.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -127,4 +127,6 @@ int main()
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/copy_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/copy_assignment.pass.cpp
index a3c1389dafe..8b3b7ac04c8 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/copy_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/copy_assignment.pass.cpp
@@ -27,7 +27,7 @@ test(S s1, const S& s2)
     assert(s1.capacity() >= s1.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -76,4 +76,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/default_noexcept.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/default_noexcept.pass.cpp
index 1ab00b60e11..301876b2c3b 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/default_noexcept.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/default_noexcept.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::string C;
@@ -35,4 +35,6 @@ int main()
         typedef std::basic_string<char, std::char_traits<char>, limited_allocator<char, 10>> C;
         static_assert(!std::is_nothrow_default_constructible<C>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/dtor_noexcept.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/dtor_noexcept.pass.cpp
index 5b57fe3cadc..d1372d29643 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/dtor_noexcept.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/dtor_noexcept.pass.cpp
@@ -32,7 +32,7 @@ struct throwing_alloc
 std::string s;
 std::wstring ws;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::string C;
@@ -48,4 +48,6 @@ int main()
         static_assert(!std::is_nothrow_destructible<C>::value, "");
     }
 #endif // _LIBCPP_VERSION
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/implicit_deduction_guides.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/implicit_deduction_guides.pass.cpp
index 7eb364e6239..9e31d3e6f9e 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/implicit_deduction_guides.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/implicit_deduction_guides.pass.cpp
@@ -46,7 +46,7 @@ using BStr = std::basic_string<T, std::char_traits<T>, Alloc>;
 // (13) basic_string(initializer_list<CharT>, A const& = A())
 // (14) basic_string(BSV, A const& = A())
 // (15) basic_string(const T&, size_type, size_type, A const& = A())
-int main()
+int main(int, char**)
 {
   using TestSizeT = test_allocator<char>::size_type;
   { // Testing (1)
@@ -313,4 +313,6 @@ int main()
     ASSERT_SAME_TYPE(decltype(w), ExpectW);
     assert(w == L"cd");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/initializer_list.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/initializer_list.pass.cpp
index 3a8914cd3d8..a106203d49c 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s = {'a', 'b', 'c'};
@@ -40,4 +40,6 @@ int main()
         s = {L'a', L'b', L'c'};
         assert(s == L"abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/initializer_list_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/initializer_list_assignment.pass.cpp
index 6a512f27413..dcb9bb911b4 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/initializer_list_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/initializer_list_assignment.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s;
@@ -30,4 +30,6 @@ int main()
         s = {'a', 'b', 'c'};
         assert(s == "abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
index 6966e6e5d24..042018cb532 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
@@ -56,7 +56,7 @@ test(It first, It last, const A& a)
     assert(s2.capacity() >= s2.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -116,4 +116,6 @@ int main()
     test(input_iterator<const char*>(s), input_iterator<const char*>(s+50), A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.fail.cpp b/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.fail.cpp
index f87aac5f0e7..57fd550ac47 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.fail.cpp
@@ -35,7 +35,7 @@ class NotAnItertor {};
 template <typename T>
 struct NotAnAllocator { typedef T value_type; };
 
-int main()
+int main(int, char**)
 {
     { // Not an iterator at all
     std::basic_string s1{NotAnItertor{}, NotAnItertor{}, std::allocator<char>{}}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
@@ -52,4 +52,6 @@ int main()
     std::basic_string s1{s, s+10, NotAnAllocator<wchar_t>{}}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.pass.cpp
index dac9ee33277..44daab4fcdc 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/iter_alloc_deduction.pass.cpp
@@ -36,7 +36,7 @@
 #include "../input_iterator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "12345678901234";
@@ -89,4 +89,6 @@ int main()
     assert(s1.size() == 10);
     assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/move.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/move.pass.cpp
index 1c11368c7ea..729c8e80690 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/move.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/move.pass.cpp
@@ -32,7 +32,7 @@ test(S s0)
     assert(s2.get_allocator() == s1.get_allocator());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -48,4 +48,6 @@ int main()
     test(S("1", A()));
     test(S("1234567890123456789012345678901234567890123456789012345678901234567890", A()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/move_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/move_alloc.pass.cpp
index e426e2dc85d..63e349e71ce 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/move_alloc.pass.cpp
@@ -34,7 +34,7 @@ test(S s0, const typename S::allocator_type& a)
 }
 
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -74,4 +74,6 @@ int main()
     test(S("1"), A());
     test(S("1234567890123456789012345678901234567890123456789012345678901234567890"), A());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/move_assign_noexcept.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/move_assign_noexcept.pass.cpp
index 88bc1231071..2a00898c1de 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/move_assign_noexcept.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/move_assign_noexcept.pass.cpp
@@ -62,7 +62,7 @@ struct some_alloc3
     typedef std::false_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::string C;
@@ -93,4 +93,6 @@ int main()
         static_assert(!std::is_nothrow_move_assignable<C>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/move_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/move_assignment.pass.cpp
index b039e79554f..9684fe7380a 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/move_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/move_assignment.pass.cpp
@@ -32,7 +32,7 @@ test(S s1, S s2)
     assert(s1.capacity() >= s1.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -70,4 +70,6 @@ int main()
            "1234567890123456789012345678901234567890123456789012345678901234567890"),
          S("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/move_noexcept.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/move_noexcept.pass.cpp
index 374183f99ff..ee839cf261c 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/move_noexcept.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/move_noexcept.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::string C;
@@ -39,4 +39,6 @@ int main()
         static_assert( std::is_nothrow_move_constructible<C>::value, "");
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/pointer_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/pointer_alloc.pass.cpp
index b68c5228a4b..d67f1231fd3 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/pointer_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/pointer_alloc.pass.cpp
@@ -51,7 +51,7 @@ test(const charT* s, const A& a)
     assert(s2.capacity() >= s2.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -85,4 +85,6 @@ int main()
     test("123456798012345679801234567980123456798012345679801234567980", A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/pointer_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/pointer_assignment.pass.cpp
index 1216f3f18cd..4a885485bea 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/pointer_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/pointer_assignment.pass.cpp
@@ -29,7 +29,7 @@ test(S s1, const typename S::value_type* s2)
     assert(s1.capacity() >= s1.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -69,4 +69,6 @@ int main()
          "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/pointer_size_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/pointer_size_alloc.pass.cpp
index 96457135ed1..75ad883fcf1 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/pointer_size_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/pointer_size_alloc.pass.cpp
@@ -48,7 +48,7 @@ test(const charT* s, unsigned n, const A& a)
     assert(s2.capacity() >= s2.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -90,4 +90,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/size_char_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/size_char_alloc.pass.cpp
index 21ed485ef13..d509971910f 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/size_char_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/size_char_alloc.pass.cpp
@@ -80,7 +80,7 @@ test(Tp n, Tp c, const A& a)
     assert(s2.capacity() >= s2.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -120,4 +120,6 @@ int main()
     test(static_cast<char>(100), static_cast<char>(65), A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view.fail.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view.fail.cpp
index d7a054073d4..61d5b3db4e9 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view.fail.cpp
@@ -15,8 +15,10 @@
 
 void foo ( const string &s ) {}
 
-int main()
+int main(int, char**)
 {
     std::string_view sv = "ABCDE";
     foo(sv);    // requires implicit conversion from string_view to string
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view.pass.cpp
index f50d9e51981..b423c327dca 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view.pass.cpp
@@ -71,7 +71,7 @@ test(std::basic_string_view<charT> sv, const A& a)
   }
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -107,4 +107,6 @@ int main()
     test(SV("123456798012345679801234567980123456798012345679801234567980"), A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view_assignment.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view_assignment.pass.cpp
index 9a50f62a7ae..942d990ee50 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view_assignment.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view_assignment.pass.cpp
@@ -28,7 +28,7 @@ test(S s1, SV sv)
     assert(s1.capacity() >= s1.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -70,4 +70,6 @@ int main()
          SV("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.fail.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.fail.cpp
index 23e6668e69c..62ce16eca16 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.fail.cpp
@@ -31,10 +31,12 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
     std::string_view sv = "12345678901234";
     std::basic_string s1{sv, 23}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.pass.cpp
index ee731581fb6..b3adc41464f 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view_deduction.pass.cpp
@@ -38,7 +38,7 @@
 #include "../input_iterator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::string_view sv = "12345678901234";
@@ -103,4 +103,6 @@ int main()
     assert(s1.size() == sv.size());
     assert(s1.compare(0, s1.size(), sv.data(), s1.size()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.fail.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.fail.cpp
index ce4e695377f..cff605677de 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.fail.cpp
@@ -37,10 +37,12 @@
 #include <cassert>
 #include <cstddef>
 
-int main()
+int main(int, char**)
 {
     {
     std::string_view sv = "12345678901234";
     std::basic_string s1{sv, 0, 4, 23}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.pass.cpp
index daba3bd1204..983ab78e4ce 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/string_view_size_size_deduction.pass.cpp
@@ -42,7 +42,7 @@
 #include "../input_iterator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::string_view sv = "12345678901234";
@@ -107,4 +107,6 @@ int main()
     assert(s1.size() == 4);
     assert(s1.compare(0, s1.size(), sv.data(), s1.size()) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.cons/substr.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/substr.pass.cpp
index 05c53ac23db..44f29beec92 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/substr.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/substr.pass.cpp
@@ -140,7 +140,7 @@ void test2583()
 #endif
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -224,4 +224,6 @@ int main()
     test2583();
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.char.pass.cpp b/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.char.pass.cpp
index 7d1c26418be..e2afe04202c 100644
--- a/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.char.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -30,4 +30,6 @@ int main()
     assert ( s2.ends_with('e'));
     assert (!s2.ends_with('x'));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.ptr.pass.cpp b/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.ptr.pass.cpp
index 87b94042ffe..a4f8b1aa39c 100644
--- a/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.ptr.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.ptr.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -59,4 +59,6 @@ int main()
     assert (!sNot.ends_with("abcde"));
     assert ( sNot.ends_with("def"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.string_view.pass.cpp
index 3d75e23dac7..cbfffcfce98 100644
--- a/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ends_with/ends_with.string_view.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -68,4 +68,6 @@ int main()
     assert (!sNot.ends_with(sv5));
     assert ( sNot.ends_with(svNot));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/begin.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/begin.pass.cpp
index eedc9b991a2..fbae9fab7d2 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/begin.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/begin.pass.cpp
@@ -30,7 +30,7 @@ test(S s)
     assert(b == cb);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -44,4 +44,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/cbegin.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/cbegin.pass.cpp
index 720ba53e738..9886d56bbd9 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/cbegin.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/cbegin.pass.cpp
@@ -27,7 +27,7 @@ test(const S& s)
     assert(cb == s.begin());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -41,4 +41,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/cend.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/cend.pass.cpp
index 07d885aee88..1a3d30775f2 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/cend.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/cend.pass.cpp
@@ -23,7 +23,7 @@ test(const S& s)
     assert(ce == s.end());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -37,4 +37,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/crbegin.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/crbegin.pass.cpp
index 2b8837fd3d2..687c34368ae 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/crbegin.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/crbegin.pass.cpp
@@ -27,7 +27,7 @@ test(const S& s)
     assert(cb == s.rbegin());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -41,4 +41,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/crend.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/crend.pass.cpp
index c74b907fe7c..86aaad699d4 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/crend.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/crend.pass.cpp
@@ -23,7 +23,7 @@ test(const S& s)
     assert(ce == s.rend());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -37,4 +37,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_2.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_2.pass.cpp
index 074fa84bd8d..46963239476 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_2.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_2.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -44,8 +44,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_3.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_3.pass.cpp
index 9c63eeafe39..7dbbbbb4cba 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_3.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_3.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -44,8 +44,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_4.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_4.pass.cpp
index c01b22662b6..1a46f86c28d 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_4.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_4.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string C;
@@ -46,8 +46,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_5.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_5.pass.cpp
index a5a8d917b93..77caf1b814a 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_5.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_5.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string C;
@@ -50,8 +50,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_6.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_6.pass.cpp
index b4c7fb38006..126c3661c39 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_6.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_6.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string C;
@@ -48,8 +48,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_7.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_7.pass.cpp
index 6a262e0f397..f1083a43954 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_7.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_7.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string C;
@@ -48,8 +48,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_8.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_8.pass.cpp
index f3b5656f766..c69f8ca4b03 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_8.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/db_iterators_8.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string C;
@@ -44,8 +44,10 @@ int main()
 
 #else
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
 
 #endif
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/end.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/end.pass.cpp
index 8d287f6f799..86b00a3706d 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/end.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/end.pass.cpp
@@ -33,7 +33,7 @@ test(S s)
     assert(static_cast<std::size_t>(ce - cs.begin()) == cs.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -47,4 +47,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/iterators.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/iterators.pass.cpp
index 3d907602317..08448b1fd89 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/iterators.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/iterators.pass.cpp
@@ -20,7 +20,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     { // N3644 testing
         typedef std::string C;
@@ -83,4 +83,6 @@ int main()
         assert ( !(ii1 != ii2 ));
         assert ( !(ii1 != cii ));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/rbegin.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/rbegin.pass.cpp
index 8de45475f62..479584c3708 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/rbegin.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/rbegin.pass.cpp
@@ -30,7 +30,7 @@ test(S s)
     assert(b == cb);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -44,4 +44,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.iterators/rend.pass.cpp b/libcxx/test/std/strings/basic.string/string.iterators/rend.pass.cpp
index 1edcb27af07..9b54058a60d 100644
--- a/libcxx/test/std/strings/basic.string/string.iterators/rend.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.iterators/rend.pass.cpp
@@ -33,7 +33,7 @@ test(S s)
     assert(static_cast<std::size_t>(ce - cs.rbegin()) == cs.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -47,4 +47,6 @@ int main()
     test(S("123"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/nothing_to_do.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/T_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/T_size_size.pass.cpp
index f2848295baf..43752406362 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/T_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/T_size_size.pass.cpp
@@ -71,7 +71,7 @@ test_npos(S s, SV sv, typename S::size_type pos, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -196,4 +196,6 @@ int main()
     s.append(sv, 0, std::string::npos);
     assert(s == "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/initializer_list.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/initializer_list.pass.cpp
index 04483865d56..da74fb4e09c 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/initializer_list.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("123");
@@ -31,4 +31,6 @@ int main()
         s.append({'a', 'b', 'c'});
         assert(s == "123abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/iterator.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/iterator.pass.cpp
index 08f554b34d4..8f280e828d9 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/iterator.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/iterator.pass.cpp
@@ -42,7 +42,7 @@ test_exceptions(S s, It first, It last)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -219,4 +219,6 @@ int main()
     s.append(MoveIt(It(std::begin(p))), MoveIt(It(std::end(p) - 1)));
     assert(s == "ABCD");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer.pass.cpp
index dec79a67cd1..eba693d0e3d 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer.pass.cpp
@@ -26,7 +26,7 @@ test(S s, const typename S::value_type* str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -76,4 +76,6 @@ int main()
     s_long.append(s_long.c_str());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer_size.pass.cpp
index 2fb973ae983..c214ab7c2ac 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/pointer_size.pass.cpp
@@ -27,7 +27,7 @@ test(S s, const typename S::value_type* str, typename S::size_type n, S expected
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -85,4 +85,6 @@ int main()
     s_long.append(s_long.data(), s_long.size());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/push_back.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/push_back.pass.cpp
index a2b9ad1e470..f1b34ad6cff 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/push_back.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/push_back.pass.cpp
@@ -31,7 +31,7 @@ test(S s, typename S::value_type c, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -56,4 +56,6 @@ int main()
     s.push_back(vl);
     s.push_back(vl);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/size_char.pass.cpp
index 59d0199a2bf..c4062489291 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/size_char.pass.cpp
@@ -26,7 +26,7 @@ test(S s, typename S::size_type n, typename S::value_type c, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -60,4 +60,6 @@ int main()
     test(S("12345678901234567890"), 10, 'a', S("12345678901234567890aaaaaaaaaa"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string.pass.cpp
index c0c625f2e22..5e551d7a2b1 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string.pass.cpp
@@ -26,7 +26,7 @@ test(S s, S str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -85,4 +85,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_size_size.pass.cpp
index 21ddd9bb225..37985d00115 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_size_size.pass.cpp
@@ -71,7 +71,7 @@ test_npos(S s, S str, typename S::size_type pos, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -133,4 +133,6 @@ int main()
     test_npos(S(), S("12345"), 5, S(""));
     test_npos(S(), S("12345"), 6, S("not happening"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp
index 301fc77b704..d0fb1cc3315 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp
@@ -27,7 +27,7 @@ test(S s, SV sv, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -79,4 +79,6 @@ int main()
          S("1234567890123456789012345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/T_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/T_size_size.pass.cpp
index b0541712257..044b3724041 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/T_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/T_size_size.pass.cpp
@@ -70,7 +70,7 @@ test_npos(S s, SV sv, typename S::size_type pos, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -191,4 +191,6 @@ int main()
     s.assign(sv, 0, std::string::npos);
     assert(s == "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/initializer_list.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/initializer_list.pass.cpp
index 72097dae630..692b84b557d 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/initializer_list.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("123");
@@ -31,4 +31,6 @@ int main()
         s.assign({'a', 'b', 'c'});
         assert(s == "abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/iterator.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/iterator.pass.cpp
index 4bf805c99d6..c03b5efdfd5 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/iterator.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/iterator.pass.cpp
@@ -43,7 +43,7 @@ test_exceptions(S s, It first, It last)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -204,4 +204,6 @@ int main()
     s.assign(p, p + 4);
     assert(s == "ABCD");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer.pass.cpp
index 62a173a186d..325c354c56a 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer.pass.cpp
@@ -26,7 +26,7 @@ test(S s, const typename S::value_type* str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -74,4 +74,6 @@ int main()
     s_long.assign(s_long.c_str() + 30);
     assert(s_long == "nsectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer_size.pass.cpp
index 442d8c00024..5d3fe262184 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/pointer_size.pass.cpp
@@ -27,7 +27,7 @@ test(S s, const typename S::value_type* str, typename S::size_type n, S expected
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -85,4 +85,6 @@ int main()
     s_long.assign(s_long.data() + 2, 8 );
     assert(s_long == "rem ipsu");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/rv_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/rv_string.pass.cpp
index 3d401c8a917..ac26f369ddb 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/rv_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/rv_string.pass.cpp
@@ -27,7 +27,7 @@ test(S s, S str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -77,4 +77,6 @@ int main()
          S("12345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/size_char.pass.cpp
index 8c69b138f9f..4e5ecad2e9d 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/size_char.pass.cpp
@@ -26,7 +26,7 @@ test(S s, typename S::size_type n, typename S::value_type c, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -60,4 +60,6 @@ int main()
     test(S("12345678901234567890"), 10, 'a', S(10, 'a'));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp
index 274703a565d..fae45c80de0 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp
@@ -37,7 +37,7 @@ testAlloc(S s, S str, const typename S::allocator_type& a)
     assert(s.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -113,4 +113,6 @@ int main()
     static_assert(noexcept(S().assign(S())), "");  // LWG#2063
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_size_size.pass.cpp
index 76dd273455b..8e11b150e91 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_size_size.pass.cpp
@@ -71,7 +71,7 @@ test_npos(S s, S str, typename S::size_type pos, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -133,4 +133,6 @@ int main()
     test_npos(S(), S("12345"), 5, S(""));
     test_npos(S(), S("12345"), 6, S("not happening"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_view.pass.cpp
index d445ad9b793..2d1158e41de 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string_view.pass.cpp
@@ -38,7 +38,7 @@ testAlloc(S s, SV sv, const typename S::allocator_type& a)
     assert(s.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -101,4 +101,6 @@ int main()
     testAlloc(S(), SV("12345678901234567890"), min_allocator<char>());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp
index 81dc3329c43..778fb70c069 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp
@@ -49,7 +49,7 @@ test(S str, typename S::value_type* s, typename S::size_type n,
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -177,4 +177,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), s, 21, 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter.pass.cpp
index 1923c62b4d2..12b13d738cc 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter.pass.cpp
@@ -28,7 +28,7 @@ test(S s, typename S::difference_type pos, S expected)
     assert(i - s.begin() == pos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -62,4 +62,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), 19, S("abcdefghijklmnopqrs"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter_iter.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter_iter.pass.cpp
index 0eba9361d8a..a5e6d1251d1 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter_iter.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/iter_iter.pass.cpp
@@ -29,7 +29,7 @@ test(S s, typename S::difference_type pos, typename S::difference_type n, S expe
     assert(i - s.begin() == pos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -147,4 +147,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), 20, 0, S("abcdefghijklmnopqrst"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/pop_back.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/pop_back.pass.cpp
index e6f2a4e6035..e6490abcd2e 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/pop_back.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/pop_back.pass.cpp
@@ -26,7 +26,7 @@ test(S s, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -42,4 +42,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrs"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/size_size.pass.cpp
index a8e31c9c694..88dace52f8a 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_erase/size_size.pass.cpp
@@ -88,7 +88,7 @@ test(S s, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -298,4 +298,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S(""));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_char.pass.cpp
index d570428c054..ef6144dadb5 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_char.pass.cpp
@@ -32,7 +32,7 @@ test(S& s, typename S::const_iterator p, typename S::value_type c, S expected)
         assert(i == p);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -72,4 +72,6 @@ int main()
     test(s, s.begin()+6, 'C', S("a567ABC1432dcb"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_initializer_list.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_initializer_list.pass.cpp
index 0acc50b4549..6dd043c6db9 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_initializer_list.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_initializer_list.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("123456");
@@ -33,4 +33,6 @@ int main()
         assert(i - s.begin() == 3);
         assert(s == "123abc456");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_iter_iter.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_iter_iter.pass.cpp
index c1b16872928..6d4f1a6686e 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_iter_iter.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_iter_iter.pass.cpp
@@ -49,7 +49,7 @@ test_exceptions(S s, typename S::difference_type pos, It first, It last)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -218,4 +218,6 @@ int main()
     s.insert(s.begin(), MoveIt(It(std::begin(p))), MoveIt(It(std::end(p) - 1)));
     assert(s == "ABCD");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_size_char.pass.cpp
index ac29e3b3325..699b67924b1 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/iter_size_char.pass.cpp
@@ -28,7 +28,7 @@ test(S s, typename S::difference_type pos, typename S::size_type n,
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -166,4 +166,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), 20, 20, '1', S("abcdefghijklmnopqrst11111111111111111111"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_T_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_T_size_size.pass.cpp
index fb8c7e63a5c..2b54b67202b 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_T_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_T_size_size.pass.cpp
@@ -1729,7 +1729,7 @@ void test30()
     test_npos(S("abcdefghijklmnopqrst"), 10, SV("12345"), 6, S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -1838,4 +1838,6 @@ int main()
     assert(s == "");
     s.clear();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer.pass.cpp
index ee7ef204a33..24859fa8be2 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer.pass.cpp
@@ -47,7 +47,7 @@ test(S s, typename S::size_type pos, const typename S::value_type* str, S expect
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -233,4 +233,6 @@ int main()
     s_long.insert(0, s_long.c_str());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer_size.pass.cpp
index 67a03400528..3dbd93f1df5 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_pointer_size.pass.cpp
@@ -48,7 +48,7 @@ test(S s, typename S::size_type pos, const typename S::value_type* str,
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -714,4 +714,6 @@ int main()
     s_long.insert(0, s_long.data(), s_long.size());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_size_char.pass.cpp
index e64e9c997e3..dce8b7d7edb 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_size_char.pass.cpp
@@ -48,7 +48,7 @@ test(S s, typename S::size_type pos, typename S::size_type n,
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -218,4 +218,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), 21, 20, '1', S("can't happen"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string.pass.cpp
index 2f74fec3f79..93bc3f6d961 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string.pass.cpp
@@ -47,7 +47,7 @@ test(S s, typename S::size_type pos, S str, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -226,4 +226,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string_size_size.pass.cpp
index 23b8852b4c3..18a688a5d1f 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/size_string_size_size.pass.cpp
@@ -1727,7 +1727,7 @@ void test30()
     test_npos(S("abcdefghijklmnopqrst"), 10, S("12345"), 6, S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -1799,4 +1799,6 @@ int main()
     test30<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/string_view.pass.cpp
index 0596ce9849e..129389a9a7b 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_insert/string_view.pass.cpp
@@ -47,7 +47,7 @@ test(S s, typename S::size_type pos, SV sv, S expected)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -235,4 +235,6 @@ int main()
     s_long.insert(0, s_long.c_str());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/char.pass.cpp
index 3c15f6f919e..2cc4496eb67 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/char.pass.cpp
@@ -25,7 +25,7 @@ test(S s, typename S::value_type str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -43,4 +43,6 @@ int main()
     test(S("12345678901234567890"), 'a', S("12345678901234567890a"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/initializer_list.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/initializer_list.pass.cpp
index 7f27559f0e6..689389eb7a6 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/initializer_list.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("123");
@@ -30,4 +30,6 @@ int main()
         s += {'a', 'b', 'c'};
         assert(s == "123abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/pointer.pass.cpp
index 3a769693518..a9edf17be5b 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/pointer.pass.cpp
@@ -25,7 +25,7 @@ test(S s, const typename S::value_type* str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -75,4 +75,6 @@ int main()
          S("1234567890123456789012345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/string.pass.cpp
index 53e1cacf4a1..f81d4bec0d2 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_op_plus_equal/string.pass.cpp
@@ -26,7 +26,7 @@ test(S s, S str, S expected)
     assert(s == expected);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -85,4 +85,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_initializer_list.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_initializer_list.pass.cpp
index 8e8a1f8ef9e..3df49f32535 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_initializer_list.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_initializer_list.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("123def456");
@@ -30,4 +30,6 @@ int main()
         s.replace(s.cbegin() + 3, s.cbegin() + 6, {'a', 'b', 'c'});
         assert(s == "123abc456");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_iter_iter.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_iter_iter.pass.cpp
index fc6f33beafe..47a1193be73 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_iter_iter.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_iter_iter.pass.cpp
@@ -963,7 +963,7 @@ void test8()
     test(S("abcdefghijklmnopqrst"), 20, 0, str, str+20, S("abcdefghijklmnopqrst12345678901234567890"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -1036,4 +1036,6 @@ int main()
     s.replace(s.begin(), s.end(), p, p + 4);
     assert(s == "EFGH");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer.pass.cpp
index ccbd0ff66fb..8ed1dc3df30 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer.pass.cpp
@@ -265,7 +265,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 20, 0, "12345678901234567890", S("abcdefghijklmnopqrst12345678901234567890"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -297,4 +297,6 @@ int main()
     s_long.replace(s_long.begin(), s_long.begin(), s_long.c_str());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer_size.pass.cpp
index 79ae58fce2e..39b518c9146 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_pointer_size.pass.cpp
@@ -943,7 +943,7 @@ void test8()
     test(S("abcdefghijklmnopqrst"), 20, 0, "12345678901234567890", 20, S("abcdefghijklmnopqrst12345678901234567890"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -987,4 +987,6 @@ int main()
     s_long.replace(s_long.begin(), s_long.begin(), s_long.data(), s_long.size());
     assert(s_long == "Lorem ipsum dolor sit amet, consectetur/Lorem ipsum dolor sit amet, consectetur/");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_size_char.pass.cpp
index 8a79b733fe2..e60c69f7a27 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_size_char.pass.cpp
@@ -265,7 +265,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 20, 0, 20, '3', S("abcdefghijklmnopqrst33333333333333333333"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -281,4 +281,6 @@ int main()
     test2<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string.pass.cpp
index b47d2931b9b..7008736610f 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string.pass.cpp
@@ -264,7 +264,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 20, 0, S("12345678901234567890"), S("abcdefghijklmnopqrst12345678901234567890"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -289,4 +289,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string_view.pass.cpp
index 81ecca69fb3..0acf8286853 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string_view.pass.cpp
@@ -264,7 +264,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 20, 0, SV("12345678901234567890"), S("abcdefghijklmnopqrst12345678901234567890"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -282,4 +282,6 @@ int main()
     test2<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_T_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_T_size_size.pass.cpp
index b320eff372c..2348747def0 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_T_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_T_size_size.pass.cpp
@@ -5869,7 +5869,7 @@ void test55()
     test_npos(S("abcdefghij"), 9, 2, SV("12345"), 6, S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -6025,4 +6025,6 @@ int main()
     s.replace(0, 4, arr, 0, std::string::npos);    // calls replace(pos1, n1, string("IJKL"), pos, npos)
     assert(s == "IJKL");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer.pass.cpp
index 6718242e0e8..a6a6c7d9dcf 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer.pass.cpp
@@ -363,7 +363,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, "12345678901234567890", S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -379,4 +379,6 @@ int main()
     test2<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer_size.pass.cpp
index 53465bf680e..e3056670704 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_pointer_size.pass.cpp
@@ -1297,7 +1297,7 @@ void test11()
     test(S("abcdefghijklmnopqrst"), 21, 0, "12345678901234567890", 20, S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -1331,4 +1331,6 @@ int main()
     test11<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_size_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_size_char.pass.cpp
index 2e8c4527cc7..7d37e107561 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_size_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_size_char.pass.cpp
@@ -364,7 +364,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, 20, '2', S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -380,4 +380,6 @@ int main()
     test2<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string.pass.cpp
index 85306d59595..c0fad33a398 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string.pass.cpp
@@ -362,7 +362,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, S("12345678901234567890"), S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -387,4 +387,6 @@ int main()
     assert(s == "a");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_size_size.pass.cpp
index 7a75f03e59b..3fa32699fda 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_size_size.pass.cpp
@@ -5859,7 +5859,7 @@ void test55()
     test_npos(S("abcdefghij"), 9, 2, S("12345"), 6, S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -5981,4 +5981,6 @@ int main()
     test55<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_view.pass.cpp
index 9b35da025f9..542220aea70 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string_view.pass.cpp
@@ -362,7 +362,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, SV("12345678901234567890"), S("can't happen"));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -380,4 +380,6 @@ int main()
     test2<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_swap/swap.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_swap/swap.pass.cpp
index 79adee48764..8fdf3fea9b4 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_swap/swap.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_swap/swap.pass.cpp
@@ -31,7 +31,7 @@ test(S s1, S s2)
     assert(s2 == s1_);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -73,4 +73,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("12345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/nothing_to_do.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line.pass.cpp
index 9937863b28a..8e663cb4f60 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream in(" abc\n  def\n   ghij");
@@ -77,4 +77,6 @@ int main()
         assert(s == L"   ghij");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim.pass.cpp
index 965137c1d30..b081b55c920 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream in(" abc*  def**   ghij");
@@ -89,4 +89,6 @@ int main()
         assert(s == L"   ghij");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim_rv.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim_rv.pass.cpp
index b2255d068b2..b1511f21192 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim_rv.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_delim_rv.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("initial text");
@@ -45,4 +45,6 @@ int main()
         getline(std::wistringstream(L" abc*  def*   ghij"), s, L'*');
         assert(s == L" abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_rv.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_rv.pass.cpp
index a87529a0eab..cf4772c43d3 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_rv.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/get_line_rv.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::string s("initial text");
@@ -45,4 +45,6 @@ int main()
         getline(std::wistringstream(L" abc\n  def\n   ghij"), s);
         assert(s == L" abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_extract.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_extract.pass.cpp
index 85f399dcd0d..389701d1d51 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_extract.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_extract.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream in("a bc defghij");
@@ -113,4 +113,6 @@ int main()
         assert(in.fail());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_insert.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_insert.pass.cpp
index eb272c29bc6..b30fd5afaf5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_insert.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.io/stream_insert.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream out;
@@ -87,4 +87,6 @@ int main()
         assert(L"   " + s == out.str());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp
index 944bd455391..f644f287075 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp
@@ -33,7 +33,7 @@ test(S s1, S s2)
     assert(s2 == s1_);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -75,4 +75,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("12345678901234567890"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp
index a00eb17be59..3f6ce447cf7 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp
@@ -53,7 +53,7 @@ struct some_alloc2
     typedef std::true_type is_always_equal;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::string C;
@@ -81,4 +81,6 @@ int main()
         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp
index 527d59d6887..bf2cc8413ab 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp
@@ -23,7 +23,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x)
     assert((lhs != rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp
index b1e6fa73d4f..76e0abe2378 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp
@@ -23,7 +23,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x)
     assert((lhs != rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp
index 9825c1b3830..30aeb501a59 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp
@@ -24,7 +24,7 @@ test(const S& lhs, const S& rhs, bool x)
     assert((lhs != rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp
index 7108d819e0b..5b01455e7f8 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp
@@ -22,7 +22,7 @@ test(const S& lhs, SV rhs, bool x)
     assert((lhs != rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp
index 8f3906bf18b..2d6957e3494 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp
@@ -22,7 +22,7 @@ test(SV lhs, const S& rhs, bool x)
     assert((lhs != rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp
index c24d8076842..9ab3c061197 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp
@@ -35,7 +35,7 @@ void test1(typename S::value_type lhs, S&& rhs, const S& x) {
 }
 #endif
 
-int main() {
+int main(int, char**) {
   {
     typedef std::string S;
     test0('a', S(""), S("a"));
@@ -66,4 +66,6 @@ int main() {
     test1('a', S("12345678901234567890"), S("a12345678901234567890"));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp
index 654eca290f5..cf13fbb51d6 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp
@@ -35,7 +35,7 @@ void test1(const typename S::value_type* lhs, S&& rhs, const S& x) {
 }
 #endif
 
-int main() {
+int main(int, char**) {
   {
     typedef std::string S;
     test0("", S(""), S(""));
@@ -127,4 +127,6 @@ int main() {
           S("abcdefghijklmnopqrst12345678901234567890"));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp
index 5196aba1a69..32411144db2 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp
@@ -35,7 +35,7 @@ void test1(S&& lhs, typename S::value_type rhs, const S& x) {
 }
 #endif
 
-int main() {
+int main(int, char**) {
   {
     typedef std::string S;
     test0(S(""), '1', S("1"));
@@ -66,4 +66,6 @@ int main() {
     test1(S("abcdefghijklmnopqrst"), '1', S("abcdefghijklmnopqrst1"));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp
index ef8b8001009..4fec8482966 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp
@@ -35,7 +35,7 @@ void test1(S&& lhs, const typename S::value_type* rhs, const S& x) {
 }
 #endif
 
-int main() {
+int main(int, char**) {
   {
     typedef std::string S;
     test0(S(""), "", S(""));
@@ -126,4 +126,6 @@ int main() {
           S("abcdefghijklmnopqrst12345678901234567890"));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp
index 2bc38c71a00..00aaf5cc092 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp
@@ -58,7 +58,7 @@ void test3(S&& lhs, S&& rhs, const S& x) {
 
 #endif
 
-int main() {
+int main(int, char**) {
   {
     typedef std::string S;
     test0(S(""), S(""), S(""));
@@ -245,4 +245,6 @@ int main() {
           S("abcdefghijklmnopqrst12345678901234567890"));
   }
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp
index 11ad5f15194..5db04b3a8d6 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp
@@ -23,7 +23,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x)
     assert((lhs == rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp
index f020c2234f3..aa79e17d121 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp
@@ -23,7 +23,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x)
     assert((lhs == rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp
index 39ec5cc06e4..357a91fd9f5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp
@@ -24,7 +24,7 @@ test(const S& lhs, const S& rhs, bool x)
     assert((lhs == rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp
index f4791e3b54c..06c16d07079 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp
@@ -22,7 +22,7 @@ test(const S& lhs, SV rhs, bool x)
     assert((lhs == rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp
index fdf89a2c9c4..7ebdc093493 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp
@@ -22,7 +22,7 @@ test(SV lhs, const S& rhs, bool x)
     assert((lhs == rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp
index dd27087b66c..db28cd4d1b4 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp
@@ -23,7 +23,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x)
     assert((lhs > rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp
index 4109eab3336..56521e91662 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp
@@ -23,7 +23,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x)
     assert((lhs > rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp
index 3514ffc11bc..0cfafb80911 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp
@@ -24,7 +24,7 @@ test(const S& lhs, const S& rhs, bool x)
     assert((lhs > rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp
index 8ad82bf01f2..692fbd4fe81 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp
@@ -22,7 +22,7 @@ test(const S& lhs, SV rhs, bool x)
     assert((lhs > rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp
index af98fa15363..f6a2fa55588 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp
@@ -22,7 +22,7 @@ test(SV lhs, const S& rhs, bool x)
     assert((lhs > rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp
index 0d7e5acea1c..e868531a683 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp
@@ -23,7 +23,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x)
     assert((lhs >= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp
index 93b9d2a874d..8aad5078247 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp
@@ -23,7 +23,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x)
     assert((lhs >= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp
index 06f23205904..f0ab16cbb62 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp
@@ -24,7 +24,7 @@ test(const S& lhs, const S& rhs, bool x)
     assert((lhs >= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp
index 27c2b35d355..c7eb3e3e45e 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp
@@ -22,7 +22,7 @@ test(const S& lhs, SV rhs, bool x)
     assert((lhs >= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp
index ff4a35b39bf..b49c1348a99 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp
@@ -22,7 +22,7 @@ test(SV lhs, const S& rhs, bool x)
     assert((lhs >= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp
index 0c3943d7db2..1609c4d87d9 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp
@@ -23,7 +23,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x)
     assert((lhs < rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp
index d91c3b1aeef..079344bb829 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp
@@ -23,7 +23,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x)
     assert((lhs < rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp
index 0b05b6c3592..586faa40f07 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp
@@ -24,7 +24,7 @@ test(const S& lhs, const S& rhs, bool x)
     assert((lhs < rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp
index eec351c24ec..79393def5dd 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp
@@ -22,7 +22,7 @@ test(const S& lhs, SV rhs, bool x)
     assert((lhs < rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp
index 9b2b7ddd9a3..7e8b139c332 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp
@@ -22,7 +22,7 @@ test(SV lhs, const S& rhs, bool x)
     assert((lhs < rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp
index 5354e6b75c4..cae9233dfb2 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp
@@ -23,7 +23,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x)
     assert((lhs <= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp
index 5fe8948dd61..07f9b355185 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp
@@ -23,7 +23,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x)
     assert((lhs <= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -65,4 +65,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp
index 1261f518541..8d40f2f0a5b 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp
@@ -24,7 +24,7 @@ test(const S& lhs, const S& rhs, bool x)
     assert((lhs <= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp
index bdaa49a63a1..3df9e39cc0d 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp
@@ -22,7 +22,7 @@ test(const S& lhs, SV rhs, bool x)
     assert((lhs <= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp
index 64d286cd890..cb7b1a4c451 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp
@@ -22,7 +22,7 @@ test(SV lhs, const S& rhs, bool x)
     assert((lhs <= rhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -66,4 +66,6 @@ int main()
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/nothing_to_do.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string.accessors/c_str.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string.accessors/c_str.pass.cpp
index 7c713e4b0b3..2677230c2d5 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string.accessors/c_str.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string.accessors/c_str.pass.cpp
@@ -30,7 +30,7 @@ test(const S& s)
         assert(T::eq(str[0], typename S::value_type()));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -48,4 +48,6 @@ int main()
     test(S("abcdefghijklmnopqrst"));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string.accessors/data.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string.accessors/data.pass.cpp
index 9c643a17236..6aa07302a95 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string.accessors/data.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string.accessors/data.pass.cpp
@@ -47,7 +47,7 @@ test_nonconst(S& s)
         assert(T::eq(str[0], typename S::value_type()));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -74,4 +74,6 @@ int main()
     S s4("abcdefghijklmnopqrst"); test_nonconst(s4);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string.accessors/get_allocator.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string.accessors/get_allocator.pass.cpp
index 6261ad55f1a..7edf5a88d9d 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string.accessors/get_allocator.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string.accessors/get_allocator.pass.cpp
@@ -23,7 +23,7 @@ test(const S& s, const typename S::allocator_type& a)
     assert(s.get_allocator() == a);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef test_allocator<char> A;
@@ -43,4 +43,6 @@ int main()
     test(S("abcdefghijklmnopqrst", A()), A());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/pointer.pass.cpp
index 6219d6babfc..0af8ce02f95 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/pointer.pass.cpp
@@ -31,7 +31,7 @@ test(const S& s, const typename S::value_type* str, int x)
     assert(sign(s.compare(str)) == sign(x));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -73,4 +73,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_T_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_T_size_size.pass.cpp
index ad781f23c26..abab9879a14 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_T_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_T_size_size.pass.cpp
@@ -5840,7 +5840,7 @@ void test55()
     test_npos(S("abcde"), 0, 0, SV("abcdefghij"), 5, -5);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -5989,4 +5989,6 @@ int main()
 //  calls compare(size, size, string(arr), 0, npos)
     assert(s.compare(0, 4, arr, 0, std::string::npos) == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer.pass.cpp
index aa44e16a9c3..4e77fc09c8e 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer.pass.cpp
@@ -361,7 +361,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, "abcdefghijklmnopqrst", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -377,4 +377,6 @@ int main()
     test2<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer_size.pass.cpp
index f9c0244ec3f..75efbadcc81 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_pointer_size.pass.cpp
@@ -1294,7 +1294,7 @@ void test11()
     test(S("abcdefghijklmnopqrst"), 21, 0, "abcdefghijklmnopqrst", 20, 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -1328,4 +1328,6 @@ int main()
     test11<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string.pass.cpp
index 06b5e531018..55fd823718e 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string.pass.cpp
@@ -360,7 +360,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, S("abcdefghijklmnopqrst"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     assert(s.compare(0, 1, {"abc", 1}) < 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_size_size.pass.cpp
index 6a231a867c3..05ba6ac82c5 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_size_size.pass.cpp
@@ -5836,7 +5836,7 @@ void test55()
     test_npos(S("abcde"), 0, 0, S("abcdefghij"), 5, -5);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -5958,4 +5958,6 @@ int main()
     test55<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_view.pass.cpp
index 00245e834d7..94c73ab31a6 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/size_size_string_view.pass.cpp
@@ -361,7 +361,7 @@ void test2()
     test(S("abcdefghijklmnopqrst"), 21, 0, SV("abcdefghijklmnopqrst"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -379,4 +379,6 @@ int main()
     test2<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/string.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/string.pass.cpp
index 7c3bdb1595e..279ae307584 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/string.pass.cpp
@@ -32,7 +32,7 @@ test(const S& s, const S& str, int x)
     assert(sign(s.compare(str)) == sign(x));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -81,4 +81,6 @@ int main()
     assert(s.compare({"abc", 1}) < 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_compare/string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_compare/string_view.pass.cpp
index 3e123ad7ace..2abc7fc1ac1 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_compare/string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_compare/string_view.pass.cpp
@@ -31,7 +31,7 @@ test(const S& s, SV sv, int x)
     assert(sign(s.compare(sv)) == sign(x));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -75,4 +75,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/char_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/char_size.pass.cpp
index 2c4994670c8..7bada8446ff 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/char_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -98,4 +98,6 @@ int main()
     test(S("laenfsbridchgotmkqpj"), 'q', 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size.pass.cpp
index cb6fc1e9728..bd20ea1bb4a 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -154,4 +154,6 @@ int main()
     test1<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size_size.pass.cpp
index 708a04352f9..46c5511d9ae 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     test3<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_size.pass.cpp
index 1ea41354f28..7f12ab1ba27 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     assert(s.find_first_not_of({"abc", 1}) == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_view_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_view_size.pass.cpp
index 3cb3e74204d..54ce737ecc6 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.not.of/string_view_size.pass.cpp
@@ -139,7 +139,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), SV("htaobedqikfplcgjsmrn"), S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -155,4 +155,6 @@ int main()
     test1<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/char_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/char_size.pass.cpp
index cf8548744f8..da630f07e76 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/char_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -94,4 +94,6 @@ int main()
     test(S("laenfsbridchgotmkqpj"), 'e', 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size.pass.cpp
index 4c435537c46..2162ea14cf1 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -154,4 +154,6 @@ int main()
     test1<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size_size.pass.cpp
index c8b62b1f454..e0bb0f2fb77 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     test3<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_size.pass.cpp
index fc79c89d151..1ae2123c3eb 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     assert(s.find_first_of({"abc", 1}) == std::string::npos);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_view_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_view_size.pass.cpp
index ae29e47481b..8cd272408a0 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.first.of/string_view_size.pass.cpp
@@ -139,7 +139,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), SV("htaobedqikfplcgjsmrn"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -155,4 +155,6 @@ int main()
     test1<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/char_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/char_size.pass.cpp
index 6276c491075..fd77eb89d86 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/char_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -94,4 +94,6 @@ int main()
     test(S("laenfsbridchgotmkqpj"), 'i', 19);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size.pass.cpp
index 5cc9c0bf40a..1234ccb4de2 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -154,4 +154,6 @@ int main()
     test1<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size_size.pass.cpp
index 76834c2e81d..4c07f4d6129 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     test3<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_size.pass.cpp
index 254e639dcfb..8232612c1e7 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     assert(s.find_last_not_of({"abc", 1}) == s.size() - 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_view_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_view_size.pass.cpp
index 421ec966db2..da5054b7df6 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.not.of/string_view_size.pass.cpp
@@ -139,7 +139,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), SV("htaobedqikfplcgjsmrn"), S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -155,4 +155,6 @@ int main()
 //     test1<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/char_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/char_size.pass.cpp
index 2c5359e5edf..4292b1eb8bf 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/char_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -94,4 +94,6 @@ int main()
     test(S("laenfsbridchgotmkqpj"), 'm', 15);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size.pass.cpp
index 6a320788d4b..0b86a10c512 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -154,4 +154,6 @@ int main()
     test1<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size_size.pass.cpp
index 46d61a44aec..9c5f670a9c7 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     test3<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_size.pass.cpp
index c5f1a3a7d96..f3ddb468d49 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     assert(s.find_last_of({"abc", 1}) == std::string::npos);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_view_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_view_size.pass.cpp
index f98d66eec45..ccf181faa55 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find.last.of/string_view_size.pass.cpp
@@ -139,7 +139,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), SV("htaobedqikfplcgjsmrn"), 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -155,4 +155,6 @@ int main()
     test1<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find/char_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find/char_size.pass.cpp
index c346a0196f3..5700d09575f 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find/char_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find/char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(0 <= x && x + 1 <= s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -94,4 +94,6 @@ int main()
     test(S("abcdeabcdeabcdeabcde"), 'c', 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size.pass.cpp
index a6136d3f844..6e7ae3d41f4 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size.pass.cpp
@@ -146,7 +146,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -160,4 +160,6 @@ int main()
     test1<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size_size.pass.cpp
index 176ffbb563a..fad7507173d 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find/pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     test3<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find/string_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find/string_size.pass.cpp
index 482648ab3b0..e8a91dd1f67 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find/string_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find/string_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), S("abcdeabcdeabcdeabcde"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     assert(s.find({"abc", 1}) == std::string::npos);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_find/string_view_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_find/string_view_size.pass.cpp
index d84a41e4ca8..c1e78af1025 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_find/string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_find/string_view_size.pass.cpp
@@ -139,7 +139,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), SV("abcdeabcdeabcdeabcde"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -155,4 +155,6 @@ int main()
     test1<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/char_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/char_size.pass.cpp
index 9a30a63d172..46ced312391 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/char_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x + 1 <= s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -94,4 +94,6 @@ int main()
     test(S("abcdeabcdeabcdeabcde"), 'b', 16);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size.pass.cpp
index 57a4d06bd13..715b5e57855 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size.pass.cpp
@@ -147,7 +147,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     test1<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size_size.pass.cpp
index 786affd27bc..e9670095227 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 20, 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -383,4 +383,6 @@ int main()
     test3<S>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_size.pass.cpp
index c83acbf4d5d..74cfb02ee28 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), S("abcdeabcdeabcdeabcde"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -161,4 +161,6 @@ int main()
     assert(s.rfind({"abc", 1}) == std::string::npos);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_view_size.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_view_size.pass.cpp
index 3657e028c2e..ea4f9c20597 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_rfind/string_view_size.pass.cpp
@@ -139,7 +139,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), SV("abcdeabcdeabcdeabcde"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -155,4 +155,6 @@ int main()
     test1<S, SV>();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp
index 767dc506339..27af66e0670 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp
@@ -47,7 +47,7 @@ test(const S& s, typename S::size_type pos, typename S::size_type n)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -173,4 +173,6 @@ int main()
     test(S("dplqartnfgejichmoskb"), 21, 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.require/contiguous.pass.cpp b/libcxx/test/std/strings/basic.string/string.require/contiguous.pass.cpp
index fb2e3e6ce6b..be090c90e17 100644
--- a/libcxx/test/std/strings/basic.string/string.require/contiguous.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.require/contiguous.pass.cpp
@@ -24,7 +24,7 @@ void test_contiguous ( const C &c )
         assert ( *(c.begin() + static_cast<typename C::difference_type>(i)) == *(std::addressof(*c.begin()) + i));
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -49,4 +49,6 @@ int main()
     test_contiguous(S("1234567890123456789012345678901234567890123456789012345678901234567890", A()));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.char.pass.cpp b/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.char.pass.cpp
index bc9fb26a5d2..8eae5f7c86c 100644
--- a/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.char.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -30,4 +30,6 @@ int main()
     assert ( s2.starts_with('a'));
     assert (!s2.starts_with('x'));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.ptr.pass.cpp b/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.ptr.pass.cpp
index ff46fc33d91..412ed574c78 100644
--- a/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.ptr.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.ptr.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -58,4 +58,6 @@ int main()
     assert (!sNot.starts_with("abcde"));
     assert ( sNot.starts_with("def"));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.string_view.pass.cpp
index acb90a0c8b1..c951b4c7374 100644
--- a/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.starts_with/starts_with.string_view.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string S;
@@ -68,4 +68,6 @@ int main()
     assert (!sNot.starts_with(sv5));
     assert ( sNot.starts_with(svNot));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/traits_mismatch.fail.cpp b/libcxx/test/std/strings/basic.string/traits_mismatch.fail.cpp
index 7e57ae1a7b1..47524d2c34d 100644
--- a/libcxx/test/std/strings/basic.string/traits_mismatch.fail.cpp
+++ b/libcxx/test/std/strings/basic.string/traits_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <string>
 
-int main()
+int main(int, char**)
 {
     std::basic_string<char, std::char_traits<wchar_t>> s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/types.pass.cpp b/libcxx/test/std/strings/basic.string/types.pass.cpp
index 0d074fe05fb..5aa2c7cf8be 100644
--- a/libcxx/test/std/strings/basic.string/types.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/types.pass.cpp
@@ -70,7 +70,7 @@ test()
     static_assert(S::npos == -1, "");
 }
 
-int main()
+int main(int, char**)
 {
     test<test_traits<char>, test_allocator<char> >();
     test<std::char_traits<wchar_t>, std::allocator<wchar_t> >();
@@ -81,4 +81,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<std::char_traits<char>, min_allocator<char> >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/c.strings/cctype.pass.cpp b/libcxx/test/std/strings/c.strings/cctype.pass.cpp
index feb5c29d22f..c26c1e6a20f 100644
--- a/libcxx/test/std/strings/c.strings/cctype.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cctype.pass.cpp
@@ -70,7 +70,7 @@
 #error toupper defined
 #endif
 
-int main()
+int main(int, char**)
 {
 
     ASSERT_SAME_TYPE(int, decltype(std::isalnum(0)));
@@ -102,4 +102,6 @@ int main()
     assert( std::isxdigit('a'));
     assert( std::tolower('A') == 'a');
     assert( std::toupper('a') == 'A');
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/c.strings/cstring.pass.cpp b/libcxx/test/std/strings/c.strings/cstring.pass.cpp
index c61f5c4ff8a..c8ee2789df4 100644
--- a/libcxx/test/std/strings/c.strings/cstring.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cstring.pass.cpp
@@ -17,7 +17,7 @@
 #error NULL not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::size_t s = 0;
     void* vp = 0;
@@ -60,4 +60,6 @@ int main()
     ASSERT_SAME_TYPE(const char*, decltype(std::strrchr(cpc, 0)));
     ASSERT_SAME_TYPE(const char*, decltype(std::strstr(cpc, cpc)));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/c.strings/cuchar.pass.cpp b/libcxx/test/std/strings/c.strings/cuchar.pass.cpp
index 989ca6b0427..4271503d4e2 100644
--- a/libcxx/test/std/strings/c.strings/cuchar.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cuchar.pass.cpp
@@ -14,6 +14,8 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/c.strings/cwchar.pass.cpp b/libcxx/test/std/strings/c.strings/cwchar.pass.cpp
index c7558859e1b..667910bc1a1 100644
--- a/libcxx/test/std/strings/c.strings/cwchar.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cwchar.pass.cpp
@@ -31,7 +31,7 @@
 #error WEOF not defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::mbstate_t mb = {};
     std::size_t s = 0;
@@ -128,4 +128,6 @@ int main()
     ASSERT_SAME_TYPE(int,                decltype(std::vwprintf(L"", va)));
     ASSERT_SAME_TYPE(int,                decltype(std::wprintf(L"")));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/c.strings/cwctype.pass.cpp b/libcxx/test/std/strings/c.strings/cwctype.pass.cpp
index a7d9560d71e..3bcda1a472c 100644
--- a/libcxx/test/std/strings/c.strings/cwctype.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cwctype.pass.cpp
@@ -90,7 +90,7 @@
 #error wctrans defined
 #endif
 
-int main()
+int main(int, char**)
 {
     std::wint_t w = 0;
     ASSERT_SAME_TYPE(int, decltype(std::iswalnum(w)));
@@ -113,4 +113,6 @@ int main()
     ASSERT_SAME_TYPE(std::wint_t,    decltype(std::towupper(w)));
     ASSERT_SAME_TYPE(std::wint_t,    decltype(std::towctrans(w, std::wctrans_t())));
     ASSERT_SAME_TYPE(std::wctrans_t, decltype(std::wctrans("")));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.require/nothing_to_do.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.require/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.require/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.require/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign2.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign2.pass.cpp
index 8f80a53ed70..c60e6db9fc4 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign2.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign2.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     char c = '\0';
     std::char_traits<char>::assign(c, 'a');
@@ -36,4 +36,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign3.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign3.pass.cpp
index 74e0f907672..e2cbe3d5dbe 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign3.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/assign3.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     char s2[3] = {0};
     assert(std::char_traits<char>::assign(s2, 3, char(5)) == s2);
@@ -23,4 +23,6 @@ int main()
     assert(s2[1] == char(5));
     assert(s2[2] == char(5));
     assert(std::char_traits<char>::assign(NULL, 0, char(5)) == NULL);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/compare.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/compare.pass.cpp
index 637095127bc..4926b6296e7 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/compare.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/compare.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::compare("", "", 0) == 0);
     assert(std::char_traits<char>::compare(NULL, NULL, 0) == 0);
@@ -53,4 +53,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/copy.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/copy.pass.cpp
index bd12bfd21e4..3a8e3bda6bc 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/copy.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/copy.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     char s1[] = {1, 2, 3};
     char s2[3] = {0};
@@ -25,4 +25,6 @@ int main()
     assert(s2[2] == char(3));
     assert(std::char_traits<char>::copy(NULL, s1, 0) == NULL);
     assert(std::char_traits<char>::copy(s1, NULL, 0) == s1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eof.pass.cpp
index ad99e30b24e..0ea0995da1f 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eof.pass.cpp
@@ -15,7 +15,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::eof() == EOF);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp
index 7895baf9975..f0cef792d14 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp
@@ -15,8 +15,10 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::eq('a', 'a'));
     assert(!std::char_traits<char>::eq('a', 'A'));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq_int_type.pass.cpp
index ca6808f865c..0fbb4389c60 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq_int_type.pass.cpp
@@ -15,11 +15,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert( std::char_traits<char>::eq_int_type('a', 'a'));
     assert(!std::char_traits<char>::eq_int_type('a', 'A'));
     assert(!std::char_traits<char>::eq_int_type(std::char_traits<char>::eof(), 'A'));
     assert( std::char_traits<char>::eq_int_type(std::char_traits<char>::eof(),
                                                 std::char_traits<char>::eof()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/find.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/find.pass.cpp
index 242d3a17392..97450084080 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/find.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/find.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     char s1[] = {1, 2, 3};
     assert(std::char_traits<char>::find(s1, 3, char(1)) == s1);
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/length.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/length.pass.cpp
index f556c952eac..8be4e0a7055 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/length.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/length.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 #endif
 
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::length("") == 0);
     assert(std::char_traits<char>::length("a") == 1);
@@ -38,4 +38,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/lt.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/lt.pass.cpp
index 497679636ec..e62090cf4c4 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/lt.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/lt.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert( std::char_traits<char>::lt('\0', 'A'));
     assert(!std::char_traits<char>::lt('A', '\0'));
@@ -29,4 +29,6 @@ int main()
 
     assert( std::char_traits<char>::lt(' ', 'A'));
     assert( std::char_traits<char>::lt('A', '~'));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/move.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/move.pass.cpp
index c1f885939ba..ecbb61901a9 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/move.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/move.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     char s1[] = {1, 2, 3};
     assert(std::char_traits<char>::move(s1, s1+1, 2) == s1);
@@ -29,4 +29,6 @@ int main()
     assert(s1[2] == char(3));
     assert(std::char_traits<char>::move(NULL, s1, 0) == NULL);
     assert(std::char_traits<char>::move(s1, NULL, 0) == s1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/not_eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/not_eof.pass.cpp
index 01568e5a428..1c37a7c2efb 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/not_eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/not_eof.pass.cpp
@@ -15,11 +15,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::not_eof('a') == 'a');
     assert(std::char_traits<char>::not_eof('A') == 'A');
     assert(std::char_traits<char>::not_eof(0) == 0);
     assert(std::char_traits<char>::not_eof(std::char_traits<char>::eof()) !=
            std::char_traits<char>::eof());
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_char_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_char_type.pass.cpp
index fbf8f2f584b..d8a957016f9 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_char_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_char_type.pass.cpp
@@ -15,9 +15,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::to_char_type('a') == 'a');
     assert(std::char_traits<char>::to_char_type('A') == 'A');
     assert(std::char_traits<char>::to_char_type(0) == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_int_type.pass.cpp
index eb8df3b6913..dd903f9e6c0 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/to_int_type.pass.cpp
@@ -15,9 +15,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char>::to_int_type('a') == 'a');
     assert(std::char_traits<char>::to_int_type('A') == 'A');
     assert(std::char_traits<char>::to_int_type(0) == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/types.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/types.pass.cpp
index 6439c1ea07e..30d31ebc920 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/types.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/types.pass.cpp
@@ -19,11 +19,13 @@
 #include <string>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::char_traits<char>::char_type, char>::value), "");
     static_assert((std::is_same<std::char_traits<char>::int_type, int>::value), "");
     static_assert((std::is_same<std::char_traits<char>::off_type, std::streamoff>::value), "");
     static_assert((std::is_same<std::char_traits<char>::pos_type, std::streampos>::value), "");
     static_assert((std::is_same<std::char_traits<char>::state_type, std::mbstate_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign2.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign2.pass.cpp
index 77b8687e8c6..017d0e7acce 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign2.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign2.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -40,4 +40,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign3.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign3.pass.cpp
index c623baa248c..8838b81e14b 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign3.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/assign3.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char16_t s2[3] = {0};
@@ -25,4 +25,6 @@ int main()
     assert(s2[2] == char16_t(5));
     assert(std::char_traits<char16_t>::assign(NULL, 0, char16_t(5)) == NULL);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/compare.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/compare.pass.cpp
index 2e3b18aca07..d0782c09338 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/compare.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/compare.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool test_constexpr()
 #endif
 
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -58,4 +58,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/copy.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/copy.pass.cpp
index 0bf5d47eeb5..102f15acdee 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/copy.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/copy.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char16_t s1[] = {1, 2, 3};
@@ -27,4 +27,6 @@ int main()
     assert(std::char_traits<char16_t>::copy(NULL, s1, 0) == NULL);
     assert(std::char_traits<char16_t>::copy(s1, NULL, 0) == s1);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp
index bb0a4506a9a..c80b0792a49 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp
@@ -15,10 +15,12 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     std::char_traits<char16_t>::int_type i = std::char_traits<char16_t>::eof();
     ((void)i); // Prevent unused warning
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp
index f4abe84dbd6..1c705109f28 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -25,4 +25,6 @@ int main()
     assert(!std::char_traits<char16_t>::eq(u'a', u'A'));
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq_int_type.pass.cpp
index 9a24cf13d0c..bef97d612eb 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq_int_type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -28,4 +28,6 @@ int main()
     assert( std::char_traits<char16_t>::eq_int_type(std::char_traits<char16_t>::eof(),
                                                     std::char_traits<char16_t>::eof()));
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/find.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/find.pass.cpp
index cd31e5925de..2ca7e534327 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/find.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/find.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char16_t s1[] = {1, 2, 3};
@@ -44,4 +44,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/length.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/length.pass.cpp
index 2a2a35702fc..f487c410b0b 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/length.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/length.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -41,4 +41,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp
index 4ade9b6f06d..a43a9e45cc2 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -25,4 +25,6 @@ int main()
     assert( std::char_traits<char16_t>::lt(u'A', u'a'));
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/move.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/move.pass.cpp
index ddf07a022c9..aa55e0d11ce 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/move.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/move.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char16_t s1[] = {1, 2, 3};
@@ -31,4 +31,6 @@ int main()
     assert(std::char_traits<char16_t>::move(NULL, s1, 0) == NULL);
     assert(std::char_traits<char16_t>::move(s1, NULL, 0) == s1);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/not_eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/not_eof.pass.cpp
index ea6f0ab17cd..bf26b4cf330 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/not_eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/not_eof.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -28,4 +28,6 @@ int main()
     assert(std::char_traits<char16_t>::not_eof(std::char_traits<char16_t>::eof()) !=
            std::char_traits<char16_t>::eof());
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_char_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_char_type.pass.cpp
index 9256a528172..738754bf983 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_char_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_char_type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -26,4 +26,6 @@ int main()
 #endif
     assert(std::char_traits<char16_t>::to_char_type(0) == 0);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_int_type.pass.cpp
index 411f5202b11..83fff60b886 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/to_int_type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -26,4 +26,6 @@ int main()
 #endif
     assert(std::char_traits<char16_t>::to_int_type(0) == 0);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/types.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/types.pass.cpp
index ae8792c4901..41e3fd4d57b 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/types.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <type_traits>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     static_assert((std::is_same<std::char_traits<char16_t>::char_type, char16_t>::value), "");
@@ -29,4 +29,6 @@ int main()
     static_assert((std::is_same<std::char_traits<char16_t>::pos_type, std::u16streampos>::value), "");
     static_assert((std::is_same<std::char_traits<char16_t>::state_type, std::mbstate_t>::value), "");
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign2.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign2.pass.cpp
index 90388aa43f8..f77d54f7916 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign2.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign2.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -40,4 +40,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign3.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign3.pass.cpp
index af69fdcfa2a..26985481c1f 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign3.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/assign3.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char32_t s2[3] = {0};
@@ -25,4 +25,6 @@ int main()
     assert(s2[2] == char32_t(5));
     assert(std::char_traits<char32_t>::assign(NULL, 0, char32_t(5)) == NULL);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/compare.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/compare.pass.cpp
index 5d1cfa84248..f2dd01ac9aa 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/compare.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/compare.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -57,4 +57,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/copy.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/copy.pass.cpp
index d9f983b5bd6..8b2d6ce9074 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/copy.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/copy.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char32_t s1[] = {1, 2, 3};
@@ -27,4 +27,6 @@ int main()
     assert(std::char_traits<char32_t>::copy(NULL, s1, 0) == NULL);
     assert(std::char_traits<char32_t>::copy(s1, NULL, 0) == s1);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp
index ac042907ab8..5c28f47bb48 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp
@@ -15,10 +15,12 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     std::char_traits<char32_t>::int_type i = std::char_traits<char32_t>::eof();
     ((void)i); // Prevent unused warning
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp
index aef7ebb703d..516f38bd087 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -25,4 +25,6 @@ int main()
     assert(!std::char_traits<char32_t>::eq(U'a', U'A'));
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq_int_type.pass.cpp
index 91b2fb0fbad..5d241159f72 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq_int_type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -28,4 +28,6 @@ int main()
     assert( std::char_traits<char32_t>::eq_int_type(std::char_traits<char32_t>::eof(),
                                                     std::char_traits<char32_t>::eof()));
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/find.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/find.pass.cpp
index ac1723a6535..5a89596dee9 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/find.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/find.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char32_t s1[] = {1, 2, 3};
@@ -44,4 +44,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/length.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/length.pass.cpp
index c4c01ddf1a4..ef2ea3419bd 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/length.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/length.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -41,4 +41,6 @@ int main()
     static_assert(test_constexpr(), "" );
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp
index d3fe9a4516e..51c1faf9ef2 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -25,4 +25,6 @@ int main()
     assert( std::char_traits<char32_t>::lt(U'A', U'a'));
 #endif
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/move.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/move.pass.cpp
index 0ac49d0c9c3..7cda99bd830 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/move.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/move.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     char32_t s1[] = {1, 2, 3};
@@ -31,4 +31,6 @@ int main()
     assert(std::char_traits<char32_t>::move(NULL, s1, 0) == NULL);
     assert(std::char_traits<char32_t>::move(s1, NULL, 0) == s1);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/not_eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/not_eof.pass.cpp
index dbe1dfe8b30..aeba1228e6f 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/not_eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/not_eof.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -28,4 +28,6 @@ int main()
     assert(std::char_traits<char32_t>::not_eof(std::char_traits<char32_t>::eof()) !=
            std::char_traits<char32_t>::eof());
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_char_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_char_type.pass.cpp
index 1c16a55b811..75104e7bf16 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_char_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_char_type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -26,4 +26,6 @@ int main()
 #endif
     assert(std::char_traits<char32_t>::to_char_type(0) == 0);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_int_type.pass.cpp
index 4ec9a9b631f..8299e94dabd 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/to_int_type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
@@ -26,4 +26,6 @@ int main()
 #endif
     assert(std::char_traits<char32_t>::to_int_type(0) == 0);
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/types.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/types.pass.cpp
index 65624dd5efd..5ec558f5470 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/types.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/types.pass.cpp
@@ -20,7 +20,7 @@
 #include <type_traits>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     static_assert((std::is_same<std::char_traits<char32_t>::char_type, char32_t>::value), "");
@@ -29,4 +29,6 @@ int main()
     static_assert((std::is_same<std::char_traits<char32_t>::pos_type, std::u32streampos>::value), "");
     static_assert((std::is_same<std::char_traits<char32_t>::state_type, std::mbstate_t>::value), "");
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign2.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign2.pass.cpp
index b14662d09be..c669ab9c1a6 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign2.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign2.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool test_constexpr()
     return c == u'a';
 }
 
-int main()
+int main(int, char**)
 {
     char8_t c = u8'\0';
     std::char_traits<char8_t>::assign(c, u8'a');
@@ -34,5 +34,7 @@ int main()
     static_assert(test_constexpr(), "");
 }
 #else
-int main () {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign3.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign3.pass.cpp
index eae7c82ba86..f9c176e9b2f 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign3.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/assign3.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     char8_t s2[3] = {0};
@@ -26,4 +26,6 @@ int main()
     assert(s2[2] == char8_t(5));
     assert(std::char_traits<char8_t>::assign(NULL, 0, char8_t(5)) == NULL);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp
index 0ac815b9b17..063ab5dc516 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char8_t>::compare(u8"", u8"", 0) == 0);
     assert(std::char_traits<char8_t>::compare(NULL, NULL, 0) == 0);
@@ -53,5 +53,7 @@ int main()
     static_assert(test_constexpr(), "" );
 }
 #else
-int main () {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/copy.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/copy.pass.cpp
index 2f091029b06..7bf949197a8 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/copy.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/copy.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     char8_t s1[] = {1, 2, 3};
@@ -28,4 +28,6 @@ int main()
     assert(std::char_traits<char8_t>::copy(NULL, s1, 0) == NULL);
     assert(std::char_traits<char8_t>::copy(s1, NULL, 0) == s1);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eof.pass.cpp
index 9d13d7dd0a6..e112556886d 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eof.pass.cpp
@@ -16,10 +16,12 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     std::char_traits<char8_t>::int_type i = std::char_traits<char8_t>::eof();
     ((void)i); // Prevent unused warning
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq.pass.cpp
index 4d334110f36..6e32c85bbe3 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq.pass.cpp
@@ -18,10 +18,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     assert( std::char_traits<char8_t>::eq(u8'a', u8'a'));
     assert(!std::char_traits<char8_t>::eq(u8'a', u8'A'));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq_int_type.pass.cpp
index 6cc58eba1db..8c5e1971747 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/eq_int_type.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     assert( std::char_traits<char8_t>::eq_int_type(u8'a', u8'a'));
@@ -27,4 +27,6 @@ int main()
     assert( std::char_traits<char8_t>::eq_int_type(std::char_traits<char8_t>::eof(),
                                                     std::char_traits<char8_t>::eof()));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/find.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/find.pass.cpp
index 9d2e62e348c..170539e0694 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/find.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/find.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool test_constexpr()
         && std::char_traits<char8_t>::find(p, 3, u8'4') == nullptr;
 }
 
-int main()
+int main(int, char**)
 {
     char8_t s1[] = {1, 2, 3};
     assert(std::char_traits<char8_t>::find(s1, 3, char8_t(1)) == s1);
@@ -41,5 +41,7 @@ int main()
     static_assert(test_constexpr(), "" );
 }
 #else
-int main () {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/length.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/length.pass.cpp
index 10f800127b6..ce2c717cc57 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/length.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/length.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool test_constexpr()
         && std::char_traits<char8_t>::length(u8"abcd") == 4;
 }
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<char8_t>::length(u8"") == 0);
     assert(std::char_traits<char8_t>::length(u8"a") == 1);
@@ -36,5 +36,7 @@ int main()
     static_assert(test_constexpr(), "");
 }
 #else
-int main() { }
+int main(int, char**) { 
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/lt.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/lt.pass.cpp
index 4653007bf72..a4fb1251203 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/lt.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/lt.pass.cpp
@@ -18,10 +18,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     assert(!std::char_traits<char8_t>::lt(u8'a', u8'a'));
     assert( std::char_traits<char8_t>::lt(u8'A', u8'a'));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/move.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/move.pass.cpp
index 5ca536966cd..a5e1359dd4d 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/move.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/move.pass.cpp
@@ -16,7 +16,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     char8_t s1[] = {1, 2, 3};
@@ -32,4 +32,6 @@ int main()
     assert(std::char_traits<char8_t>::move(NULL, s1, 0) == NULL);
     assert(std::char_traits<char8_t>::move(s1, NULL, 0) == s1);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/not_eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/not_eof.pass.cpp
index 69e8ddac8cc..3d1141d72d7 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/not_eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/not_eof.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     assert(std::char_traits<char8_t>::not_eof(u8'a') == u8'a');
@@ -27,4 +27,6 @@ int main()
     assert(std::char_traits<char8_t>::not_eof(std::char_traits<char8_t>::eof()) !=
            std::char_traits<char8_t>::eof());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_char_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_char_type.pass.cpp
index 0b021d28340..4edc49452ef 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_char_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_char_type.pass.cpp
@@ -18,11 +18,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     assert(std::char_traits<char8_t>::to_char_type(u8'a') == u8'a');
     assert(std::char_traits<char8_t>::to_char_type(u8'A') == u8'A');
     assert(std::char_traits<char8_t>::to_char_type(0) == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_int_type.pass.cpp
index 98974ab86b1..ab3c9dc7993 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/to_int_type.pass.cpp
@@ -18,11 +18,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     assert(std::char_traits<char8_t>::to_int_type(u8'a') == u8'a');
     assert(std::char_traits<char8_t>::to_int_type(u8'A') == u8'A');
     assert(std::char_traits<char8_t>::to_int_type(0) == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/types.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/types.pass.cpp
index cfb20faaf75..245dcd87d99 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/types.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     static_assert((std::is_same<std::char_traits<char8_t>::char_type,  char8_t>::value), "");
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<std::char_traits<char8_t>::pos_type,   std::u16streampos>::value), "");
     static_assert((std::is_same<std::char_traits<char8_t>::state_type, std::mbstate_t>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign2.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign2.pass.cpp
index 9b9b0ea491c..25e42701448 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign2.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign2.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     wchar_t c = L'\0';
     std::char_traits<wchar_t>::assign(c, L'a');
@@ -36,4 +36,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign3.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign3.pass.cpp
index 42df4081d50..d4ed4340945 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign3.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/assign3.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     wchar_t s2[3] = {0};
     assert(std::char_traits<wchar_t>::assign(s2, 3, wchar_t(5)) == s2);
@@ -23,4 +23,6 @@ int main()
     assert(s2[1] == wchar_t(5));
     assert(s2[2] == wchar_t(5));
     assert(std::char_traits<wchar_t>::assign(NULL, 0, wchar_t(5)) == NULL);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/compare.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/compare.pass.cpp
index d6272f39357..1c2e11912f8 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/compare.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/compare.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::compare(L"", L"", 0) == 0);
     assert(std::char_traits<wchar_t>::compare(NULL, NULL, 0) == 0);
@@ -53,4 +53,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/copy.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/copy.pass.cpp
index f90688a9aac..309c21316c4 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/copy.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/copy.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     wchar_t s1[] = {1, 2, 3};
     wchar_t s2[3] = {0};
@@ -25,4 +25,6 @@ int main()
     assert(s2[2] == wchar_t(3));
     assert(std::char_traits<wchar_t>::copy(NULL, s1, 0) == NULL);
     assert(std::char_traits<wchar_t>::copy(s1, NULL, 0) == s1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eof.pass.cpp
index 9b466a5f0cc..6190220fe90 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eof.pass.cpp
@@ -15,7 +15,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::eof() == WEOF);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp
index a89a0002da7..701a6502fc6 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp
@@ -15,8 +15,10 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::eq(L'a', L'a'));
     assert(!std::char_traits<wchar_t>::eq(L'a', L'A'));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq_int_type.pass.cpp
index e7e8285ca0f..b218186b43f 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq_int_type.pass.cpp
@@ -15,11 +15,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert( std::char_traits<wchar_t>::eq_int_type(L'a', L'a'));
     assert(!std::char_traits<wchar_t>::eq_int_type(L'a', L'A'));
     assert(!std::char_traits<wchar_t>::eq_int_type(std::char_traits<wchar_t>::eof(), L'A'));
     assert( std::char_traits<wchar_t>::eq_int_type(std::char_traits<wchar_t>::eof(),
                                                    std::char_traits<wchar_t>::eof()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/find.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/find.pass.cpp
index ed59397cc2c..78a9ad5c3f9 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/find.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/find.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     wchar_t s1[] = {1, 2, 3};
     assert(std::char_traits<wchar_t>::find(s1, 3, wchar_t(1)) == s1);
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/length.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/length.pass.cpp
index a9176c8d459..742189205ab 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/length.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/length.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::length(L"") == 0);
     assert(std::char_traits<wchar_t>::length(L"a") == 1);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp
index f7950b782bb..9abd9cf59d7 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp
@@ -15,8 +15,10 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(!std::char_traits<wchar_t>::lt(L'a', L'a'));
     assert( std::char_traits<wchar_t>::lt(L'A', L'a'));
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/move.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/move.pass.cpp
index d833bc0b5b2..341a90233a8 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/move.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/move.pass.cpp
@@ -15,7 +15,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     wchar_t s1[] = {1, 2, 3};
     assert(std::char_traits<wchar_t>::move(s1, s1+1, 2) == s1);
@@ -29,4 +29,6 @@ int main()
     assert(s1[2] == wchar_t(3));
     assert(std::char_traits<wchar_t>::move(NULL, s1, 0) == NULL);
     assert(std::char_traits<wchar_t>::move(s1, NULL, 0) == s1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/not_eof.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/not_eof.pass.cpp
index 751903beae4..92f08b1d520 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/not_eof.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/not_eof.pass.cpp
@@ -15,11 +15,13 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::not_eof(L'a') == L'a');
     assert(std::char_traits<wchar_t>::not_eof(L'A') == L'A');
     assert(std::char_traits<wchar_t>::not_eof(0) == 0);
     assert(std::char_traits<wchar_t>::not_eof(std::char_traits<wchar_t>::eof()) !=
            std::char_traits<wchar_t>::eof());
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_char_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_char_type.pass.cpp
index 7654c32873f..f479bec9daf 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_char_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_char_type.pass.cpp
@@ -15,9 +15,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::to_char_type(L'a') == L'a');
     assert(std::char_traits<wchar_t>::to_char_type(L'A') == L'A');
     assert(std::char_traits<wchar_t>::to_char_type(0) == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_int_type.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_int_type.pass.cpp
index a003bdc1115..11fe2419b1a 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_int_type.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/to_int_type.pass.cpp
@@ -15,9 +15,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::char_traits<wchar_t>::to_int_type(L'a') == L'a');
     assert(std::char_traits<wchar_t>::to_int_type(L'A') == L'A');
     assert(std::char_traits<wchar_t>::to_int_type(0) == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/types.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/types.pass.cpp
index c367be47ef3..9781d55e392 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/types.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/types.pass.cpp
@@ -19,11 +19,13 @@
 #include <string>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::char_traits<wchar_t>::char_type, wchar_t>::value), "");
     static_assert((std::is_same<std::char_traits<wchar_t>::int_type, std::wint_t>::value), "");
     static_assert((std::is_same<std::char_traits<wchar_t>::off_type, std::streamoff>::value), "");
     static_assert((std::is_same<std::char_traits<wchar_t>::pos_type, std::wstreampos>::value), "");
     static_assert((std::is_same<std::char_traits<wchar_t>::state_type, std::mbstate_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.specializations/nothing_to_do.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.specializations/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.specializations/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.specializations/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/char.traits.typedefs/nothing_to_do.pass.cpp b/libcxx/test/std/strings/char.traits/char.traits.typedefs/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/char.traits/char.traits.typedefs/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/char.traits.typedefs/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/char.traits/nothing_to_do.pass.cpp b/libcxx/test/std/strings/char.traits/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/strings/char.traits/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/char.traits/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.classes/typedefs.pass.cpp b/libcxx/test/std/strings/string.classes/typedefs.pass.cpp
index 14fe3887705..cbc028391b5 100644
--- a/libcxx/test/std/strings/string.classes/typedefs.pass.cpp
+++ b/libcxx/test/std/strings/string.classes/typedefs.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::string, std::basic_string<char> >::value), "");
     static_assert((std::is_same<std::wstring, std::basic_string<wchar_t> >::value), "");
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<std::u16string, std::basic_string<char16_t> >::value), "");
     static_assert((std::is_same<std::u32string, std::basic_string<char32_t> >::value), "");
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stod.pass.cpp b/libcxx/test/std/strings/string.conversions/stod.pass.cpp
index 9909497e696..d13b695f21c 100644
--- a/libcxx/test/std/strings/string.conversions/stod.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stod.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stod("0") == 0);
     assert(std::stod(L"0") == 0);
@@ -185,4 +185,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stof.pass.cpp b/libcxx/test/std/strings/string.conversions/stof.pass.cpp
index 8e7f4b4ecfc..2c8e4c9b927 100644
--- a/libcxx/test/std/strings/string.conversions/stof.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stof.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stof("0") == 0);
     assert(std::stof(L"0") == 0);
@@ -186,4 +186,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stoi.pass.cpp b/libcxx/test/std/strings/string.conversions/stoi.pass.cpp
index 36998336c2e..b3e41633126 100644
--- a/libcxx/test/std/strings/string.conversions/stoi.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stoi.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stoi("0") == 0);
     assert(std::stoi(L"0") == 0);
@@ -109,4 +109,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stol.pass.cpp b/libcxx/test/std/strings/string.conversions/stol.pass.cpp
index 8e18a0088ca..ef0cbb4ed3c 100644
--- a/libcxx/test/std/strings/string.conversions/stol.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stol.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stol("0") == 0);
     assert(std::stol(L"0") == 0);
@@ -113,4 +113,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stold.pass.cpp b/libcxx/test/std/strings/string.conversions/stold.pass.cpp
index 4677bd7d2eb..5b21fd0e345 100644
--- a/libcxx/test/std/strings/string.conversions/stold.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stold.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stold("0") == 0);
     assert(std::stold(L"0") == 0);
@@ -188,4 +188,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stoll.pass.cpp b/libcxx/test/std/strings/string.conversions/stoll.pass.cpp
index f8a5a6b0e0f..73d5e82015f 100644
--- a/libcxx/test/std/strings/string.conversions/stoll.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stoll.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stoll("0") == 0);
     assert(std::stoll(L"0") == 0);
@@ -112,4 +112,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stoul.pass.cpp b/libcxx/test/std/strings/string.conversions/stoul.pass.cpp
index e60a6a071ad..6ef861396cd 100644
--- a/libcxx/test/std/strings/string.conversions/stoul.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stoul.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stoul("0") == 0);
     assert(std::stoul(L"0") == 0);
@@ -111,4 +111,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/stoull.pass.cpp b/libcxx/test/std/strings/string.conversions/stoull.pass.cpp
index 32369664d08..3e21c683af4 100644
--- a/libcxx/test/std/strings/string.conversions/stoull.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/stoull.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::stoull("0") == 0);
     assert(std::stoull(L"0") == 0);
@@ -112,4 +112,6 @@ int main()
         assert(idx == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/to_string.pass.cpp b/libcxx/test/std/strings/string.conversions/to_string.pass.cpp
index 864425134e0..23729cd4f49 100644
--- a/libcxx/test/std/strings/string.conversions/to_string.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/to_string.pass.cpp
@@ -112,7 +112,7 @@ test_float()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_signed<int>();
     test_signed<long>();
@@ -123,4 +123,6 @@ int main()
     test_float<float>();
     test_float<double>();
     test_float<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.conversions/to_wstring.pass.cpp b/libcxx/test/std/strings/string.conversions/to_wstring.pass.cpp
index 82c3f617b9e..02a262a0f29 100644
--- a/libcxx/test/std/strings/string.conversions/to_wstring.pass.cpp
+++ b/libcxx/test/std/strings/string.conversions/to_wstring.pass.cpp
@@ -112,7 +112,7 @@ test_float()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_signed<int>();
     test_signed<long>();
@@ -123,4 +123,6 @@ int main()
     test_float<float>();
     test_float<double>();
     test_float<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/char.bad.fail.cpp b/libcxx/test/std/strings/string.view/char.bad.fail.cpp
index 3d04cd085c5..522466613ca 100644
--- a/libcxx/test/std/strings/string.view/char.bad.fail.cpp
+++ b/libcxx/test/std/strings/string.view/char.bad.fail.cpp
@@ -26,7 +26,7 @@ private:
     int two;
 };
 
-int main()
+int main(int, char**)
 {
     {
 //  array
@@ -49,4 +49,6 @@ int main()
     std::basic_string_view<NotStandardLayout, test_traits<NotStandardLayout> > sv;
 //  expected-error-re@string_view:* {{static_assert failed{{.*}} "Character type of basic_string_view must be standard-layout"}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.access/at.pass.cpp b/libcxx/test/std/strings/string.view/string.view.access/at.pass.cpp
index b4b2667bbe2..3d741c33ffb 100644
--- a/libcxx/test/std/strings/string.view/string.view.access/at.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.access/at.pass.cpp
@@ -36,7 +36,7 @@ void test ( const CharT *s, size_t len ) {
 #endif
 }
 
-int main () {
+int main(int, char**) {
     test ( "ABCDE", 5 );
     test ( "a", 1 );
 
@@ -59,4 +59,6 @@ int main () {
     static_assert ( sv.at(1) == 'B', "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.access/back.pass.cpp b/libcxx/test/std/strings/string.view/string.view.access/back.pass.cpp
index 8c8fd420d79..4505f1cf981 100644
--- a/libcxx/test/std/strings/string.view/string.view.access/back.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.access/back.pass.cpp
@@ -24,7 +24,7 @@ bool test ( const CharT *s, size_t len ) {
     return &sv.back() == s + len - 1;
     }
 
-int main () {
+int main(int, char**) {
     assert ( test ( "ABCDE", 5 ));
     assert ( test ( "a", 1 ));
 
@@ -46,4 +46,6 @@ int main () {
     static_assert ( sv.back()  == 'B', "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp b/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp
index 85e02ceb0a7..9ab83dfb2f5 100644
--- a/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp
@@ -27,7 +27,7 @@ void test ( const CharT *s, size_t len ) {
 #endif
     }
 
-int main () {
+int main(int, char**) {
     test ( "ABCDE", 5 );
     test ( "a", 1 );
 
@@ -50,4 +50,6 @@ int main () {
     static_assert( sv.data() == s, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.access/front.pass.cpp b/libcxx/test/std/strings/string.view/string.view.access/front.pass.cpp
index 6e73202d676..554ed1bab12 100644
--- a/libcxx/test/std/strings/string.view/string.view.access/front.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.access/front.pass.cpp
@@ -24,7 +24,7 @@ bool test ( const CharT *s, size_t len ) {
     return &sv.front() == s;
     }
 
-int main () {
+int main(int, char**) {
     assert ( test ( "ABCDE", 5 ));
     assert ( test ( "a", 1 ));
 
@@ -46,4 +46,6 @@ int main () {
     static_assert ( sv.front()  == 'A', "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.access/index.pass.cpp b/libcxx/test/std/strings/string.view/string.view.access/index.pass.cpp
index 87598dffe73..33992de7c05 100644
--- a/libcxx/test/std/strings/string.view/string.view.access/index.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.access/index.pass.cpp
@@ -26,7 +26,7 @@ void test ( const CharT *s, size_t len ) {
         }
     }
 
-int main () {
+int main(int, char**) {
     test ( "ABCDE", 5 );
     test ( "a", 1 );
 
@@ -49,4 +49,6 @@ int main () {
     static_assert ( sv[1]  == 'B', "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp b/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp
index 93cc762832f..025d905a333 100644
--- a/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp
@@ -62,7 +62,7 @@ void test2 ( const CharT *s, size_t len ) {
     }
 }
 
-int main () {
+int main(int, char**) {
     test1<std::string_view> ();
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
     test1<std::u8string_view> ();
@@ -99,4 +99,6 @@ int main () {
     test2 ( U"a", 1 );
     test2 ( U"", 0 );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.capacity/empty.fail.cpp b/libcxx/test/std/strings/string.view/string.view.capacity/empty.fail.cpp
index 74bd413020d..1dd1dcf7cb5 100644
--- a/libcxx/test/std/strings/string.view/string.view.capacity/empty.fail.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.capacity/empty.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::string_view c;
     c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.pointer.pass.cpp
index bb6c3431652..e771bd328a9 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.pointer.pass.cpp
@@ -27,7 +27,7 @@ test(S lhs, const typename S::value_type* rhs, bool x)
     assert((rhs == lhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -65,4 +65,6 @@ int main()
     static_assert (!("abcde0" == sv2), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string.pass.cpp
index bb142b0b3c3..d27d4c44588 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string.pass.cpp
@@ -25,7 +25,7 @@ test(const std::string &lhs, S rhs, bool x)
     assert((rhs == lhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -46,5 +46,7 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
     }
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string_view.pass.cpp
index d7b113c120b..259711e3c52 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opeq.string_view.string_view.pass.cpp
@@ -26,7 +26,7 @@ test(S lhs, S rhs, bool x)
     assert((rhs == lhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -58,4 +58,6 @@ int main()
     static_assert (!(sv1 == sv3), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.pointer.pass.cpp
index 4f32425dc49..5fa57eb394c 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.pointer.pass.cpp
@@ -27,7 +27,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x, bool y)
     assert((rhs >= lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -68,4 +68,6 @@ int main()
     static_assert (  "abcde0" >= sv2, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string.pass.cpp
index 9cbe389cd48..dddaa390ed3 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string.pass.cpp
@@ -25,7 +25,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x, bool y)
     assert((rhs >= lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -46,4 +46,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true, false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true, true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string_view.pass.cpp
index 81fee1f3953..d35bea575c8 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opge.string_view.string_view.pass.cpp
@@ -26,7 +26,7 @@ test(const S& lhs, const S& rhs, bool x, bool y)
     assert((rhs >= lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -61,4 +61,6 @@ int main()
     static_assert (  sv2 >= sv1,  "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.pointer.pass.cpp
index c295645a9b7..80dcc7b497b 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.pointer.pass.cpp
@@ -27,7 +27,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x, bool y)
     assert((rhs > lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -68,4 +68,6 @@ int main()
     static_assert (  "abcde0" > sv2, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string.pass.cpp
index b07b6a7aca2..84c9478bfc5 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string.pass.cpp
@@ -25,7 +25,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x, bool y)
     assert((rhs > lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -46,4 +46,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true, false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false, false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string_view.pass.cpp
index 984f2c6a32e..ec31d5c2c1d 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opgt.string_view.string_view.pass.cpp
@@ -26,7 +26,7 @@ test(const S& lhs, const S& rhs, bool x, bool y)
     assert((rhs > lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -61,4 +61,6 @@ int main()
     static_assert (  sv2 > sv1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.pointer.pass.cpp
index 81d0d167a00..4f582239a83 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.pointer.pass.cpp
@@ -27,7 +27,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x, bool y)
     assert((rhs <= lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -68,4 +68,6 @@ int main()
     static_assert (!("abcde0" <= sv2), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string.pass.cpp
index 3cdb0215e48..80e80757bf9 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string.pass.cpp
@@ -25,7 +25,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x, bool y)
     assert((rhs <= lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -46,4 +46,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false, true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true, true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string_view.pass.cpp
index 3ec0222f66f..b1c18612425 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/ople.string_view.string_view.pass.cpp
@@ -26,7 +26,7 @@ test(const S& lhs, const S& rhs, bool x, bool y)
     assert((rhs <= lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -61,4 +61,6 @@ int main()
     static_assert (!(sv2 <= sv1), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.pointer.pass.cpp
index f8093c86a73..14bba2abfe6 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.pointer.pass.cpp
@@ -27,7 +27,7 @@ test(const typename S::value_type* lhs, const S& rhs, bool x, bool y)
     assert((rhs < lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -68,4 +68,6 @@ int main()
     static_assert (!("abcde0" < sv2), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string.pass.cpp
index e7341f17d1f..f611bac7a84 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string.pass.cpp
@@ -25,7 +25,7 @@ test(const S& lhs, const typename S::value_type* rhs, bool x, bool y)
     assert((rhs < lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -46,4 +46,6 @@ int main()
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false, true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false, false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string_view.pass.cpp
index a7e51f9af8c..f44e373619a 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/oplt.string_view.string_view.pass.cpp
@@ -26,7 +26,7 @@ test(const S& lhs, const S& rhs, bool x, bool y)
     assert((rhs < lhs) == y);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -61,4 +61,6 @@ int main()
     static_assert (!(sv2 < sv1), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.pointer.pass.cpp
index 1531626a884..6b8add83146 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.pointer.pass.cpp
@@ -27,7 +27,7 @@ test(S lhs, const typename S::value_type* rhs, bool x)
     assert((rhs != lhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -66,4 +66,6 @@ int main()
     static_assert (  "abcde0" != sv2, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string.pass.cpp
index 8e5539a8079..613eaf7b32f 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string.pass.cpp
@@ -25,7 +25,7 @@ test(const std::string &lhs, S rhs, bool x)
     assert((rhs != lhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -46,4 +46,6 @@ int main()
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string_view.pass.cpp
index 0e01e94db43..90d153335ff 100644
--- a/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.comparison/opne.string_view.string_view.pass.cpp
@@ -26,7 +26,7 @@ test(S lhs, S rhs, bool x)
     assert((rhs != lhs) == x);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -58,4 +58,6 @@ int main()
     static_assert (   sv1 != sv3,  "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/assign.pass.cpp b/libcxx/test/std/strings/string.view/string.view.cons/assign.pass.cpp
index 8247c53c739..b2bf8ed7198 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/assign.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/assign.pass.cpp
@@ -29,7 +29,7 @@ bool test (T sv0)
     return sv0.size() == sv1.size() && sv0.data() == sv1.data();
     }
 
-int main () {
+int main(int, char**) {
 
     assert( test<std::string_view>    (  "1234"));
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -54,4 +54,6 @@ int main () {
 #endif
     static_assert( test<std::wstring_view>   ({ L"abc", 3}), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/default.pass.cpp b/libcxx/test/std/strings/string.view/string.view.cons/default.pass.cpp
index fe1fa974012..07a453b2369 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/default.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/default.pass.cpp
@@ -35,7 +35,7 @@ void test () {
     }
 }
 
-int main () {
+int main(int, char**) {
     test<std::string_view> ();
     test<std::u16string_view> ();
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -44,4 +44,6 @@ int main () {
     test<std::u32string_view> ();
     test<std::wstring_view> ();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/from_literal.pass.cpp b/libcxx/test/std/strings/string.view/string.view.cons/from_literal.pass.cpp
index 7430f4ad6b5..bcd83da74c6 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/from_literal.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/from_literal.pass.cpp
@@ -39,7 +39,7 @@ void test ( const CharT *s ) {
     }
 
 
-int main () {
+int main(int, char**) {
 
     test ( "QBCDE" );
     test ( "A" );
@@ -65,4 +65,6 @@ int main () {
     static_assert ( sv1.size() == 5, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/from_ptr_len.pass.cpp b/libcxx/test/std/strings/string.view/string.view.cons/from_ptr_len.pass.cpp
index 8ad0449aaca..92ae675a399 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/from_ptr_len.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/from_ptr_len.pass.cpp
@@ -31,7 +31,7 @@ void test ( const CharT *s, size_t sz ) {
     }
 }
 
-int main () {
+int main(int, char**) {
 
     test ( "QBCDE", 5 );
     test ( "QBCDE", 2 );
@@ -82,4 +82,6 @@ int main () {
     }
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/from_string.pass.cpp b/libcxx/test/std/strings/string.view/string.view.cons/from_string.pass.cpp
index 5e4a2d31908..2043d662a7a 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/from_string.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/from_string.pass.cpp
@@ -31,7 +31,7 @@ void test ( const std::basic_string<CharT, Traits> &str ) {
     assert ( sv1.data() == str.data());
 }
 
-int main () {
+int main(int, char**) {
 
     test ( std::string("QBCDE") );
     test ( std::string("") );
@@ -61,4 +61,6 @@ int main () {
     test ( std::basic_string<char, dummy_char_traits>("") );
     test ( std::basic_string<char, dummy_char_traits>() );
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/from_string1.fail.cpp b/libcxx/test/std/strings/string.view/string.view.cons/from_string1.fail.cpp
index 343600625e8..3c464d7fe3e 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/from_string1.fail.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/from_string1.fail.cpp
@@ -18,7 +18,7 @@
 
 struct dummy_char_traits : public std::char_traits<char> {};
 
-int main () {
+int main(int, char**) {
     using string_view = std::basic_string_view<char>;
     using string      = std::              basic_string     <char, dummy_char_traits>;
 
@@ -28,4 +28,6 @@ int main () {
     assert ( sv1.size() == s.size());
     assert ( sv1.data() == s.data());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/from_string2.fail.cpp b/libcxx/test/std/strings/string.view/string.view.cons/from_string2.fail.cpp
index 2a0544defea..482d220013b 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/from_string2.fail.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/from_string2.fail.cpp
@@ -18,7 +18,7 @@
 
 struct dummy_char_traits : public std::char_traits<char> {};
 
-int main () {
+int main(int, char**) {
     using string_view = std::basic_string_view<char, dummy_char_traits>;
     using string      = std::              basic_string     <char>;
 
@@ -28,4 +28,6 @@ int main () {
     assert ( sv1.size() == s.size());
     assert ( sv1.data() == s.data());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.cons/implicit_deduction_guides.pass.cpp b/libcxx/test/std/strings/string.view/string.view.cons/implicit_deduction_guides.pass.cpp
index 3f1f562a475..b95dca63dfd 100644
--- a/libcxx/test/std/strings/string.view/string.view.cons/implicit_deduction_guides.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.cons/implicit_deduction_guides.pass.cpp
@@ -26,7 +26,7 @@
 // (2)  basic_string_view(const basic_string_view&)
 // (3)  basic_string_view(const CharT*, size_type)
 // (4)  basic_string_view(const CharT*)
-int main()
+int main(int, char**)
 {
   { // Testing (1)
     // Nothing TODO. Cannot deduce without any arguments.
@@ -61,4 +61,6 @@ int main()
     ASSERT_SAME_TYPE(decltype(w), std::wstring_view);
     assert(w == L"abcdef");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_char_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_char_size.pass.cpp
index 8898d11afbf..82173a93a88 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_char_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_char_size.pass.cpp
@@ -35,7 +35,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(0 <= x && x + 1 <= s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -81,4 +81,6 @@ int main()
     static_assert (sv2.find( 'c', 4 ) == SV::npos, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_char_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_char_size.pass.cpp
index aae4048ac52..4566adabfd3 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_char_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_char_size.pass.cpp
@@ -35,7 +35,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -81,4 +81,6 @@ int main()
     static_assert (sv2.find_first_not_of( 'q', 5 ) == SV::npos, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size.pass.cpp
index 0020e60b801..17c3c5293f0 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size.pass.cpp
@@ -141,7 +141,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -162,4 +162,6 @@ int main()
     static_assert (sv2.find_first_not_of( "lecar", 0) == 1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size_size.pass.cpp
index 52f06967693..707a7a96439 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_pointer_size_size.pass.cpp
@@ -366,7 +366,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -389,4 +389,6 @@ int main()
     static_assert (sv2.find_first_not_of( "lecar", 0, 5) == 1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_string_view_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_string_view_size.pass.cpp
index 9378c6a0f45..37445b578c7 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_not_of_string_view_size.pass.cpp
@@ -137,11 +137,13 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
     test0<S>();
     test1<S>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_char_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_char_size.pass.cpp
index 6be6ddcd99c..d4916bec32f 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_char_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_char_size.pass.cpp
@@ -35,7 +35,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -79,4 +79,6 @@ int main()
     static_assert (sv2.find_first_of( 'e', 5 ) == SV::npos, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size.pass.cpp
index bc3ea554bde..7e43109afdd 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size.pass.cpp
@@ -141,7 +141,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -162,4 +162,6 @@ int main()
     static_assert (sv2.find_first_of( "lecar", 0) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size_size.pass.cpp
index cd978436eb5..165fb2362ae 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_pointer_size_size.pass.cpp
@@ -366,7 +366,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -389,4 +389,6 @@ int main()
     static_assert (sv2.find_first_of( "lecar", 0, 5) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_string_view_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_string_view_size.pass.cpp
index 545f4e51508..c705f0266d8 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_first_of_string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_first_of_string_view_size.pass.cpp
@@ -137,11 +137,13 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
     test0<S>();
     test1<S>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_char_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_char_size.pass.cpp
index 8d80557d4c5..0b6e6cfb0fa 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_char_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_char_size.pass.cpp
@@ -35,7 +35,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -79,4 +79,6 @@ int main()
     static_assert (sv2.find_last_not_of( 'e', 5 ) == 3, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size.pass.cpp
index f7daf3fa3bd..fe17b779dd9 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size.pass.cpp
@@ -141,7 +141,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -162,4 +162,6 @@ int main()
     static_assert (sv2.find_last_not_of( "lecar", 5) == 3, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size_size.pass.cpp
index 8fd25539525..11a5c27e8da 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_pointer_size_size.pass.cpp
@@ -366,7 +366,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -389,4 +389,6 @@ int main()
     static_assert (sv2.find_last_not_of( "lecar", 5, 0) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_string_view_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_string_view_size.pass.cpp
index 06a31a1d661..e90e38c0d70 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_not_of_string_view_size.pass.cpp
@@ -137,11 +137,13 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
     test0<S>();
     test1<S>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_char_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_char_size.pass.cpp
index 147e191b237..fdcf3173671 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_char_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_char_size.pass.cpp
@@ -35,7 +35,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x < s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -79,4 +79,6 @@ int main()
     static_assert (sv2.find_last_of( 'e', 5 ) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size.pass.cpp
index 5a12718314c..640f4837596 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size.pass.cpp
@@ -141,7 +141,7 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), "htaobedqikfplcgjsmrn", 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -162,4 +162,6 @@ int main()
     static_assert (sv2.find_last_of( "lecar", 5) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size_size.pass.cpp
index 98402982691..e82c935b5ff 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_pointer_size_size.pass.cpp
@@ -366,7 +366,7 @@ void test3()
     test(S("hnbrcplsjfgiktoedmaq"), "qprlsfojamgndekthibc", 21, 20, 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -389,4 +389,6 @@ int main()
     static_assert (sv2.find_last_of( "lecar", 5, 5) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_string_view_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_string_view_size.pass.cpp
index 84b5a96df5d..02c1184eec8 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_last_of_string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_last_of_string_view_size.pass.cpp
@@ -137,11 +137,13 @@ void test1()
     test(S("pniotcfrhqsmgdkjbael"), S("htaobedqikfplcgjsmrn"), 19);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
     test0<S>();
     test1<S>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size.pass.cpp
index 2be32a46a95..3f4fee54ef4 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size.pass.cpp
@@ -147,7 +147,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -168,4 +168,6 @@ int main()
     static_assert (sv2.find( "abcde", 1) == SV::npos, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size_size.pass.cpp
index 0f7d295a4a5..74caa6fea7b 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_pointer_size_size.pass.cpp
@@ -366,7 +366,7 @@ void test3()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 20, S::npos);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -390,4 +390,6 @@ int main()
     static_assert (sv2.find( "abcde", 0, 1 ) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/find_string_view_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/find_string_view_size.pass.cpp
index 0a5cec54eda..ed3b7c11c02 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/find_string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/find_string_view_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), S("abcdeabcdeabcdeabcde"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -161,4 +161,6 @@ int main()
     static_assert (sv2.find(sv2, 1 ) == SV::npos, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/rfind_char_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/rfind_char_size.pass.cpp
index 62f50ed8786..959bb05f871 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/rfind_char_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/rfind_char_size.pass.cpp
@@ -34,7 +34,7 @@ test(const S& s, typename S::value_type c, typename S::size_type x)
         assert(x + 1 <= s.size());
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -80,4 +80,6 @@ int main()
     static_assert (sv2.rfind( 'b', 4 ) == 1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size.pass.cpp
index 0ff2be51fc1..6010083ab14 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size.pass.cpp
@@ -147,7 +147,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -168,4 +168,6 @@ int main()
     static_assert (sv2.rfind( "abcde", 1) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size_size.pass.cpp
index 18fd8437d7e..c3ca97e7ff9 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/rfind_pointer_size_size.pass.cpp
@@ -365,7 +365,7 @@ void test3()
     test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 20, 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -389,4 +389,6 @@ int main()
     static_assert (sv2.rfind( "abcde", 0, 1 ) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.find/rfind_string_view_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.find/rfind_string_view_size.pass.cpp
index dfc4a836149..c4ceef33136 100644
--- a/libcxx/test/std/strings/string.view/string.view.find/rfind_string_view_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.find/rfind_string_view_size.pass.cpp
@@ -140,7 +140,7 @@ void test1()
     test(S("abcdeabcdeabcdeabcde"), S("abcdeabcdeabcdeabcde"), 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view S;
@@ -161,4 +161,6 @@ int main()
     static_assert (sv2.rfind(sv2, 1) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.hash/enabled_hashes.pass.cpp b/libcxx/test/std/strings/string.view/string.view.hash/enabled_hashes.pass.cpp
index 21dcbdf3039..d52f16303b6 100644
--- a/libcxx/test/std/strings/string.view/string.view.hash/enabled_hashes.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.hash/enabled_hashes.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::string_view>();
@@ -30,4 +30,6 @@ int main() {
     test_hash_enabled_for_type<std::u32string_view>();
 #endif
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.hash/string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.hash/string_view.pass.cpp
index 7cb7754038c..0e296f2096d 100644
--- a/libcxx/test/std/strings/string.view/string.view.hash/string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.hash/string_view.pass.cpp
@@ -55,7 +55,7 @@ test()
     assert(sh(ss2) == h(s2));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::string_view>();
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -66,4 +66,6 @@ int main()
     test<std::u32string_view>();
 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
     test<std::wstring_view>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.io/stream_insert.pass.cpp b/libcxx/test/std/strings/string.view/string.view.io/stream_insert.pass.cpp
index c721b2fcfe3..d4dcbdc6b0a 100644
--- a/libcxx/test/std/strings/string.view/string.view.io/stream_insert.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.io/stream_insert.pass.cpp
@@ -20,7 +20,7 @@
 using std::string_view;
 using std::wstring_view;
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream out;
@@ -54,4 +54,6 @@ int main()
         assert(out.good());
         assert(L"   " + s == out.str());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.iterators/begin.pass.cpp b/libcxx/test/std/strings/string.view/string.view.iterators/begin.pass.cpp
index 0926f7f9022..ba700c8abbc 100644
--- a/libcxx/test/std/strings/string.view/string.view.iterators/begin.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.iterators/begin.pass.cpp
@@ -39,7 +39,7 @@ test(S s)
 }
 
 
-int main()
+int main(int, char**)
 {
     typedef std::string_view    string_view;
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -90,4 +90,6 @@ int main()
     static_assert (   *wsv.cbegin() ==   wsv[0], "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.iterators/end.pass.cpp b/libcxx/test/std/strings/string.view/string.view.iterators/end.pass.cpp
index 1287cc201ba..59c29e2dbdd 100644
--- a/libcxx/test/std/strings/string.view/string.view.iterators/end.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.iterators/end.pass.cpp
@@ -48,7 +48,7 @@ test(S s)
 }
 
 
-int main()
+int main(int, char**)
 {
     typedef std::string_view    string_view;
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -99,4 +99,6 @@ int main()
     static_assert (   wsv.begin() !=   wsv.cend(), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.iterators/rbegin.pass.cpp b/libcxx/test/std/strings/string.view/string.view.iterators/rbegin.pass.cpp
index 43d1906c8f5..a57d7b454a3 100644
--- a/libcxx/test/std/strings/string.view/string.view.iterators/rbegin.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.iterators/rbegin.pass.cpp
@@ -40,7 +40,7 @@ test(S s)
 }
 
 
-int main()
+int main(int, char**)
 {
     typedef std::string_view    string_view;
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -91,4 +91,6 @@ int main()
     static_assert (   *wsv.crbegin() ==   wsv[2], "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.iterators/rend.pass.cpp b/libcxx/test/std/strings/string.view/string.view.iterators/rend.pass.cpp
index a4eed7d9743..e0db02c22f6 100644
--- a/libcxx/test/std/strings/string.view/string.view.iterators/rend.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.iterators/rend.pass.cpp
@@ -48,7 +48,7 @@ test(S s)
 }
 
 
-int main()
+int main(int, char**)
 {
     typedef std::string_view    string_view;
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
@@ -99,4 +99,6 @@ int main()
     static_assert (   *--wsv.crend() ==   wsv[0], "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.modifiers/remove_prefix.pass.cpp b/libcxx/test/std/strings/string.view/string.view.modifiers/remove_prefix.pass.cpp
index 08fe79e8f82..2287ba6c800 100644
--- a/libcxx/test/std/strings/string.view/string.view.modifiers/remove_prefix.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.modifiers/remove_prefix.pass.cpp
@@ -47,7 +47,7 @@ constexpr size_t test_ce ( size_t n, size_t k ) {
 }
 #endif
 
-int main () {
+int main(int, char**) {
     test ( "ABCDE", 5 );
     test ( "a", 1 );
     test ( "", 0 );
@@ -74,4 +74,6 @@ int main () {
     static_assert ( test_ce ( 9, 3 ) == 6, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.modifiers/remove_suffix.pass.cpp b/libcxx/test/std/strings/string.view/string.view.modifiers/remove_suffix.pass.cpp
index be9ca1e1fc9..0636bcea957 100644
--- a/libcxx/test/std/strings/string.view/string.view.modifiers/remove_suffix.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.modifiers/remove_suffix.pass.cpp
@@ -47,7 +47,7 @@ constexpr size_t test_ce ( size_t n, size_t k ) {
 }
 #endif
 
-int main () {
+int main(int, char**) {
     test ( "ABCDE", 5 );
     test ( "a", 1 );
     test ( "", 0 );
@@ -74,4 +74,6 @@ int main () {
     static_assert ( test_ce ( 9, 3 ) == 6, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.modifiers/swap.pass.cpp b/libcxx/test/std/strings/string.view/string.view.modifiers/swap.pass.cpp
index 9b8eedd701b..2fc286e96a5 100644
--- a/libcxx/test/std/strings/string.view/string.view.modifiers/swap.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.modifiers/swap.pass.cpp
@@ -46,7 +46,7 @@ constexpr size_t test_ce ( size_t n, size_t k ) {
 #endif
 
 
-int main () {
+int main(int, char**) {
     test ( "ABCDE", 5 );
     test ( "a", 1 );
     test ( "", 0 );
@@ -72,4 +72,6 @@ int main () {
     static_assert ( test_ce (0, 1) == 1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.nonmem/quoted.pass.cpp b/libcxx/test/std/strings/string.view/string.view.nonmem/quoted.pass.cpp
index f335da9585d..ecc24abf4be 100644
--- a/libcxx/test/std/strings/string.view/string.view.nonmem/quoted.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.nonmem/quoted.pass.cpp
@@ -160,7 +160,7 @@ std::wstring unquote ( const wchar_t *p, wchar_t delim='"', wchar_t escape='\\'
     return s;
 }
 
-int main()
+int main(int, char**)
 {
     round_trip    (  "" );
     round_trip_ws (  "" );
@@ -207,7 +207,11 @@ int main()
 
     assert ( unquote (  "" ) ==  "" ); // nothing there
     assert ( unquote ( L"" ) == L"" ); // nothing there
-    }
+
+    return 0;
+}
 #else
-int main() {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer.pass.cpp
index e9a854b34fa..0c04ce5e48b 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer.pass.cpp
@@ -32,7 +32,7 @@ test( const CharT *s1, const CharT *s2, int expected)
     test1 ( sv1, s2, expected );
 }
 
-int main()
+int main(int, char**)
 {
     {
     test("", "", 0);
@@ -123,4 +123,6 @@ int main()
     static_assert ( sv2.compare("abcde") == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer_size.pass.cpp
index 6f45222ff6c..974e687100d 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/compare.pointer_size.pass.cpp
@@ -354,7 +354,7 @@ void test2()
 }
 
 
-int main()
+int main(int, char**)
 {
     test0();
     test1();
@@ -449,4 +449,6 @@ int main()
     static_assert ( sv2.compare(0, 6, "abcde") == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv.pass.cpp
index 452addc12df..73773fb26ee 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv.pass.cpp
@@ -354,7 +354,7 @@ void test2()
 }
 
 
-int main () {
+int main(int, char**) {
     test0();
     test1();
     test2();
@@ -398,4 +398,6 @@ int main () {
     static_assert ( sv1.compare(2, 4, sv2) == 1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_pointer_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_pointer_size.pass.cpp
index d11f003313f..df4e7394db9 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_pointer_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_pointer_size.pass.cpp
@@ -1291,7 +1291,7 @@ void test11()
     }
 
 
-int main () {
+int main(int, char**) {
     test0();
     test1();
     test2();
@@ -1349,4 +1349,6 @@ int main () {
     static_assert ( sv2.compare(0, 0, "abcde", 1, 0) == 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_size_size.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_size_size.pass.cpp
index 3f6e5787603..56b6ec1f404 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_size_size.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/compare.size_size_sv_size_size.pass.cpp
@@ -5747,7 +5747,7 @@ void test54()
 }
 
 
-int main () {
+int main(int, char**) {
     test0();
     test1();
     test2();
@@ -5844,4 +5844,6 @@ int main () {
     static_assert ( sv1.compare(2, 4, "abcde", 3, 4) == -1, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/compare.sv.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/compare.sv.pass.cpp
index e65a7451f47..9c27f267459 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/compare.sv.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/compare.sv.pass.cpp
@@ -34,7 +34,7 @@ void test ( const CharT *s1, const CharT  *s2, int expected ) {
     test1(sv1, sv2, expected);
 }
 
-int main () {
+int main(int, char**) {
 
     test("",                     "", 0);
     test("",                     "abcde", -5);
@@ -118,4 +118,6 @@ int main () {
     static_assert ( sv2.compare(sv3)  < 0, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/copy.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/copy.pass.cpp
index 3ec48b08c33..e96650992cb 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/copy.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/copy.pass.cpp
@@ -77,7 +77,7 @@ void test ( const CharT *s ) {
 
 }
 
-int main () {
+int main(int, char**) {
     test ( "ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
     test ( "ABCDE");
     test ( "a" );
@@ -99,4 +99,6 @@ int main () {
     test ( U"a" );
     test ( U"" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.ops/substr.pass.cpp b/libcxx/test/std/strings/string.view/string.view.ops/substr.pass.cpp
index 4391bb51342..c2fd01f5724 100644
--- a/libcxx/test/std/strings/string.view/string.view.ops/substr.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.ops/substr.pass.cpp
@@ -69,7 +69,7 @@ void test ( const CharT *s ) {
     test1(sv1, sv1.size() + 1, string_view_t::npos);
 }
 
-int main () {
+int main(int, char**) {
     test ( "ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
     test ( "ABCDE");
     test ( "a" );
@@ -117,4 +117,6 @@ int main () {
     }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.synop/nothing_to_do.pass.cpp b/libcxx/test/std/strings/string.view/string.view.synop/nothing_to_do.pass.cpp
index 3f07051d03a..45edec7f4b0 100644
--- a/libcxx/test/std/strings/string.view/string.view.synop/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.synop/nothing_to_do.pass.cpp
@@ -8,4 +8,6 @@
 
 #include <string_view>
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/strings/string.view/string.view.template/ends_with.char.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/ends_with.char.pass.cpp
index c89fdb8e4e8..c0373307427 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/ends_with.char.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/ends_with.char.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "constexpr_char_traits.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view SV;
@@ -43,4 +43,6 @@ int main()
     static_assert (!sv2.ends_with('x'), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.template/ends_with.ptr.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/ends_with.ptr.pass.cpp
index 4ef1c8e2f98..64caf5cc0d5 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/ends_with.ptr.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/ends_with.ptr.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "constexpr_char_traits.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view SV;
@@ -100,4 +100,6 @@ int main()
     static_assert ( svNot.ends_with("def"), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.template/ends_with.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/ends_with.string_view.pass.cpp
index 2d115c104b4..b5f67f8ddd1 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/ends_with.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/ends_with.string_view.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "constexpr_char_traits.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view SV;
@@ -100,4 +100,6 @@ int main()
     static_assert ( svNot.ends_with(svNot), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.template/nothing_to_do.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/nothing_to_do.pass.cpp
index 3f07051d03a..45edec7f4b0 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/nothing_to_do.pass.cpp
@@ -8,4 +8,6 @@
 
 #include <string_view>
 
-int main () {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/strings/string.view/string.view.template/starts_with.char.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/starts_with.char.pass.cpp
index d35222bbf87..d43944fdec7 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/starts_with.char.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/starts_with.char.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "constexpr_char_traits.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view SV;
@@ -43,4 +43,6 @@ int main()
     static_assert (!sv2.starts_with('x'), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp
index a3ffde5c584..ce651ec57e0 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/starts_with.ptr.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "constexpr_char_traits.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view SV;
@@ -100,4 +100,6 @@ int main()
     static_assert ( svNot.starts_with("def"), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string.view.template/starts_with.string_view.pass.cpp b/libcxx/test/std/strings/string.view/string.view.template/starts_with.string_view.pass.cpp
index 5a5adbd8470..3d184bae0eb 100644
--- a/libcxx/test/std/strings/string.view/string.view.template/starts_with.string_view.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.template/starts_with.string_view.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "constexpr_char_traits.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::string_view SV;
@@ -100,4 +100,6 @@ int main()
     static_assert ( svNot.starts_with(svNot), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string_view.literals/literal.pass.cpp b/libcxx/test/std/strings/string.view/string_view.literals/literal.pass.cpp
index c7d0e054df1..a8a1dff6404 100644
--- a/libcxx/test/std/strings/string.view/string_view.literals/literal.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string_view.literals/literal.pass.cpp
@@ -23,7 +23,7 @@
     typedef std::string_view   u8string_view;
 #endif
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::string_view_literals;
 
@@ -69,4 +69,6 @@ int main()
     static_assert(noexcept( L"ABC"sv), "");
     static_assert(noexcept( u"ABC"sv), "");
     static_assert(noexcept( U"ABC"sv), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string_view.literals/literal1.fail.cpp b/libcxx/test/std/strings/string.view/string_view.literals/literal1.fail.cpp
index 05e66bf1eaf..5bf108bbef2 100644
--- a/libcxx/test/std/strings/string.view/string_view.literals/literal1.fail.cpp
+++ b/libcxx/test/std/strings/string.view/string_view.literals/literal1.fail.cpp
@@ -14,9 +14,11 @@
 #include <string_view>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using std::string_view;
 
     string_view foo  =   ""sv;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string_view.literals/literal1.pass.cpp b/libcxx/test/std/strings/string.view/string_view.literals/literal1.pass.cpp
index 956d7d26a32..ba667e09cd1 100644
--- a/libcxx/test/std/strings/string.view/string_view.literals/literal1.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string_view.literals/literal1.pass.cpp
@@ -15,10 +15,12 @@
 #include <string_view>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals;
 
     std::string_view foo  =   ""sv;
     assert(foo.length() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string_view.literals/literal2.fail.cpp b/libcxx/test/std/strings/string.view/string_view.literals/literal2.fail.cpp
index 672201bb9a0..2287e1ce92a 100644
--- a/libcxx/test/std/strings/string.view/string_view.literals/literal2.fail.cpp
+++ b/libcxx/test/std/strings/string.view/string_view.literals/literal2.fail.cpp
@@ -14,7 +14,9 @@
 #include <string_view>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::string_view foo  =   ""sv;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string_view.literals/literal2.pass.cpp b/libcxx/test/std/strings/string.view/string_view.literals/literal2.pass.cpp
index 653738dc5a3..cb49280bfec 100644
--- a/libcxx/test/std/strings/string.view/string_view.literals/literal2.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string_view.literals/literal2.pass.cpp
@@ -15,10 +15,12 @@
 #include <string_view>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::string_view_literals;
 
     std::string_view foo  =   ""sv;
     assert(foo.length() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/string_view.literals/literal3.pass.cpp b/libcxx/test/std/strings/string.view/string_view.literals/literal3.pass.cpp
index 814ec0cbdfe..710933dd95a 100644
--- a/libcxx/test/std/strings/string.view/string_view.literals/literal3.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string_view.literals/literal3.pass.cpp
@@ -15,10 +15,12 @@
 #include <string_view>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std;
 
     string_view foo  =   ""sv;
     assert(foo.length() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/traits_mismatch.fail.cpp b/libcxx/test/std/strings/string.view/traits_mismatch.fail.cpp
index 6a32051a1c3..5cf3fa94793 100644
--- a/libcxx/test/std/strings/string.view/traits_mismatch.fail.cpp
+++ b/libcxx/test/std/strings/string.view/traits_mismatch.fail.cpp
@@ -11,7 +11,9 @@
 
 #include <string_view>
 
-int main()
+int main(int, char**)
 {
     std::basic_string_view<char, std::char_traits<wchar_t>> s;
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/string.view/types.pass.cpp b/libcxx/test/std/strings/string.view/types.pass.cpp
index d8bb0f73737..d90f777babf 100644
--- a/libcxx/test/std/strings/string.view/types.pass.cpp
+++ b/libcxx/test/std/strings/string.view/types.pass.cpp
@@ -67,7 +67,7 @@ test()
     static_assert((std::is_same<typename S::reverse_iterator, typename S::const_reverse_iterator>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::char_traits<char> >();
     test<std::char_traits<wchar_t> >();
@@ -76,4 +76,6 @@ int main()
 #endif
     static_assert((std::is_same<std::basic_string_view<char>::traits_type,
                                 std::char_traits<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/strings.erasure/erase.pass.cpp b/libcxx/test/std/strings/strings.erasure/erase.pass.cpp
index 250fe94a6f2..5013300d28b 100644
--- a/libcxx/test/std/strings/strings.erasure/erase.pass.cpp
+++ b/libcxx/test/std/strings/strings.erasure/erase.pass.cpp
@@ -67,9 +67,11 @@ void test()
     test0(S("aba"), opt('c'), S("aba"));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::string>();
     test<std::basic_string<char, std::char_traits<char>, min_allocator<char>>> ();
     test<std::basic_string<char, std::char_traits<char>, test_allocator<char>>> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/strings.erasure/erase_if.pass.cpp b/libcxx/test/std/strings/strings.erasure/erase_if.pass.cpp
index 06b9cc2279a..5f2fb0117f8 100644
--- a/libcxx/test/std/strings/strings.erasure/erase_if.pass.cpp
+++ b/libcxx/test/std/strings/strings.erasure/erase_if.pass.cpp
@@ -67,9 +67,11 @@ void test()
     test0(S("aba"), True,   S(""));
 }
 
-int main()
+int main(int, char**)
 {
     test<std::string>();
     test<std::basic_string<char, std::char_traits<char>, min_allocator<char>>> ();
     test<std::basic_string<char, std::char_traits<char>, test_allocator<char>>> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/strings/strings.general/nothing_to_do.pass.cpp b/libcxx/test/std/strings/strings.general/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/strings/strings.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/strings/strings.general/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.async/async.fail.cpp b/libcxx/test/std/thread/futures/futures.async/async.fail.cpp
index f93c3ef20ff..3e7fb80e0e1 100644
--- a/libcxx/test/std/thread/futures/futures.async/async.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.async/async.fail.cpp
@@ -30,8 +30,10 @@
 
 int foo (int x) { return x; }
 
-int main ()
+int main(int, char**)
 {
     std::async(                    foo, 3); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
     std::async(std::launch::async, foo, 3); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.async/async.pass.cpp b/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
index 1083cb47d44..225b63ec889 100644
--- a/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
@@ -102,7 +102,7 @@ void test(CheckLamdba&& getAndCheckFn, bool IsDeferred, Args&&... args) {
     }
 }
 
-int main()
+int main(int, char**)
 {
     // The default launch policy is implementation defined. libc++ defines
     // it to be std::launch::async.
@@ -151,4 +151,5 @@ int main()
         try { f.get(); assert (false); } catch ( int ) {}
     }
 #endif
+    return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.async/async_race.38682.pass.cpp b/libcxx/test/std/thread/futures/futures.async/async_race.38682.pass.cpp
index 6e115f00404..826704a75d3 100644
--- a/libcxx/test/std/thread/futures/futures.async/async_race.38682.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.async/async_race.38682.pass.cpp
@@ -38,7 +38,7 @@ static int& worker_ref(int& i) { return i; }
 
 static void worker_void() { }
 
-int main() {
+int main(int, char**) {
   // future<T>
   {
     std::vector<int> const v{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
@@ -65,4 +65,6 @@ int main() {
       fut.get();
     }
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.async/async_race.pass.cpp b/libcxx/test/std/thread/futures/futures.async/async_race.pass.cpp
index 62e09723e9e..9da57e38ae9 100644
--- a/libcxx/test/std/thread/futures/futures.async/async_race.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.async/async_race.pass.cpp
@@ -62,6 +62,8 @@ void test_each() {
     }
 }
 
-int main() {
+int main(int, char**) {
     for (int i=0; i < 25; ++i) test_each();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.errors/default_error_condition.pass.cpp b/libcxx/test/std/thread/futures/futures.errors/default_error_condition.pass.cpp
index 1676d4babae..fbb7eb13d92 100644
--- a/libcxx/test/std/thread/futures/futures.errors/default_error_condition.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.errors/default_error_condition.pass.cpp
@@ -17,10 +17,12 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat = std::future_category();
     std::error_condition e_cond = e_cat.default_error_condition(static_cast<int>(std::errc::not_a_directory));
     assert(e_cond.category() == e_cat);
     assert(e_cond.value() == static_cast<int>(std::errc::not_a_directory));
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.errors/equivalent_error_code_int.pass.cpp b/libcxx/test/std/thread/futures/futures.errors/equivalent_error_code_int.pass.cpp
index cb3f8139367..3ba3410942d 100644
--- a/libcxx/test/std/thread/futures/futures.errors/equivalent_error_code_int.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.errors/equivalent_error_code_int.pass.cpp
@@ -17,9 +17,11 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat = std::future_category();
     assert(e_cat.equivalent(std::error_code(5, e_cat), 5));
     assert(!e_cat.equivalent(std::error_code(5, e_cat), 6));
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.errors/equivalent_int_error_condition.pass.cpp b/libcxx/test/std/thread/futures/futures.errors/equivalent_int_error_condition.pass.cpp
index f39de5b11f7..9d0e1cf31ba 100644
--- a/libcxx/test/std/thread/futures/futures.errors/equivalent_int_error_condition.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.errors/equivalent_int_error_condition.pass.cpp
@@ -17,10 +17,12 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& e_cat = std::future_category();
     std::error_condition e_cond = e_cat.default_error_condition(5);
     assert(e_cat.equivalent(5, e_cond));
     assert(!e_cat.equivalent(6, e_cond));
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.errors/future_category.pass.cpp b/libcxx/test/std/thread/futures/futures.errors/future_category.pass.cpp
index e9e784c28d1..7b9d7234425 100644
--- a/libcxx/test/std/thread/futures/futures.errors/future_category.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.errors/future_category.pass.cpp
@@ -16,8 +16,10 @@
 #include <cstring>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::error_category& ec = std::future_category();
     assert(std::strcmp(ec.name(), "future") == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.errors/make_error_code.pass.cpp b/libcxx/test/std/thread/futures/futures.errors/make_error_code.pass.cpp
index 9e39585c846..d9e50bf42d3 100644
--- a/libcxx/test/std/thread/futures/futures.errors/make_error_code.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.errors/make_error_code.pass.cpp
@@ -17,11 +17,13 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec = make_error_code(std::future_errc::broken_promise);
         assert(ec.value() == static_cast<int>(std::future_errc::broken_promise));
         assert(ec.category() == std::future_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.errors/make_error_condition.pass.cpp b/libcxx/test/std/thread/futures/futures.errors/make_error_condition.pass.cpp
index f8cbbdedbde..d0555910246 100644
--- a/libcxx/test/std/thread/futures/futures.errors/make_error_condition.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.errors/make_error_condition.pass.cpp
@@ -17,7 +17,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         const std::error_condition ec1 =
@@ -26,4 +26,6 @@ int main()
                   static_cast<int>(std::future_errc::future_already_retrieved));
         assert(ec1.category() == std::future_category());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp b/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp
index 63769f018b7..53acba393fb 100644
--- a/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::error_code ec = std::make_error_code(std::future_errc::broken_promise);
@@ -53,4 +53,6 @@ int main()
         assert(f.code() == std::make_error_code(std::future_errc::no_state));
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.future_error/types.pass.cpp b/libcxx/test/std/thread/futures/futures.future_error/types.pass.cpp
index 911f562e510..edf18ba5a9a 100644
--- a/libcxx/test/std/thread/futures/futures.future_error/types.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.future_error/types.pass.cpp
@@ -15,8 +15,10 @@
 #include <future>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_convertible<std::future_error*,
                                        std::logic_error*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp b/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp
index bae25af1fab..468aeb85bec 100644
--- a/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::future_error f(std::make_error_code(std::future_errc::broken_promise));
@@ -50,4 +50,6 @@ int main()
         LIBCPP_ASSERT(std::strcmp(f.what(), "Operation not permitted on an object without "
                       "an associated state.") == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.overview/future_errc.pass.cpp b/libcxx/test/std/thread/futures/futures.overview/future_errc.pass.cpp
index 383407d1328..d7840f45ce6 100644
--- a/libcxx/test/std/thread/futures/futures.overview/future_errc.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.overview/future_errc.pass.cpp
@@ -23,7 +23,7 @@
 
 #include <future>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::future_errc::broken_promise != std::future_errc::future_already_retrieved, "");
     static_assert(std::future_errc::broken_promise != std::future_errc::promise_already_satisfied, "");
@@ -36,4 +36,6 @@ int main()
     static_assert(std::future_errc::future_already_retrieved != static_cast<std::future_errc>(0), "");
     static_assert(std::future_errc::promise_already_satisfied != static_cast<std::future_errc>(0), "");
     static_assert(std::future_errc::no_state != static_cast<std::future_errc>(0), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.overview/future_status.pass.cpp b/libcxx/test/std/thread/futures/futures.overview/future_status.pass.cpp
index 23c5bac06b7..ceff64f7ebb 100644
--- a/libcxx/test/std/thread/futures/futures.overview/future_status.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.overview/future_status.pass.cpp
@@ -19,9 +19,11 @@
 
 #include <future>
 
-int main()
+int main(int, char**)
 {
     static_assert(static_cast<int>(std::future_status::ready) == 0, "");
     static_assert(static_cast<int>(std::future_status::timeout) == 1, "");
     static_assert(static_cast<int>(std::future_status::deferred) == 2, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.overview/is_error_code_enum_future_errc.pass.cpp b/libcxx/test/std/thread/futures/futures.overview/is_error_code_enum_future_errc.pass.cpp
index f8a0d8a6492..c7e2c2aebaa 100644
--- a/libcxx/test/std/thread/futures/futures.overview/is_error_code_enum_future_errc.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.overview/is_error_code_enum_future_errc.pass.cpp
@@ -15,10 +15,12 @@
 #include <future>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_error_code_enum  <std::future_errc>::value, "");
 #if TEST_STD_VER > 14
     static_assert(std::is_error_code_enum_v<std::future_errc>, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.overview/launch.pass.cpp b/libcxx/test/std/thread/futures/futures.overview/launch.pass.cpp
index 0ed166028c4..6d405b508ed 100644
--- a/libcxx/test/std/thread/futures/futures.overview/launch.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.overview/launch.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
    LIBCPP_STATIC_ASSERT(static_cast<int>(std::launch::any) ==
@@ -43,4 +43,6 @@ int main()
 #endif
     static_assert(static_cast<int>(std::launch::async) == 1, "");
     static_assert(static_cast<int>(std::launch::deferred) == 2, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/alloc_ctor.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/alloc_ctor.pass.cpp
index 1ad295220af..ece8b94a563 100644
--- a/libcxx/test/std/thread/futures/futures.promise/alloc_ctor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/alloc_ctor.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_allocator.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     assert(test_alloc_base::alloc_count == 0);
     {
@@ -81,4 +81,6 @@ int main()
         std::future<void> f = p.get_future();
         assert(f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/copy_assign.fail.cpp b/libcxx/test/std/thread/futures/futures.promise/copy_assign.fail.cpp
index 895ccf7fd5b..bf46a6847cb 100644
--- a/libcxx/test/std/thread/futures/futures.promise/copy_assign.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/copy_assign.fail.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -47,4 +47,6 @@ int main()
         p = p0; // expected-error {{'operator=' is a private member of 'std::__1::promise<void>'}}
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/copy_ctor.fail.cpp b/libcxx/test/std/thread/futures/futures.promise/copy_ctor.fail.cpp
index 00af4af49ce..8f90f3da7fe 100644
--- a/libcxx/test/std/thread/futures/futures.promise/copy_ctor.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/copy_ctor.fail.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -47,4 +47,6 @@ int main()
         std::promise<void> p(p0); // expected-error {{calling a private constructor of class 'std::__1::promise<void>'}}
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/default.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/default.pass.cpp
index f0e3a786d6c..600f99dd992 100644
--- a/libcxx/test/std/thread/futures/futures.promise/default.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/default.pass.cpp
@@ -18,7 +18,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::promise<int> p;
@@ -35,4 +35,6 @@ int main()
         std::future<void> f = p.get_future();
         assert(f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/dtor.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/dtor.pass.cpp
index 4d3bd9cb988..49c4b4685db 100644
--- a/libcxx/test/std/thread/futures/futures.promise/dtor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/dtor.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -123,4 +123,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/get_future.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/get_future.pass.cpp
index 3805a96d04a..6385f6345de 100644
--- a/libcxx/test/std/thread/futures/futures.promise/get_future.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/get_future.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::promise<double> p;
@@ -56,4 +56,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/move_assign.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/move_assign.pass.cpp
index 46860fbe840..6592e0bb881 100644
--- a/libcxx/test/std/thread/futures/futures.promise/move_assign.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/move_assign.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     assert(test_alloc_base::alloc_count == 0);
     {
@@ -93,4 +93,6 @@ int main()
         assert(test_alloc_base::alloc_count == 1);
     }
     assert(test_alloc_base::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/move_ctor.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/move_ctor.pass.cpp
index d119b188df1..1551420e978 100644
--- a/libcxx/test/std/thread/futures/futures.promise/move_ctor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/move_ctor.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     assert(test_alloc_base::alloc_count == 0);
     {
@@ -87,4 +87,6 @@ int main()
 #endif
     }
     assert(test_alloc_base::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_exception.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_exception.pass.cpp
index bb763e9ac51..030620ad43f 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_exception.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_exception.pass.cpp
@@ -19,7 +19,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -45,4 +45,6 @@ int main()
             assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
index c464d083bb5..a1a32882bee 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
@@ -24,7 +24,7 @@ void func(std::promise<int> p)
     p.set_exception_at_thread_exit(std::make_exception_ptr(3));
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -41,4 +41,6 @@ int main()
             assert(i == 3);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_lvalue.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_lvalue.pass.cpp
index 9b72e480371..db8bb5704c5 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_lvalue.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_lvalue.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int& T;
@@ -44,4 +44,6 @@ int main()
         }
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_lvalue_at_thread_exit.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_lvalue_at_thread_exit.pass.cpp
index 0fa28031dd0..9c3b09086b3 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_lvalue_at_thread_exit.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_lvalue_at_thread_exit.pass.cpp
@@ -27,7 +27,7 @@ void func(std::promise<int&> p)
     i = 4;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::promise<int&> p;
@@ -35,4 +35,6 @@ int main()
         std::thread(func, std::move(p)).detach();
         assert(f.get() == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_rvalue.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_rvalue.pass.cpp
index d0f2bda4378..7f54baa8cec 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_rvalue.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_rvalue.pass.cpp
@@ -26,7 +26,7 @@ struct A
     A(A&&) {throw 9;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::unique_ptr<int> T;
@@ -60,4 +60,6 @@ int main()
             assert(j == 9);
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_rvalue_at_thread_exit.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_rvalue_at_thread_exit.pass.cpp
index a5574238da5..bddd6613556 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_rvalue_at_thread_exit.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_rvalue_at_thread_exit.pass.cpp
@@ -23,7 +23,7 @@ void func(std::promise<std::unique_ptr<int>> p)
     p.set_value_at_thread_exit(std::unique_ptr<int>(new int(5)));
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::promise<std::unique_ptr<int>> p;
@@ -31,4 +31,6 @@ int main()
         std::thread(func, std::move(p)).detach();
         assert(*f.get() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_const.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_const.pass.cpp
index 4760611771a..9258a001149 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_const.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_const.pass.cpp
@@ -24,7 +24,7 @@ void func(std::promise<int> p)
     p.set_value_at_thread_exit(i);
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::promise<int> p;
@@ -32,4 +32,6 @@ int main()
         std::thread(func, std::move(p)).detach();
         assert(f.get() == 5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_void.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_void.pass.cpp
index e2b8ae9a5da..1a204421ee9 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_void.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_value_at_thread_exit_void.pass.cpp
@@ -27,7 +27,7 @@ void func(std::promise<void> p)
     i = 1;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::promise<void> p;
@@ -36,4 +36,6 @@ int main()
         f.get();
         assert(i == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_value_const.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_value_const.pass.cpp
index 942481542f9..e58d2d24588 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_value_const.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_value_const.pass.cpp
@@ -28,7 +28,7 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -68,4 +68,6 @@ int main()
         }
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/set_value_void.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/set_value_void.pass.cpp
index 330d5b02508..d505b3aabf4 100644
--- a/libcxx/test/std/thread/futures/futures.promise/set_value_void.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/set_value_void.pass.cpp
@@ -19,7 +19,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef void T;
@@ -37,4 +37,6 @@ int main()
             assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
         }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/swap.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/swap.pass.cpp
index ec72f8794b0..2b78b1d384b 100644
--- a/libcxx/test/std/thread/futures/futures.promise/swap.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/swap.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     assert(test_alloc_base::alloc_count == 0);
     {
@@ -81,4 +81,6 @@ int main()
         assert(test_alloc_base::alloc_count == 1);
     }
     assert(test_alloc_base::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.promise/uses_allocator.pass.cpp b/libcxx/test/std/thread/futures/futures.promise/uses_allocator.pass.cpp
index 928ede9fb83..1a5028bce3a 100644
--- a/libcxx/test/std/thread/futures/futures.promise/uses_allocator.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.promise/uses_allocator.pass.cpp
@@ -19,9 +19,11 @@
 #include <future>
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::uses_allocator<std::promise<int>, test_allocator<int> >::value), "");
     static_assert((std::uses_allocator<std::promise<int&>, test_allocator<int> >::value), "");
     static_assert((std::uses_allocator<std::promise<void>, test_allocator<void> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/copy_assign.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/copy_assign.pass.cpp
index 44c538c972e..e5cc33a0c94 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/copy_assign.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/copy_assign.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -77,4 +77,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/copy_ctor.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/copy_ctor.pass.cpp
index 2878c40d10b..01b5572e3f3 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/copy_ctor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/copy_ctor.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -71,4 +71,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/ctor_future.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/ctor_future.pass.cpp
index 10b84a4118a..b75450cb9e9 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/ctor_future.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/ctor_future.pass.cpp
@@ -18,7 +18,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -65,4 +65,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/default.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/default.pass.cpp
index 2229ee58e3d..0387b97a70c 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/default.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/default.pass.cpp
@@ -17,7 +17,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_future<int> f;
@@ -31,4 +31,6 @@ int main()
         std::shared_future<void> f;
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/dtor.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/dtor.pass.cpp
index 964180b9898..fe49c2208ee 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/dtor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/dtor.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     assert(test_alloc_base::alloc_count == 0);
     {
@@ -66,4 +66,6 @@ int main()
         assert(f.valid());
     }
     assert(test_alloc_base::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/get.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/get.pass.cpp
index b7767b379ac..038ca71510f 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/get.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/get.pass.cpp
@@ -61,7 +61,7 @@ void func6(std::promise<void> p)
     p.set_exception(std::make_exception_ptr('c'));
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -150,4 +150,6 @@ int main()
         }
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/move_assign.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/move_assign.pass.cpp
index b68ee6921de..3940530528d 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/move_assign.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/move_assign.pass.cpp
@@ -18,7 +18,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -71,4 +71,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/move_ctor.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/move_ctor.pass.cpp
index c2b52dc1b18..e1d982d0ee1 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/move_ctor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/move_ctor.pass.cpp
@@ -18,7 +18,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -65,4 +65,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp
index 11dc4ba3d13..f78ca6bfc42 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp
@@ -39,7 +39,7 @@ void func5(std::promise<void> p)
     p.set_value();
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock Clock;
     typedef std::chrono::duration<double, std::milli> ms;
@@ -85,4 +85,6 @@ int main()
         assert(f.valid());
         assert(t1-t0 < ms(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp
index 4fbd8ae7977..913127af327 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp
@@ -43,7 +43,7 @@ void func5(std::promise<void> p)
     p.set_value();
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock Clock;
     {
@@ -94,4 +94,6 @@ int main()
         assert(f.valid());
         assert(t1-t0 < ms(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
index 02b0ce716e0..09787fedc3a 100644
--- a/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
@@ -62,7 +62,7 @@ void func5(std::promise<void> p)
     set_worker_thread_state(WorkerThreadState::Exiting);
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock Clock;
     {
@@ -128,4 +128,6 @@ int main()
         assert(f.valid());
         assert(t1-t0 < ms(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.state/nothing_to_do.pass.cpp b/libcxx/test/std/thread/futures/futures.state/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/thread/futures/futures.state/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.state/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_copy.fail.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_copy.fail.cpp
index b14f2381a8d..a8b8581893d 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_copy.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_copy.fail.cpp
@@ -17,10 +17,12 @@
 
 #include <future>
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p0, p;
         p = p0; // expected-error {{overload resolution selected deleted operator '='}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_move.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_move.pass.cpp
index 655a9d7f8da..9da7a96e241 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_move.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/assign_move.pass.cpp
@@ -28,7 +28,7 @@ public:
     long operator()(long i, long j) const {return data_ + i + j;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p0(A(5));
@@ -47,4 +47,6 @@ int main()
         assert(!p0.valid());
         assert(!p.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor1.fail.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor1.fail.cpp
index fbe3b55a81d..ec081dc328e 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor1.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor1.fail.cpp
@@ -25,11 +25,13 @@ typedef std::packaged_task<A(int, char)> PT;
 typedef volatile std::packaged_task<A(int, char)> VPT;
 
 
-int main()
+int main(int, char**)
 {
     VPT init{};
     auto const& c_init = init;
     PT p1{init}; // expected-error {{no matching constructor}}
     PT p2{c_init}; // expected-error {{no matching constructor}}
     PT p3{std::move(init)}; // expected-error {{no matching constructor for initialization of 'PT' (aka 'packaged_task<A (int, char)>')}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor2.fail.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor2.fail.cpp
index cae4e1afd45..76273a3eaa7 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor2.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor2.fail.cpp
@@ -26,8 +26,10 @@ struct A {};
 typedef std::packaged_task<A(int, char)> PT;
 typedef volatile std::packaged_task<A(int, char)> VPT;
 
-int main()
+int main(int, char**)
 {
     PT p { std::allocator_arg_t{}, test_allocator<A>{}, VPT {}}; // expected-error {{no matching constructor for initialization of 'PT' (aka 'packaged_task<A (int, char)>')}}
     // expected-note-re@future:* 1 {{candidate template ignored: {{(disabled by 'enable_if')|(requirement '.*' was not satisfied)}}}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_copy.fail.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_copy.fail.cpp
index 6416df4de91..0816a1cc5b6 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_copy.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_copy.fail.cpp
@@ -18,10 +18,12 @@
 #include <future>
 
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p0;
         std::packaged_task<double(int, char)> p(p0); // expected-error {{call to deleted constructor of 'std::packaged_task<double (int, char)>'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_default.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_default.pass.cpp
index 30c45eaab51..5472c717adc 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_default.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_default.pass.cpp
@@ -20,8 +20,10 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     std::packaged_task<A(int, char)> p;
     assert(!p.valid());
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func.pass.cpp
index 3da276ba8c3..20ee8b4b4d2 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func.pass.cpp
@@ -39,7 +39,7 @@ int A::n_copies = 0;
 
 int func(int i) { return i; }
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p(A(5));
@@ -76,4 +76,6 @@ int main()
         p(4);
         assert(f.get() == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func_alloc.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func_alloc.pass.cpp
index 334ed8f9806..766987ce0df 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func_alloc.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_func_alloc.pass.cpp
@@ -44,7 +44,7 @@ int A::n_copies = 0;
 
 int func(int i) { return i; }
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p(std::allocator_arg,
@@ -123,4 +123,6 @@ int main()
     }
     A::n_copies = 0;
     A::n_moves  = 0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_move.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_move.pass.cpp
index e2e44473ef2..c517182d3ad 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_move.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/ctor_move.pass.cpp
@@ -28,7 +28,7 @@ public:
     long operator()(long i, long j) const {return data_ + i + j;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p0(A(5));
@@ -45,4 +45,6 @@ int main()
         assert(!p0.valid());
         assert(!p.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp
index e910d7c4ce8..3b794b7f6c9 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp
@@ -39,7 +39,7 @@ void func2(std::packaged_task<double(int, char)> p)
     p(3, 'a');
 }
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     {
@@ -64,4 +64,6 @@ int main()
         std::thread(func2, std::move(p)).detach();
         assert(f.get() == 105.0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/get_future.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/get_future.pass.cpp
index a4c9c7af490..8713db0a7e8 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/get_future.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/get_future.pass.cpp
@@ -30,7 +30,7 @@ public:
     long operator()(long i, long j) const {return data_ + i + j;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p(A(5));
@@ -65,4 +65,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/make_ready_at_thread_exit.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/make_ready_at_thread_exit.pass.cpp
index 21a567ca0bd..47009952298 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/make_ready_at_thread_exit.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/make_ready_at_thread_exit.pass.cpp
@@ -80,7 +80,7 @@ void func3(std::packaged_task<double(int, char)> p)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p(A(5));
@@ -115,4 +115,6 @@ int main()
         t.join();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/operator.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/operator.pass.cpp
index e148ddfc97a..536888057a9 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/operator.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/operator.pass.cpp
@@ -80,7 +80,7 @@ void func3(std::packaged_task<double(int, char)> p)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p(A(5));
@@ -116,4 +116,6 @@ int main()
         t.join();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/reset.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/reset.pass.cpp
index 7e4dd5522ca..e9f59cdfe3c 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/reset.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/reset.pass.cpp
@@ -33,7 +33,7 @@ public:
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p(A(5));
@@ -59,4 +59,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.members/swap.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.members/swap.pass.cpp
index 22e680f2aca..2cd97900df7 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.members/swap.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.members/swap.pass.cpp
@@ -28,7 +28,7 @@ public:
     long operator()(long i, long j) const {return data_ + i + j;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p0(A(5));
@@ -47,4 +47,6 @@ int main()
         assert(!p0.valid());
         assert(!p.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp
index b344398fe52..8c1c19eca62 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp
@@ -30,7 +30,7 @@ public:
     long operator()(long i, long j) const {return data_ + i + j;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::packaged_task<double(int, char)> p0(A(5));
@@ -49,4 +49,6 @@ int main()
         assert(!p0.valid());
         assert(!p.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/uses_allocator.pass.cpp b/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/uses_allocator.pass.cpp
index 24727b5d32b..5257a7008cd 100644
--- a/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/uses_allocator.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/uses_allocator.pass.cpp
@@ -27,7 +27,9 @@
 #include <future>
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::uses_allocator<std::packaged_task<double(int, char)>, test_allocator<int> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/copy_assign.fail.cpp b/libcxx/test/std/thread/futures/futures.unique_future/copy_assign.fail.cpp
index 63e92f02140..3a1a4d6be6c 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/copy_assign.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/copy_assign.fail.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -47,4 +47,6 @@ int main()
         f = f0; // expected-error {{'operator=' is a private member of 'std::__1::future<void>'}}
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/copy_ctor.fail.cpp b/libcxx/test/std/thread/futures/futures.unique_future/copy_ctor.fail.cpp
index 0d1a5884b93..4a8b98c1982 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/copy_ctor.fail.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/copy_ctor.fail.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -47,4 +47,6 @@ int main()
         std::future<void> f = f0; // expected-error {{calling a private constructor of class 'std::__1::future<void>'}}
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/default.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/default.pass.cpp
index 0f11aa33407..60ef645e3c9 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/default.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/default.pass.cpp
@@ -17,7 +17,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::future<int> f;
@@ -31,4 +31,6 @@ int main()
         std::future<void> f;
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/dtor.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/dtor.pass.cpp
index 4105d3f9063..ec27219daff 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/dtor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/dtor.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_allocator.h"
 
-int main()
+int main(int, char**)
 {
     assert(test_alloc_base::alloc_count == 0);
     {
@@ -66,4 +66,6 @@ int main()
         assert(f.valid());
     }
     assert(test_alloc_base::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/get.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/get.pass.cpp
index 3d50d896a89..2e3e3264897 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/get.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/get.pass.cpp
@@ -61,7 +61,7 @@ void func6(std::promise<void> p)
     p.set_exception(std::make_exception_ptr('c'));
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -150,4 +150,6 @@ int main()
         }
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/move_assign.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/move_assign.pass.cpp
index 7d2ad6218a2..b0f0e2b5c54 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/move_assign.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/move_assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -70,4 +70,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/move_ctor.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/move_ctor.pass.cpp
index 0b0e4913cf5..aca5dda64f5 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/move_ctor.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/move_ctor.pass.cpp
@@ -17,7 +17,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/share.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/share.pass.cpp
index 392a43a4763..979f93cccf7 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/share.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/share.pass.cpp
@@ -18,7 +18,7 @@
 #include <future>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -71,4 +71,6 @@ int main()
         assert(!f0.valid());
         assert(!f.valid());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp
index 0ec23f27ed0..11fc80868f6 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp
@@ -39,7 +39,7 @@ void func5(std::promise<void> p)
     p.set_value();
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock Clock;
     typedef std::chrono::duration<double, std::milli> ms;
@@ -85,4 +85,6 @@ int main()
         assert(f.valid());
         assert(t1-t0 < ms(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
index 5b8a01aaf16..91f962fd18f 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
@@ -43,7 +43,7 @@ void func5(std::promise<void> p)
     p.set_value();
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock Clock;
     {
@@ -94,4 +94,6 @@ int main()
         assert(f.valid());
         assert(t1-t0 < ms(50));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
index 79da1c0e3ee..28d9b638aed 100644
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
@@ -60,7 +60,7 @@ void func5(std::promise<void> p)
     set_worker_thread_state(WorkerThreadState::Exiting);
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock Clock;
     {
@@ -126,4 +126,6 @@ int main()
         assert(f.valid());
         assert(t1-t0 < ms(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/macro.pass.cpp b/libcxx/test/std/thread/macro.pass.cpp
index bfae0bbee5e..640db4aaa3e 100644
--- a/libcxx/test/std/thread/macro.pass.cpp
+++ b/libcxx/test/std/thread/macro.pass.cpp
@@ -14,9 +14,11 @@
 
 #include <thread>
 
-int main()
+int main(int, char**)
 {
 #ifndef __STDCPP_THREADS__
 #error __STDCPP_THREADS__ is not defined
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/cv_status.pass.cpp b/libcxx/test/std/thread/thread.condition/cv_status.pass.cpp
index af8a10ada41..af980c3eed3 100644
--- a/libcxx/test/std/thread/thread.condition/cv_status.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/cv_status.pass.cpp
@@ -15,8 +15,10 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(static_cast<int>(std::cv_status::no_timeout) == 0);
     assert(static_cast<int>(std::cv_status::timeout)    == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp b/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp
index 22fbc98e2a7..9a0e51e3bfc 100644
--- a/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp
@@ -36,7 +36,7 @@ void func()
     std::this_thread::sleep_for(ms(300));
 }
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex> lk(mut);
     std::thread t(func);
@@ -45,4 +45,6 @@ int main()
     Clock::time_point t1 = Clock::now();
     assert(t1-t0 > ms(250));
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/assign.fail.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/assign.fail.cpp
index e308b20e876..a367051fec3 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/assign.fail.cpp
@@ -15,9 +15,11 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::condition_variable cv0;
     std::condition_variable cv1;
     cv1 = cv0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/copy.fail.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/copy.fail.cpp
index d0c4c653dd3..f9d60765792 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/copy.fail.cpp
@@ -15,8 +15,10 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::condition_variable cv0;
     std::condition_variable cv1(cv0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/default.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/default.pass.cpp
index 879d3c7dcad..aab97f9e14a 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/default.pass.cpp
@@ -17,7 +17,9 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::condition_variable cv;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/destructor.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/destructor.pass.cpp
index 85c83f92ac8..6550109fd79 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/destructor.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/destructor.pass.cpp
@@ -43,7 +43,7 @@ void g()
         cv->wait(lk);
 }
 
-int main()
+int main(int, char**)
 {
     cv = new std::condition_variable;
     std::thread th2(g);
@@ -54,4 +54,6 @@ int main()
     std::thread th1(f);
     th1.join();
     th2.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp
index c281a9d2097..46c53a863f5 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp
@@ -46,7 +46,7 @@ void f2()
     test2 = 2;
 }
 
-int main()
+int main(int, char**)
 {
     std::thread t1(f1);
     std::thread t2(f2);
@@ -65,4 +65,6 @@ int main()
     t2.join();
     assert(test1 == 2);
     assert(test2 == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_one.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_one.pass.cpp
index f72d36e8abf..eb1de67db9f 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_one.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_one.pass.cpp
@@ -47,7 +47,7 @@ void f2()
     test2 = 2;
 }
 
-int main()
+int main(int, char**)
 {
     std::thread t1(f1);
     std::thread t2(f2);
@@ -95,4 +95,6 @@ int main()
     }
     else
         assert(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait.pass.cpp
index a3420740641..03bcfeea94d 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait.pass.cpp
@@ -36,7 +36,7 @@ void f()
     assert(test2 != 0);
 }
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex>lk(mut);
     std::thread t(f);
@@ -48,4 +48,6 @@ int main()
     lk.unlock();
     cv.notify_one();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
index f34b230c243..505997fff46 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
@@ -59,7 +59,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_lock<std::mutex>lk(mut);
@@ -85,4 +85,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
index a61b000bdc9..e92ce4583c5 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
@@ -66,7 +66,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_lock<std::mutex>lk(mut);
@@ -92,4 +92,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_pred.pass.cpp
index f99436a5e29..0de8524ed1e 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_pred.pass.cpp
@@ -46,7 +46,7 @@ void f()
     assert(test2 != 0);
 }
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex>lk(mut);
     std::thread t(f);
@@ -58,4 +58,6 @@ int main()
     lk.unlock();
     cv.notify_one();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp
index f954ae25ee2..7f1bdf827cb 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp
@@ -72,7 +72,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_lock<std::mutex>lk(mut);
@@ -98,4 +98,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp
index 8307a52c0e3..f21b1b54bc6 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp
@@ -85,7 +85,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_lock<std::mutex>lk(mut);
@@ -111,4 +111,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/assign.fail.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/assign.fail.cpp
index 214164ea72a..0c2adc9a538 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/assign.fail.cpp
@@ -15,9 +15,11 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::condition_variable_any cv0;
     std::condition_variable_any cv1;
     cv1 = cv0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/copy.fail.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/copy.fail.cpp
index 6eafc62024f..5aff93ba0fa 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/copy.fail.cpp
@@ -15,8 +15,10 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::condition_variable_any cv0;
     std::condition_variable_any cv1(cv0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/default.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/default.pass.cpp
index 05ebff06807..0c35da0321b 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/default.pass.cpp
@@ -17,7 +17,9 @@
 #include <condition_variable>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::condition_variable_any cv;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/destructor.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/destructor.pass.cpp
index 57b3024fe0a..35580d4293b 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/destructor.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/destructor.pass.cpp
@@ -44,7 +44,7 @@ void g()
     m.unlock();
 }
 
-int main()
+int main(int, char**)
 {
     cv = new std::condition_variable_any;
     std::thread th2(g);
@@ -55,4 +55,6 @@ int main()
     std::thread th1(f);
     th1.join();
     th2.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_all.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_all.pass.cpp
index cb79d8a6b6c..d12c9360288 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_all.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_all.pass.cpp
@@ -50,7 +50,7 @@ void f2()
     test2 = 2;
 }
 
-int main()
+int main(int, char**)
 {
     std::thread t1(f1);
     std::thread t2(f2);
@@ -69,4 +69,6 @@ int main()
     t2.join();
     assert(test1 == 2);
     assert(test2 == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
index e5c0a0943c9..27a0f87e59f 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
@@ -52,7 +52,7 @@ void f2()
     test2 = 2;
 }
 
-int main()
+int main(int, char**)
 {
     std::thread t1(f1);
     std::thread t2(f2);
@@ -96,4 +96,6 @@ int main()
     }
     else
         assert(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait.pass.cpp
index 741094bddfa..a3b2e87c9e9 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait.pass.cpp
@@ -41,7 +41,7 @@ void f()
     assert(test2 != 0);
 }
 
-int main()
+int main(int, char**)
 {
     L1 lk(m0);
     std::thread t(f);
@@ -53,4 +53,6 @@ int main()
     lk.unlock();
     cv.notify_one();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp
index ec4eb339896..d472a698fec 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp
@@ -62,7 +62,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         L1 lk(m0);
@@ -88,4 +88,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp
index 81d69861fe9..cbf0193ade3 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp
@@ -70,7 +70,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         expect_result = true;
@@ -98,4 +98,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_pred.pass.cpp
index d76cbd443a9..eafc434d0c2 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_pred.pass.cpp
@@ -50,7 +50,7 @@ void f()
     assert(test2 != 0);
 }
 
-int main()
+int main(int, char**)
 {
     L1 lk(m0);
     std::thread t(f);
@@ -62,4 +62,6 @@ int main()
     lk.unlock();
     cv.notify_one();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp
index 796b66e99b6..8afa0515920 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp
@@ -109,7 +109,7 @@ void signal_me() {
 typedef std::chrono::system_clock Clock;
 typedef std::chrono::milliseconds MS;
 
-int main(int argc, char** argv) {
+int main(int argc, char **argv) {
   assert(argc == 2);
   int id = std::stoi(argv[1]);
   assert(id >= 1 && id <= 6);
@@ -130,4 +130,6 @@ int main(int argc, char** argv) {
     }
   } catch (...) {}
   assert(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp
index 276597350f6..e14944906b7 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp
@@ -75,7 +75,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         L1 lk(m0);
@@ -101,4 +101,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp
index 0216688d7e2..5eb253a75fc 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp
@@ -89,7 +89,7 @@ void f()
     ++runs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         L1 lk(m0);
@@ -115,4 +115,6 @@ int main()
         lk.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.general/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/lock.pass.cpp
index 1c7de834940..207b0753e72 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/lock.pass.cpp
@@ -92,7 +92,7 @@ public:
     bool locked() const {return locked_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         L0 l0;
@@ -518,4 +518,6 @@ int main()
     }
 #endif  // TEST_HAS_NO_EXCEPTIONS
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/try_lock.pass.cpp
index 7856ab96f8b..50ff29ce959 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock.algorithm/try_lock.pass.cpp
@@ -72,7 +72,7 @@ public:
     bool locked() const {return locked_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         L0 l0;
@@ -522,4 +522,6 @@ int main()
         assert(!l3.locked());
     }
 #endif  // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/adopt_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/adopt_lock.pass.cpp
index 273a4881355..fc76eb34eb4 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/adopt_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/adopt_lock.pass.cpp
@@ -42,11 +42,13 @@ void f()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/assign.fail.cpp
index b22e0db9efd..2d0f438ed03 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/assign.fail.cpp
@@ -14,11 +14,13 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::mutex m0;
     std::mutex m1;
     std::lock_guard<std::mutex> lg0(m0);
     std::lock_guard<std::mutex> lg(m1);
     lg = lg0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/copy.fail.cpp
index 1852db1e5a0..e99517e47e8 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/copy.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::mutex m;
     std::lock_guard<std::mutex> lg0(m);
     std::lock_guard<std::mutex> lg(lg0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.fail.cpp
index 52a0397de55..383c1539a60 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.fail.cpp
@@ -16,8 +16,10 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::mutex m;
     std::lock_guard<std::mutex> lg = m; // expected-error{{no viable conversion}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp
index 84353486bac..fa6aa4615aa 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp
@@ -46,7 +46,7 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
@@ -58,4 +58,6 @@ int main()
     std::lock_guard lg(m);
     static_assert((std::is_same<decltype(lg), std::lock_guard<decltype(m)>>::value), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/types.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/types.pass.cpp
index 745633b55c7..b9cdb4dec5d 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/types.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/types.pass.cpp
@@ -21,8 +21,10 @@
 #include <mutex>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::lock_guard<std::mutex>::mutex_type,
                    std::mutex>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/adopt_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/adopt_lock.pass.cpp
index edaf09c5a1d..63e0626d532 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/adopt_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/adopt_lock.pass.cpp
@@ -31,7 +31,7 @@ struct TestMutex {
     TestMutex& operator=(TestMutex const&) = delete;
 };
 
-int main()
+int main(int, char**)
 {
     {
         using LG = std::scoped_lock<>;
@@ -68,4 +68,6 @@ int main()
         assert(!m1.locked && !m2.locked && !m3.locked);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/assign.fail.cpp
index d88b4dedc93..66a68bb2765 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/assign.fail.cpp
@@ -18,7 +18,7 @@
 #include <mutex>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using M = std::mutex;
     M m0, m1, m2;
@@ -46,4 +46,6 @@ int main()
         LG lg2(om0, om1, om2);
         lg1 = lg2; // expected-error{{overload resolution selected deleted operator '='}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/copy.fail.cpp
index 16938731b7b..3829d15a625 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/copy.fail.cpp
@@ -18,7 +18,7 @@
 #include <mutex>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using M = std::mutex;
     M m0, m1, m2;
@@ -42,4 +42,6 @@ int main()
         const LG Orig(m0, m1, m2);
         LG Copy(Orig); // expected-error{{call to deleted constructor of 'LG'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.fail.cpp
index 4f25ec237aa..0c9258887d3 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.fail.cpp
@@ -21,7 +21,7 @@
 template <class LG>
 void test_conversion(LG) {}
 
-int main()
+int main(int, char**)
 {
     using M = std::mutex;
     M m0, m1, m2;
@@ -49,4 +49,6 @@ int main()
         LG lg = {m0, m1, m2}; // expected-error{{chosen constructor is explicit in copy-initialization}}
         test_conversion<LG>({n0, n1, n2}); // expected-error{{no matching function for call}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.pass.cpp
index 219c389aa02..3a633c39b03 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/mutex.pass.cpp
@@ -61,7 +61,7 @@ struct TestMutexThrows {
 };
 #endif // !defined(TEST_HAS_NO_EXCEPTIONS)
 
-int main()
+int main(int, char**)
 {
     {
         using LG = std::scoped_lock<>;
@@ -151,4 +151,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp
index 5228ccead87..62621fccad7 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp
@@ -36,7 +36,7 @@ constexpr bool has_mutex_type() {
     return !std::is_same<decltype(test_typedef<LG>(0)), NAT>::value;
 }
 
-int main()
+int main(int, char**)
 {
     {
         using T = std::scoped_lock<>;
@@ -74,4 +74,6 @@ int main()
         using T = std::scoped_lock<M1, M1, M1>;
         static_assert(!has_mutex_type<T>(), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_assign.fail.cpp
index ff6c376da2c..1b31fbc50d2 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_assign.fail.cpp
@@ -18,9 +18,11 @@
 std::shared_timed_mutex m0;
 std::shared_timed_mutex m1;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<std::shared_timed_mutex> lk0(m0);
     std::shared_lock<std::shared_timed_mutex> lk1(m1);
     lk1 = lk0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_ctor.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_ctor.fail.cpp
index 6f1f2e9ab04..48da3c715fa 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_ctor.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/copy_ctor.fail.cpp
@@ -17,8 +17,10 @@
 
 std::shared_timed_mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<std::shared_timed_mutex> lk0(m);
     std::shared_lock<std::shared_timed_mutex> lk = lk0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/default.pass.cpp
index 2d571cb51db..0543ae72e82 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/default.pass.cpp
@@ -18,9 +18,11 @@
 #include <shared_mutex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<std::shared_timed_mutex> ul;
     assert(!ul.owns_lock());
     assert(ul.mutex() == nullptr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_assign.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_assign.pass.cpp
index 960948421d2..999d65f028b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_assign.pass.cpp
@@ -20,7 +20,7 @@
 #include "nasty_containers.hpp"
 
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::shared_timed_mutex M;
@@ -46,4 +46,6 @@ int main()
     assert(lk0.mutex() == nullptr);
     assert(lk0.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_ctor.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_ctor.pass.cpp
index 6be2e774b00..1f61e21fbcf 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_ctor.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/move_ctor.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::shared_timed_mutex M;
@@ -41,4 +41,6 @@ int main()
     assert(lk0.mutex() == nullptr);
     assert(lk0.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
index 1204eb1f018..14c084f008d 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
@@ -71,7 +71,7 @@ void g()
     assert(d < Tolerance);  // within tolerance
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<std::thread> v;
     {
@@ -99,4 +99,6 @@ int main()
     std::shared_lock sl(m);
     static_assert((std::is_same<decltype(sl), std::shared_lock<decltype(m)>>::value), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_adopt_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_adopt_lock.pass.cpp
index 2b5fae21bdc..86d54b5083b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_adopt_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_adopt_lock.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::shared_timed_mutex M;
@@ -37,4 +37,6 @@ int main()
     assert(lk.mutex() == std::addressof(m));
     assert(lk.owns_lock() == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_defer_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_defer_lock.pass.cpp
index c7d0a192b79..5a085d2e6ae 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_defer_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_defer_lock.pass.cpp
@@ -19,7 +19,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::shared_timed_mutex M;
@@ -35,4 +35,6 @@ int main()
     assert(lk.mutex() == std::addressof(m));
     assert(lk.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
index f633c2e8c65..3228f938f90 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
@@ -66,7 +66,7 @@ void f2()
     assert(d < Tolerance);  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -88,4 +88,6 @@ int main()
         for (auto& t : v)
             t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
index c899cea3e04..f62e739443a 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
@@ -65,7 +65,7 @@ void f2()
     assert(d < Tolerance);  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -87,4 +87,6 @@ int main()
         for (auto& t : v)
             t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
index 4375a2b9978..7dd7c16fe5b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
@@ -57,7 +57,7 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::vector<std::thread> v;
@@ -67,4 +67,6 @@ int main()
     m.unlock();
     for (auto& t : v)
         t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
index 7726337c8c7..5f084b21259 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
@@ -80,7 +80,7 @@ void f()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::vector<std::thread> v;
@@ -90,4 +90,6 @@ int main()
     m.unlock();
     for (auto& t : v)
         t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp
index 884dd47b092..488260618bc 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp
@@ -34,7 +34,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<mutex> lk(m, std::defer_lock);
     assert(lk.try_lock() == true);
@@ -67,4 +67,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_for.pass.cpp
index e6df4f121f3..b2c1776839b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_for.pass.cpp
@@ -39,7 +39,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<mutex> lk(m, std::defer_lock);
     assert(lk.try_lock_for(ms(5)) == true);
@@ -72,4 +72,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp
index 74e0ecc23e7..59bcd4a0bd8 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp
@@ -38,7 +38,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::steady_clock Clock;
     std::shared_lock<mutex> lk(m, std::defer_lock);
@@ -72,4 +72,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/unlock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/unlock.pass.cpp
index 6c100470e34..b0e337bda5f 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/unlock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/unlock.pass.cpp
@@ -30,7 +30,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<mutex> lk(m);
     lk.unlock();
@@ -59,4 +59,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/member_swap.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/member_swap.pass.cpp
index 22eb3ee48e6..ce385ddbd66 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/member_swap.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/member_swap.pass.cpp
@@ -26,7 +26,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<mutex> lk1(m);
     std::shared_lock<mutex> lk2;
@@ -36,4 +36,6 @@ int main()
     assert(lk2.mutex() == &m);
     assert(lk2.owns_lock() == true);
     static_assert(noexcept(lk1.swap(lk2)), "member swap must be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/nonmember_swap.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/nonmember_swap.pass.cpp
index 65e05d39f5c..cec13f0f2f7 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/nonmember_swap.pass.cpp
@@ -27,7 +27,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<mutex> lk1(m);
     std::shared_lock<mutex> lk2;
@@ -37,4 +37,6 @@ int main()
     assert(lk2.mutex() == &m);
     assert(lk2.owns_lock() == true);
     static_assert(noexcept(swap(lk1, lk2)), "non-member swap must be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/release.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/release.pass.cpp
index d387a835180..f2e5820cf0c 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/release.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.mod/release.pass.cpp
@@ -31,7 +31,7 @@ int mutex::unlock_count = 0;
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<mutex> lk(m);
     assert(lk.mutex() == &m);
@@ -44,4 +44,6 @@ int main()
     assert(mutex::lock_count == 1);
     assert(mutex::unlock_count == 0);
     static_assert(noexcept(lk.release()), "release must be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/mutex.pass.cpp
index 28685954ba7..867bae0e371 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/mutex.pass.cpp
@@ -20,7 +20,7 @@
 
 std::shared_timed_mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<std::shared_timed_mutex> lk0;
     assert(lk0.mutex() == nullptr);
@@ -29,4 +29,6 @@ int main()
     lk1.unlock();
     assert(lk1.mutex() == &m);
     static_assert(noexcept(lk0.mutex()), "mutex() must be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/op_bool.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/op_bool.pass.cpp
index 1064d727c69..82d737ee5e5 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/op_bool.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/op_bool.pass.cpp
@@ -20,7 +20,7 @@
 
 std::shared_timed_mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<std::shared_timed_mutex> lk0;
     assert(static_cast<bool>(lk0) == false);
@@ -29,4 +29,6 @@ int main()
     lk1.unlock();
     assert(static_cast<bool>(lk1) == false);
     static_assert(noexcept(static_cast<bool>(lk0)), "explicit operator bool() must be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/owns_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/owns_lock.pass.cpp
index 36a2c0f835d..f949684e834 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/owns_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/owns_lock.pass.cpp
@@ -20,7 +20,7 @@
 
 std::shared_timed_mutex m;
 
-int main()
+int main(int, char**)
 {
     std::shared_lock<std::shared_timed_mutex> lk0;
     assert(lk0.owns_lock() == false);
@@ -29,4 +29,6 @@ int main()
     lk1.unlock();
     assert(lk1.owns_lock() == false);
     static_assert(noexcept(lk0.owns_lock()), "owns_lock must be noexcept");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/types.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/types.pass.cpp
index c5be52afea2..44d19e8dbb4 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/types.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/types.pass.cpp
@@ -23,8 +23,10 @@
 #include <shared_mutex>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::shared_lock<std::mutex>::mutex_type,
                    std::mutex>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_assign.fail.cpp
index 05799104657..799cb61f9b2 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_assign.fail.cpp
@@ -15,7 +15,7 @@
 #include <mutex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::mutex M;
@@ -29,4 +29,6 @@ int main()
     assert(lk0.mutex() == nullptr);
     assert(lk0.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_ctor.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_ctor.fail.cpp
index 12045f9989d..e258198e60b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_ctor.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/copy_ctor.fail.cpp
@@ -15,7 +15,7 @@
 #include <mutex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::mutex M;
@@ -27,4 +27,6 @@ int main()
     assert(lk0.mutex() == nullptr);
     assert(lk0.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/default.pass.cpp
index 46f4f1e8013..74b26514102 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/default.pass.cpp
@@ -17,9 +17,11 @@
 #include <mutex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex> ul;
     assert(!ul.owns_lock());
     assert(ul.mutex() == nullptr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_assign.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_assign.pass.cpp
index 16b1bd8c554..1e663766b10 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_assign.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_assign.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::mutex M;
@@ -44,4 +44,6 @@ int main()
     assert(lk0.mutex() == nullptr);
     assert(lk0.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_ctor.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_ctor.pass.cpp
index 2c4993702b1..8ea0a1f2d46 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_ctor.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/move_ctor.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::mutex M;
@@ -40,4 +40,6 @@ int main()
     assert(lk0.mutex() == nullptr);
     assert(lk0.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
index 30897b3d862..61c0dacf17a 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
@@ -46,7 +46,7 @@ void f()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
@@ -58,4 +58,6 @@ int main()
     std::unique_lock ul(m);
     static_assert((std::is_same<decltype(ul), std::unique_lock<decltype(m)>>::value), "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_adopt_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_adopt_lock.pass.cpp
index 1c258d6a64a..d957c6d24b0 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_adopt_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_adopt_lock.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::mutex M;
@@ -36,4 +36,6 @@ int main()
     assert(lk.mutex() == std::addressof(m));
     assert(lk.owns_lock() == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_defer_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_defer_lock.pass.cpp
index 5f4ab4e7413..af6853160f6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_defer_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_defer_lock.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "nasty_containers.hpp"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::mutex M;
@@ -34,4 +34,6 @@ int main()
     assert(lk.mutex() == std::addressof(m));
     assert(lk.owns_lock() == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp
index 8fee76b8fe7..8699dd554af 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp
@@ -50,7 +50,7 @@ void f2()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -66,4 +66,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp
index 4cd2efeba2b..ab46dacad3c 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp
@@ -50,7 +50,7 @@ void f2()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -66,4 +66,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp
index 3c385808bf3..448be8e7e14 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp
@@ -53,11 +53,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
index 536a0d7d22c..b8a0c2d343e 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
@@ -66,11 +66,13 @@ void f()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock.pass.cpp
index cfc0befcab1..a6247df7ede 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock.pass.cpp
@@ -33,7 +33,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<mutex> lk(m, std::defer_lock);
     assert(lk.try_lock() == true);
@@ -66,4 +66,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_for.pass.cpp
index f1a2ef6c414..a6166ceda86 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_for.pass.cpp
@@ -38,7 +38,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<mutex> lk(m, std::defer_lock);
     assert(lk.try_lock_for(ms(5)) == true);
@@ -71,4 +71,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp
index 60616da935f..6c7da1c0cdf 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp
@@ -37,7 +37,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::steady_clock Clock;
     std::unique_lock<mutex> lk(m, std::defer_lock);
@@ -71,4 +71,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/unlock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/unlock.pass.cpp
index bb0c00ded28..1f0a0e529dc 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/unlock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/unlock.pass.cpp
@@ -29,7 +29,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<mutex> lk(m);
     lk.unlock();
@@ -58,4 +58,6 @@ int main()
         assert(e.code().value() == EPERM);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/member_swap.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/member_swap.pass.cpp
index 3c89d6cf8e0..707755f59a8 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/member_swap.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/member_swap.pass.cpp
@@ -25,7 +25,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<mutex> lk1(m);
     std::unique_lock<mutex> lk2;
@@ -34,4 +34,6 @@ int main()
     assert(lk1.owns_lock() == false);
     assert(lk2.mutex() == &m);
     assert(lk2.owns_lock() == true);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/nonmember_swap.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/nonmember_swap.pass.cpp
index ea99ba9e5ff..1c05657d6ba 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/nonmember_swap.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/nonmember_swap.pass.cpp
@@ -26,7 +26,7 @@ struct mutex
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<mutex> lk1(m);
     std::unique_lock<mutex> lk2;
@@ -35,4 +35,6 @@ int main()
     assert(lk1.owns_lock() == false);
     assert(lk2.mutex() == &m);
     assert(lk2.owns_lock() == true);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/release.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/release.pass.cpp
index 9dc9ec3a1ab..9751149b9bd 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/release.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.mod/release.pass.cpp
@@ -30,7 +30,7 @@ int mutex::unlock_count = 0;
 
 mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<mutex> lk(m);
     assert(lk.mutex() == &m);
@@ -42,4 +42,6 @@ int main()
     assert(lk.owns_lock() == false);
     assert(mutex::lock_count == 1);
     assert(mutex::unlock_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/mutex.pass.cpp
index 6e6fb6b76ff..899f965dfe1 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/mutex.pass.cpp
@@ -19,7 +19,7 @@
 
 std::mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex> lk0;
     assert(lk0.mutex() == nullptr);
@@ -27,4 +27,6 @@ int main()
     assert(lk1.mutex() == &m);
     lk1.unlock();
     assert(lk1.mutex() == &m);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp
index 184bc71f5b7..1affe8deb19 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp
@@ -19,7 +19,7 @@
 
 std::mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex> lk0;
     assert(static_cast<bool>(lk0) == false);
@@ -27,4 +27,6 @@ int main()
     assert(static_cast<bool>(lk1) == true);
     lk1.unlock();
     assert(static_cast<bool>(lk1) == false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/owns_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/owns_lock.pass.cpp
index 68f944e2663..2c5496b294b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/owns_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/owns_lock.pass.cpp
@@ -19,7 +19,7 @@
 
 std::mutex m;
 
-int main()
+int main(int, char**)
 {
     std::unique_lock<std::mutex> lk0;
     assert(lk0.owns_lock() == false);
@@ -27,4 +27,6 @@ int main()
     assert(lk1.owns_lock() == true);
     lk1.unlock();
     assert(lk1.owns_lock() == false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/types.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/types.pass.cpp
index 44b1265e7ea..7dc093ac639 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/types.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/types.pass.cpp
@@ -21,8 +21,10 @@
 #include <mutex>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::unique_lock<std::mutex>::mutex_type,
                    std::mutex>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/types.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/types.pass.cpp
index 8d6a1fbcef9..150d9b4aafc 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/types.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/types.pass.cpp
@@ -21,7 +21,7 @@
 #include <mutex>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::defer_lock_t T1;
     typedef std::try_to_lock_t T2;
@@ -30,4 +30,6 @@ int main()
     T1 t1 = std::defer_lock; ((void)t1);
     T2 t2 = std::try_to_lock; ((void)t2);
     T3 t3 = std::adopt_lock; ((void)t3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.general/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/assign.fail.cpp
index d2d34a289ea..ba09ed1a706 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/assign.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::mutex m0;
     std::mutex m1;
     m1 = m0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/copy.fail.cpp
index 5e1f17dc186..9edfb7267de 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/copy.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::mutex m0;
     std::mutex m1(m0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/default.pass.cpp
index aa8a34b0735..b5a608eeb0c 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/default.pass.cpp
@@ -17,8 +17,10 @@
 #include <mutex>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_nothrow_default_constructible<std::mutex>::value, "");
     std::mutex m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp
index 912b647d3d2..dcb4b8ff859 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp
@@ -41,11 +41,13 @@ void f()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp
index 9d3d53dab31..71221558331 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp
@@ -41,11 +41,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/assign.fail.cpp
index 613eae74de5..0cf3c5bca1e 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/assign.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::recursive_mutex m0;
     std::recursive_mutex m1;
     m1 = m0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/copy.fail.cpp
index 812951b46ec..454d7797373 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/copy.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::recursive_mutex m0;
     std::recursive_mutex m1(m0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/default.pass.cpp
index 9c63a803703..e32c92f0c97 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/default.pass.cpp
@@ -16,7 +16,9 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::recursive_mutex m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp
index 0342b4c2cf2..f8744a9b750 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp
@@ -41,11 +41,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp
index b5b256566f7..092343fe752 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp
@@ -43,11 +43,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/assign.fail.cpp
index 6b589f97d97..337fcdf08b4 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/assign.fail.cpp
@@ -17,9 +17,11 @@
 
 #include <shared_mutex>
 
-int main()
+int main(int, char**)
 {
     std::shared_mutex m0;
     std::shared_mutex m1;
     m1 = m0; // expected-error {{overload resolution selected deleted operator '='}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/copy.fail.cpp
index 0c4fb55f14a..93d02885a59 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/copy.fail.cpp
@@ -17,8 +17,10 @@
 
 #include <shared_mutex>
 
-int main()
+int main(int, char**)
 {
     std::shared_mutex m0;
     std::shared_mutex m1(m0); // expected-error {{call to deleted constructor of 'std::shared_mutex'}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/default.pass.cpp
index ac8b9b076cb..ecd29b7485a 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/default.pass.cpp
@@ -17,7 +17,9 @@
 
 #include <shared_mutex>
 
-int main()
+int main(int, char**)
 {
     std::shared_mutex m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp
index 3eb434a8034..74c66d0f672 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp
@@ -53,11 +53,13 @@ void f()
     assert(d < Tolerance);  // within tolerance
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(WaitTime);
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp
index 38be785c867..7707af8d8b8 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp
@@ -65,7 +65,7 @@ void g()
 }
 
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::vector<std::thread> v;
@@ -84,4 +84,6 @@ int main()
     for (auto& t : v)
         t.join();
     q.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp
index fff58b1ff72..09c7ad5f005 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp
@@ -42,11 +42,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp
index 26bf18868f6..b9538b56497 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp
@@ -46,7 +46,7 @@ void f()
 }
 
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::vector<std::thread> v;
@@ -56,4 +56,6 @@ int main()
     m.unlock();
     for (auto& t : v)
         t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/assign.fail.cpp
index c710e0510f7..483111db97e 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/assign.fail.cpp
@@ -15,9 +15,11 @@
 
 #include <shared_mutex>
 
-int main()
+int main(int, char**)
 {
     std::shared_timed_mutex m0;
     std::shared_timed_mutex m1;
     m1 = m0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/copy.fail.cpp
index dba5e311417..7483b1f5193 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/copy.fail.cpp
@@ -15,8 +15,10 @@
 
 #include <shared_mutex>
 
-int main()
+int main(int, char**)
 {
     std::shared_timed_mutex m0;
     std::shared_timed_mutex m1(m0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/default.pass.cpp
index 8fe432fc191..83b30b98dd9 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/default.pass.cpp
@@ -17,7 +17,9 @@
 
 #include <shared_mutex>
 
-int main()
+int main(int, char**)
 {
     std::shared_timed_mutex m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
index c3be2b61663..56464b24005 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
@@ -55,11 +55,13 @@ void f()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
index 0702ba01c07..08d35861e47 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
@@ -67,7 +67,7 @@ void g()
 }
 
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::vector<std::thread> v;
@@ -86,4 +86,6 @@ int main()
     for (auto& t : v)
         t.join();
     q.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp
index 4927c3654b7..6b2d9a543e5 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp
@@ -42,11 +42,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp
index d2a24fb81ca..45fea3e96fc 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp
@@ -64,7 +64,7 @@ void f2()
     assert(d < Tolerance);  // within tolerance
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -80,4 +80,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp
index 7e0886de447..830445af9a0 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp
@@ -54,7 +54,7 @@ void f()
     assert(d < Tolerance);  // within tolerance
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::vector<std::thread> v;
@@ -64,4 +64,6 @@ int main()
     m.unlock();
     for (auto& t : v)
         t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp
index 250ff9be932..d89e4aa8cfc 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp
@@ -64,7 +64,7 @@ void f2()
     assert(d < Tolerance);  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -86,4 +86,6 @@ int main()
         for (auto& t : v)
             t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
index de6c5846387..5898fe41e05 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
@@ -64,7 +64,7 @@ void f2()
     assert(d < Tolerance);  // within tolerance
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -86,4 +86,6 @@ int main()
         for (auto& t : v)
             t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp
index 40cdfe84400..9539215c46f 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp
@@ -64,7 +64,7 @@ void f2()
     assert(d < Tolerance);  // within tolerance
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -80,4 +80,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp
index fb766e1617a..865ab92545a 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp
@@ -47,7 +47,7 @@ void blocked_reader() {
   m.unlock_shared();
 }
 
-int main()
+int main(int, char**)
 {
   typedef std::chrono::steady_clock Clock;
 
@@ -66,4 +66,6 @@ int main()
   t1.join();
   t2.join();
   t3.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/assign.fail.cpp
index 902b5ec42a6..d0fabc678f2 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/assign.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::timed_mutex m0;
     std::timed_mutex m1;
     m1 = m0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/copy.fail.cpp
index 803b330d6a9..a3efb2feeee 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/copy.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::timed_mutex m0;
     std::timed_mutex m1(m0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/default.pass.cpp
index aae979043bf..c879f192ee1 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/default.pass.cpp
@@ -16,7 +16,9 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::timed_mutex m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp
index 7b351829ab4..8ef3a83471b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp
@@ -39,11 +39,13 @@ void f()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp
index d61f62635e8..7398b7f6d0b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp
@@ -41,11 +41,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp
index 2e050d91702..0103cdf6419 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp
@@ -47,7 +47,7 @@ void f2()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -63,4 +63,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp
index adf711593c4..350bb767d48 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp
@@ -47,7 +47,7 @@ void f2()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -63,4 +63,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/assign.fail.cpp
index e34b2b9980a..44be06d6754 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/assign.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::recursive_timed_mutex m0;
     std::recursive_timed_mutex m1;
     m1 = m0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/copy.fail.cpp
index cbdd2eb634a..154a0192d14 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/copy.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::recursive_timed_mutex m0;
     std::recursive_timed_mutex m1(m0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/default.pass.cpp
index 98de22eccc8..ee6124c027b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/default.pass.cpp
@@ -16,7 +16,9 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::recursive_timed_mutex m;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp
index aba747b9520..adb54872e9b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp
@@ -43,11 +43,13 @@ void f()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp
index 9d73bb57f33..05b22c0deb1 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp
@@ -43,11 +43,13 @@ void f()
     assert(d < ms(200));  // within 200ms
 }
 
-int main()
+int main(int, char**)
 {
     m.lock();
     std::thread t(f);
     std::this_thread::sleep_for(ms(250));
     m.unlock();
     t.join();
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp
index feab814953b..9e5ad5ee9a5 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp
@@ -49,7 +49,7 @@ void f2()
     assert(d < ns(50000000));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -65,4 +65,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp
index b795315b28d..f6b9d106a1b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp
@@ -49,7 +49,7 @@ void f2()
     assert(d < ms(50));  // within 50ms
 }
 
-int main()
+int main(int, char**)
 {
     {
         m.lock();
@@ -65,4 +65,6 @@ int main()
         m.unlock();
         t.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.once/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.once/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.once/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.once/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/call_once.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/call_once.pass.cpp
index be5056e40f7..398ee058c12 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/call_once.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/call_once.pass.cpp
@@ -186,7 +186,7 @@ struct RefQual
 
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     // check basic functionality
     {
@@ -253,4 +253,6 @@ int main()
         assert(rq.rv_called == 1);
     }
 #endif  // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/race.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/race.pass.cpp
index ebba7f3d4f4..511aa3e804b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/race.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.callonce/race.pass.cpp
@@ -37,11 +37,13 @@ void f0()
     assert(global == 1);
 }
 
-int main()
+int main(int, char**)
 {
     std::thread t0(f0);
     std::thread t1(f0);
     t0.join();
     t1.join();
     assert(global == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/assign.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/assign.fail.cpp
index dd6fe09c3b8..40d408d54ce 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/assign.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/assign.fail.cpp
@@ -14,9 +14,11 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::once_flag f;
     std::once_flag f2;
     f2 = f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/copy.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/copy.fail.cpp
index ca428ffb438..9b7c19a9672 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/copy.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <mutex>
 
-int main()
+int main(int, char**)
 {
     std::once_flag f;
     std::once_flag f2(f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/default.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/default.pass.cpp
index 4a1655ffeba..28d93dc7f38 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.once/thread.once.onceflag/default.pass.cpp
@@ -15,7 +15,7 @@
 #include <mutex>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::once_flag f;
@@ -27,4 +27,6 @@ int main()
     (void)f;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.exception/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.exception/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.exception/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.exception/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.lockable/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.lockable/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.lockable/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.lockable/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.basic/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.basic/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.basic/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.basic/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.general/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.req/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.req/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.req/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.timed/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.timed/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.timed/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.lockable/thread.req.lockable.timed/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.native/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.native/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.native/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.native/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.paramname/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.paramname/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.paramname/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.paramname/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.req/thread.req.timing/nothing_to_do.pass.cpp b/libcxx/test/std/thread/thread.req/thread.req.timing/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/thread/thread.req/thread.req.timing/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/thread/thread.req/thread.req.timing/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.algorithm/swap.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.algorithm/swap.pass.cpp
index 64a41368627..68f20d7532b 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.algorithm/swap.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.algorithm/swap.pass.cpp
@@ -41,7 +41,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -54,4 +54,6 @@ int main()
         assert(t1.get_id() == id0);
         t1.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/copy.fail.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/copy.fail.cpp
index 1afaaf7bd61..e67ceea5db6 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/copy.fail.cpp
@@ -40,11 +40,13 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         std::thread t0(G());
         std::thread t1;
         t1 = t0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move.pass.cpp
index e2f3d38fc06..cbc32c8c2ce 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move.pass.cpp
@@ -41,7 +41,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         assert(G::n_alive == 0);
@@ -59,4 +59,6 @@ int main()
         assert(G::n_alive == 0);
         assert(G::op_run);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move2.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move2.pass.cpp
index 9a4d6e91020..81c6d77e8a7 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move2.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.assign/move2.pass.cpp
@@ -51,7 +51,7 @@ void f1()
     std::_Exit(0);
 }
 
-int main()
+int main(int, char**)
 {
     std::set_terminate(f1);
     {
@@ -61,4 +61,6 @@ int main()
         t0 = std::move(t1);
         assert(false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/F.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/F.pass.cpp
index af2450f182f..13c69180a4d 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/F.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/F.pass.cpp
@@ -144,7 +144,7 @@ void test_throwing_new_during_thread_creation() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_throwing_new_during_thread_creation();
     {
@@ -200,4 +200,6 @@ int main()
         t.join();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/constr.fail.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/constr.fail.cpp
index c24b0413b20..26231373f80 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/constr.fail.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/constr.fail.cpp
@@ -18,8 +18,10 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     volatile std::thread t1;
     std::thread t2 ( t1, 1, 2.0 );
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/copy.fail.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/copy.fail.cpp
index 4a2e6f0d44b..2a3632cd42f 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/copy.fail.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/copy.fail.cpp
@@ -48,7 +48,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         assert(G::n_alive == 0);
@@ -62,4 +62,6 @@ int main()
         assert(G::n_alive == 0);
         assert(G::op_run);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/default.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/default.pass.cpp
index d635470db31..135d3ceba99 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/default.pass.cpp
@@ -17,8 +17,10 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread t;
     assert(t.get_id() == std::thread::id());
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/move.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/move.pass.cpp
index 7e34729b3a7..25703b2c3ca 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/move.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/move.pass.cpp
@@ -50,7 +50,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -66,4 +66,6 @@ int main()
         assert(G::op_run);
     }
     assert(G::n_alive == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.destr/dtor.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.destr/dtor.pass.cpp
index 202d61b8f22..320b4459b94 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.destr/dtor.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.destr/dtor.pass.cpp
@@ -47,7 +47,7 @@ void f1()
     std::_Exit(0);
 }
 
-int main()
+int main(int, char**)
 {
     std::set_terminate(f1);
     {
@@ -60,4 +60,6 @@ int main()
         }
     }
     assert(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/assign.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/assign.pass.cpp
index 4447600486a..fb4b7eb5ae0 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/assign.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/assign.pass.cpp
@@ -17,7 +17,7 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id0;
     std::thread::id id1;
@@ -25,4 +25,6 @@ int main()
     assert(id1 == id0);
     id1 = std::this_thread::get_id();
     assert(id1 != id0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/copy.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/copy.pass.cpp
index 52d4f2cf377..f95617b4f53 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/copy.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/copy.pass.cpp
@@ -17,9 +17,11 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id0;
     std::thread::id id1 = id0;
     assert(id1 == id0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/default.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/default.pass.cpp
index a9778f047d2..32a083ca8aa 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/default.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/default.pass.cpp
@@ -17,8 +17,10 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id;
     assert(id == std::thread::id());
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/enabled_hashes.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/enabled_hashes.pass.cpp
index 7a2fa869d62..3858508e1c9 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/enabled_hashes.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/enabled_hashes.pass.cpp
@@ -18,9 +18,11 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::thread::id>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/eq.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/eq.pass.cpp
index cf89066a509..5c557fddc7f 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/eq.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/eq.pass.cpp
@@ -18,7 +18,7 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id0;
     std::thread::id id1;
@@ -28,4 +28,6 @@ int main()
     id1 = std::this_thread::get_id();
     assert(!(id1 == id0));
     assert( (id1 != id0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/lt.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/lt.pass.cpp
index 69ea217b506..8af73045a79 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/lt.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/lt.pass.cpp
@@ -20,7 +20,7 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id0;
     std::thread::id id1;
@@ -39,4 +39,6 @@ int main()
       assert( (id0 >  id2));
       assert( (id0 >= id2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/stream.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/stream.pass.cpp
index d07f26b1698..a1541c12e22 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/stream.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/stream.pass.cpp
@@ -20,9 +20,11 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id0 = std::this_thread::get_id();
     std::ostringstream os;
     os << id0;
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/thread_id.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/thread_id.pass.cpp
index 325c0bfebd4..80bcbf97c1d 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/thread_id.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/thread_id.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::thread::id id1;
     std::thread::id id2 = std::this_thread::get_id();
@@ -34,4 +34,6 @@ int main()
     ASSERT_NOEXCEPT(H()(id2));
     H h;
     assert(h(id1) != h(id2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/detach.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/detach.pass.cpp
index 8debe7770dd..bf72e3437a4 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/detach.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/detach.pass.cpp
@@ -61,7 +61,7 @@ bool G::op_run = false;
 
 void foo() {}
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -86,4 +86,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/get_id.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/get_id.pass.cpp
index 99cdec9134c..006bc1e65c4 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/get_id.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/get_id.pass.cpp
@@ -41,7 +41,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -54,4 +54,6 @@ int main()
         assert(t1.get_id() == std::thread::id());
         t0.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/join.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/join.pass.cpp
index c21de04ea34..b64a111c6be 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/join.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/join.pass.cpp
@@ -46,7 +46,7 @@ bool G::op_run = false;
 
 void foo() {}
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -73,4 +73,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/joinable.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/joinable.pass.cpp
index 3db473ab181..6f1308cbad0 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/joinable.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/joinable.pass.cpp
@@ -41,7 +41,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -50,4 +50,6 @@ int main()
         t0.join();
         assert(!t0.joinable());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/swap.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/swap.pass.cpp
index 66c810b1b7e..f43805d7fe6 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/swap.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/swap.pass.cpp
@@ -41,7 +41,7 @@ public:
 int G::n_alive = 0;
 bool G::op_run = false;
 
-int main()
+int main(int, char**)
 {
     {
         G g;
@@ -54,4 +54,6 @@ int main()
         assert(t1.get_id() == id0);
         t1.join();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.static/hardware_concurrency.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.static/hardware_concurrency.pass.cpp
index 3500f2c169a..5493f27a494 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.static/hardware_concurrency.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.static/hardware_concurrency.pass.cpp
@@ -17,7 +17,9 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::thread::hardware_concurrency() > 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.this/get_id.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.this/get_id.pass.cpp
index 864518dd8ff..1bf46cdb54f 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.this/get_id.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.this/get_id.pass.cpp
@@ -15,8 +15,10 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::thread::id id = std::this_thread::get_id();
     assert(id != std::thread::id());
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_for_tested_elsewhere.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_for_tested_elsewhere.pass.cpp
index 59791c84cdb..7c8552ea865 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_for_tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_for_tested_elsewhere.pass.cpp
@@ -16,6 +16,8 @@
 // is therefore non-standard. For this reason the test lives under the 'libcxx'
 // subdirectory.
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp
index 5fbaf9d8773..c73144db0c1 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp
@@ -18,7 +18,7 @@
 #include <cstdlib>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef Clock::time_point time_point;
@@ -30,4 +30,6 @@ int main()
     std::chrono::nanoseconds err = 5 * ms / 100;
     // The time slept is within 5% of 500ms
     assert(std::abs(ns.count()) < err.count());
+
+  return 0;
 }
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.this/yield.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.this/yield.pass.cpp
index 5c1caa0cbe0..6f772b5c286 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.this/yield.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.this/yield.pass.cpp
@@ -15,7 +15,9 @@
 #include <thread>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::this_thread::yield();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
index 6ea9a8ec8be..961eda3ac8f 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -113,4 +113,6 @@ int main()
              std::scoped_allocator_adaptor<A1<int>>,
              std::scoped_allocator_adaptor<A2<int>>>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp
index c1460603486..d3734cae10e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<double>> B;
@@ -64,4 +64,6 @@ int main()
         assert(a2 == a1);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp
index 99f0e38fc85..427e2995788 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<double>> B;
@@ -69,4 +69,6 @@ int main()
         assert(A3<int>::move_called == true);
         assert(a2 == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp
index 38878e234e9..69b767b909e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -64,4 +64,6 @@ int main()
         assert(A3<int>::move_called == false);
         assert(a2 == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp
index ac27f8b5465..fdf21cec3e0 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -53,4 +53,6 @@ int main()
         assert(A3<int>::move_called == false);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp
index 7b093826a85..6d644db85e8 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp
@@ -21,8 +21,10 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     std::scoped_allocator_adaptor<A1<int>> a;
     a.allocate(10);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp
index 057541dd099..05a1649e4a6 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -44,4 +44,6 @@ int main()
         assert(A1<int>::allocate_called == true);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp
index ffc59b80041..7cf3d410909 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp
@@ -21,8 +21,10 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     std::scoped_allocator_adaptor<A1<int>> a;
     a.allocate(10, (const void*)0); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp
index afe3e40d9f1..db9338d31b8 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -65,4 +65,6 @@ int main()
         assert(a.allocate(10, (const void*)20) == (int*)20);
         assert(A2<int>::allocate_called == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp
index 6e02326fa4b..97ae33d9157 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp
@@ -110,7 +110,7 @@ struct F
 
 bool F::constructed = false;
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -184,4 +184,6 @@ int main()
         assert(A3<F>::constructed);
         s->~S();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp
index 85fdd38f00d..7aa45f05add 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp
@@ -135,7 +135,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp
index 30fea45b021..d1a03bc05fc 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp
@@ -151,7 +151,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp
index c6e13bc1839..14f413bd867 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp
@@ -152,7 +152,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp
index 243b9e9979e..c26b4652cc4 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp
@@ -151,7 +151,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp
index acbe241e7c6..7a4b14956f0 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp
@@ -143,7 +143,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp
index 6a65d2ac6a0..e93f37f412e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp
@@ -125,8 +125,10 @@ void test_bullet_three() {
     POuter.reset();
 }
 
-int main() {
+int main(int, char**) {
     test_bullet_one();
     test_bullet_two();
     test_bullet_three();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp
index e5c17edaf12..425f00ad4f4 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -42,4 +42,6 @@ int main()
         assert((A1<int>::deallocate_called == std::pair<int*, std::size_t>((int*)10, 20)));
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp
index 02c7afe4a14..50c9d24f07d 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp
@@ -31,7 +31,7 @@ struct B
 
 bool B::constructed = false;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<B>> A;
@@ -65,4 +65,6 @@ int main()
         assert(A3<S>::destroy_called);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp
index ad0f2e2951f..7e73939f8ee 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -40,4 +40,6 @@ int main()
             std::scoped_allocator_adaptor<A2<int>, A3<int>>(A2<int>(6), A3<int>(8))));
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp
index 51a9f811786..de9cf4d0cad 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -38,4 +38,6 @@ int main()
         assert(a.max_size() == 200);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp
index ccea2b2c0e1..9a90d17c0c6 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -39,4 +39,6 @@ int main()
         A a(A1<int>(5), A2<int>(6), A3<int>(8));
         assert(a.outer_allocator() == A1<int>(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp
index ef42207574f..8253fee5518 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -50,4 +50,6 @@ int main()
         assert(a2.inner_allocator().inner_allocator().outer_allocator().id() == -1);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp
index 49f242ddf59..10475403d22 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp
@@ -109,7 +109,7 @@ void test_void_pointer()
 
 struct Foo { int x; };
 
-int main()
+int main(int, char**)
 {
     test_pointer<std::scoped_allocator_adaptor<std::allocator<char>>> ();
     test_pointer<std::scoped_allocator_adaptor<std::allocator<int>>> ();
@@ -118,7 +118,9 @@ int main()
     test_void_pointer<std::scoped_allocator_adaptor<std::allocator<char>>> ();
     test_void_pointer<std::scoped_allocator_adaptor<std::allocator<int>>> ();
     test_void_pointer<std::scoped_allocator_adaptor<std::allocator<Foo>>> ();
+
+  return 0;
 }
 #else
-int main() {}
+int main(int, char**) { return 0; }
 #endif
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp
index 05618904428..2aa7a989114 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::inner_allocator_type,
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::inner_allocator_type,
         std::scoped_allocator_adaptor<A2<int>, A3<int>>>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp
index a549366c9d9..628505f65cd 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp
@@ -21,7 +21,7 @@
 #include "allocators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     // sanity checks
     static_assert( (std::is_same<
@@ -68,4 +68,6 @@ int main()
               std::allocator_traits<A2<int>>::is_always_equal::value &&
               std::allocator_traits<A3<int>>::is_always_equal::value)
         ), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp
index 6f3605224bf..fea53af299e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::propagate_on_container_copy_assignment,
@@ -34,4 +34,6 @@ int main()
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::propagate_on_container_copy_assignment,
         std::true_type>::value), "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp
index 5c207c930c4..d04ea6f1a43 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::propagate_on_container_move_assignment,
@@ -34,4 +34,6 @@ int main()
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::propagate_on_container_move_assignment,
         std::true_type>::value), "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp
index 5b70dd8fb92..fcec67879fc 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::propagate_on_container_swap,
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::propagate_on_container_swap,
         std::true_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp
index 0f3813e1ab9..1f871876f13 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -68,4 +68,6 @@ int main()
         assert(A3<int>::move_called == false);
         assert(aN == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp
index 22987adefe7..aaf5c1d59ad 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -58,4 +58,6 @@ int main()
         assert(a2 != a1);
         assert(!(a2 == a1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp
index 0342f614c98..c17c6d38439 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -68,4 +68,6 @@ int main()
         assert(A3<int>::move_called == true);
         assert(aN == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp
index 00a007f06ea..7820e29eef2 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<
         A1<int>,
@@ -96,4 +96,6 @@ int main()
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A2<int>, A1<int>>::const_void_pointer,
         const void*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp
index 0a8c3f7814b..6cf1efb86b3 100644
--- a/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp
@@ -191,7 +191,7 @@ void test_copy_assign_throws()
 #endif
 }
 
-int main() {
+int main(int, char**) {
     test_copy_assign<small1, small2>();
     test_copy_assign<large1, large2>();
     test_copy_assign<small, large>();
@@ -201,4 +201,6 @@ int main() {
     test_copy_assign_self();
     test_copy_assign_throws<small_throws_on_copy>();
     test_copy_assign_throws<large_throws_on_copy>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp
index 4baadb2bbad..6e1b6d6a6f4 100644
--- a/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp
@@ -104,7 +104,7 @@ void test_move_assign_noexcept() {
       );
 }
 
-int main() {
+int main(int, char**) {
     test_move_assign_noexcept();
     test_move_assign<small1, small2>();
     test_move_assign<large1, large2>();
@@ -112,4 +112,6 @@ int main() {
     test_move_assign<large, small>();
     test_move_assign_empty<small>();
     test_move_assign_empty<large>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp
index 7ccec4b3f88..888a6a654b3 100644
--- a/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp
@@ -202,7 +202,7 @@ void test_sfinae_constraints() {
     }
 }
 
-int main() {
+int main(int, char**) {
     test_assign_value<small1, small2>();
     test_assign_value<large1, large2>();
     test_assign_value<small, large>();
@@ -213,4 +213,6 @@ int main() {
     test_assign_throws<large_throws_on_copy>();
     test_assign_throws<throws_on_move, /* Move = */ true>();
     test_sfinae_constraints();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp
index 6c4e9576d44..318d9ecabba 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp
@@ -98,10 +98,12 @@ void test_copy()
     assert(Type::count == 0);
 }
 
-int main() {
+int main(int, char**) {
     test_copy<small>();
     test_copy<large>();
     test_copy_empty();
     test_copy_throws<small_throws_on_copy>();
     test_copy_throws<large_throws_on_copy>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp
index 12692a17113..6cd7b8937d2 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp
@@ -20,7 +20,7 @@
 #include "any_helpers.h"
 #include "count_new.hpp"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     {
@@ -43,4 +43,6 @@ int main()
         any const a;
         assertEmpty(a);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp
index f696ac5a206..9684fcac7e2 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp
@@ -187,7 +187,7 @@ void test_constructor_explicit() {
     static_assert(std::is_constructible<std::any, IT, std::initializer_list<int>&, int>::value, "");
 }
 
-int main() {
+int main(int, char**) {
     test_in_place_type<small>();
     test_in_place_type<large>();
     test_in_place_type<small_throws_on_copy>();
@@ -198,4 +198,6 @@ int main() {
     test_in_place_type_decayed();
     test_ctor_sfinae();
     test_constructor_explicit();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp
index 265972a01e9..e75d56ef290 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp
@@ -95,7 +95,7 @@ void test_move() {
     assert(Type::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     // noexcept test
     {
@@ -108,4 +108,6 @@ int main()
     test_move<large>();
     test_move_empty();
     test_move_does_not_throw();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp
index c80a407ff06..ed588497514 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp
@@ -151,11 +151,13 @@ void test_sfinae_constraints() {
     }
 }
 
-int main() {
+int main(int, char**) {
     test_copy_move_value<small>();
     test_copy_move_value<large>();
     test_copy_value_throws<small_throws_on_copy>();
     test_copy_value_throws<large_throws_on_copy>();
     test_move_value_throws();
     test_sfinae_constraints();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
index 3ac003dd086..7cb5d491328 100644
--- a/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
@@ -275,7 +275,7 @@ void test_emplace_sfinae_constraints() {
     }
 }
 
-int main() {
+int main(int, char**) {
     test_emplace_type<small>();
     test_emplace_type<large>();
     test_emplace_type<small_throws_on_copy>();
@@ -288,4 +288,6 @@ int main() {
     test_emplace_throws<SmallThrows>();
     test_emplace_throws<LargeThrows>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp
index 352b25b8010..0a01e86252c 100644
--- a/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "any_helpers.h"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     using std::any_cast;
@@ -67,4 +67,6 @@ int main()
         assertEmpty<large>(a);
         assert(large::count == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp
index f1ff60d478b..f4f5ee4969c 100644
--- a/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp
@@ -127,7 +127,7 @@ void test_self_swap() {
     assert(large::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_noexcept();
     test_swap_empty<small>();
@@ -137,4 +137,6 @@ int main()
     test_swap<small, large>();
     test_swap<large, small>();
     test_self_swap();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp
index 9b747dca610..54b4153c974 100644
--- a/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "any_helpers.h"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     // noexcept test
@@ -60,4 +60,6 @@ int main()
         a = l;
         assert(a.has_value());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp
index 8d3b4081405..bb9089cd83e 100644
--- a/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "any_helpers.h"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     {
@@ -37,4 +37,6 @@ int main()
         any const a(l);
         assert(a.type() == typeid(large));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp b/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp
index b757f7b0bbe..3a275d51e4a 100644
--- a/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp
@@ -15,6 +15,8 @@
 #include <any>
 #include <type_traits>
 
-int main () {
+int main(int, char**) {
     static_assert(!std::is_literal_type<std::any>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp
index 8de9164c31f..9b9ec410958 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp
@@ -166,7 +166,7 @@ void test_cast_function_pointer() {
     assert(fn_ptr == test_fn);
 }
 
-int main() {
+int main(int, char**) {
     test_cast_is_noexcept();
     test_cast_return_type();
     test_cast_nullptr();
@@ -175,4 +175,6 @@ int main() {
     test_cast<large>();
     test_cast_non_copyable_type();
     test_cast_function_pointer();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp
index 810c482df78..fb69f0d39fb 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp
@@ -309,7 +309,7 @@ void test_cast_to_value() {
     assert(Type::count == 0);
 }
 
-int main() {
+int main(int, char**) {
     test_cast_is_not_noexcept();
     test_cast_return_type();
     test_cast_empty();
@@ -317,4 +317,6 @@ int main() {
     test_cast_to_reference<large>();
     test_cast_to_value<small>();
     test_cast_to_value<large>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp
index cd69a3d8508..396d994d22d 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp
@@ -61,9 +61,11 @@ void test_rvalue_any_cast_request_lvalue()
     any_cast<int&>(42);
 }
 
-int main()
+int main(int, char**)
 {
     test_const_lvalue_cast_request_non_const_lvalue();
     test_lvalue_any_cast_request_rvalue();
     test_rvalue_any_cast_request_lvalue();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp
index c0c6e03fdcf..8669de4fddb 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp
@@ -24,7 +24,7 @@ struct TestType2 {};
 // is triggered by these tests.
 // expected-error@const_correctness.fail.cpp:* 0+ {{call to unavailable function 'any_cast': introduced in macOS 10.14}}
 
-int main()
+int main(int, char**)
 {
     using std::any;
     using std::any_cast;
@@ -46,4 +46,6 @@ int main()
     // expected-error@any:* {{cannot cast from lvalue of type 'const TestType2' to rvalue reference type 'TestType2 &&'; types are not compatible}}
     // expected-error-re@any:* {{static_assert failed{{.*}} "ValueType is required to be a const lvalue reference or a CopyConstructible type"}}
     any_cast<TestType2 &&>(static_cast<any const&&>(a)); // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp
index c90df2ebd37..97f1d9795bc 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp
@@ -43,7 +43,7 @@ struct no_move {
 // is triggered by these tests.
 // expected-error@not_copy_constructible.fail.cpp:* 0+ {{call to unavailable function 'any_cast': introduced in macOS 10.14}}
 
-int main() {
+int main(int, char**) {
     any a;
     // expected-error-re@any:* {{static_assert failed{{.*}} "ValueType is required to be an lvalue reference or a CopyConstructible type"}}
     // expected-error@any:* {{static_cast from 'no_copy' to 'no_copy' uses deleted function}}
@@ -58,4 +58,6 @@ int main() {
     // expected-error-re@any:* {{static_assert failed{{.*}} "ValueType is required to be an rvalue reference or a CopyConstructible type"}}
     // expected-error@any:* {{static_cast from 'typename remove_reference<no_move &>::type' (aka 'no_move') to 'no_move' uses deleted function}}
     any_cast<no_move>(static_cast<any &&>(a));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp
index 19453582479..1ce06e289a9 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp
@@ -21,7 +21,7 @@
 using std::any;
 using std::any_cast;
 
-int main()
+int main(int, char**)
 {
     any a(1);
 
@@ -50,4 +50,6 @@ int main()
 
     // expected-error-re@any:* 1 {{static_assert failed{{.*}} "_ValueType may not be a reference."}}
     any_cast<int const &&>(&a2); // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp
index e185f239f69..1e9708545ff 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp
@@ -131,7 +131,7 @@ void test_make_any_throws()
 
 #endif
 
-int main() {
+int main(int, char**) {
     test_make_any_type<small>();
     test_make_any_type<large>();
     test_make_any_type<small_throws_on_copy>();
@@ -144,4 +144,6 @@ int main() {
     test_make_any_throws<LargeThrows>();
 
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp
index 3e5a91d0d23..cff34964a84 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp
@@ -28,7 +28,7 @@
 using std::any;
 using std::any_cast;
 
-int main()
+int main(int, char**)
 {
 
     { // test noexcept
@@ -44,4 +44,6 @@ int main()
         assert(any_cast<int>(a1) == 2);
         assert(any_cast<int>(a2) == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp
index 35ddfa32e88..2e744cc8187 100644
--- a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp
@@ -18,7 +18,7 @@
 
 #include <charconv>
 
-int main()
+int main(int, char**)
 {
     using std::from_chars;
     char buf[] = "01001";
@@ -26,4 +26,6 @@ int main()
 
     from_chars(buf, buf + sizeof(buf), lv);      // expected-error {{call to deleted function}}
     from_chars(buf, buf + sizeof(buf), lv, 16);  // expected-error {{call to deleted function}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp
index 9f05250d356..d750cb4a89c 100644
--- a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp
@@ -183,8 +183,10 @@ struct test_signed : roundtrip_test_base<T>
     }
 };
 
-int main()
+int main(int, char**)
 {
     run<test_basics>(integrals);
     run<test_signed>(all_signed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp
index 36c7d3ccadb..5c947d122f4 100644
--- a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp
@@ -18,7 +18,7 @@
 
 #include <charconv>
 
-int main()
+int main(int, char**)
 {
     using std::to_chars;
     char buf[10];
@@ -26,4 +26,6 @@ int main()
 
     to_chars(buf, buf + sizeof(buf), false);   // expected-error {{call to deleted function}}
     to_chars(buf, buf + sizeof(buf), lv, 16);  // expected-error {{call to deleted function}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp
index 18ddf203b3e..c034151de8a 100644
--- a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp
@@ -81,8 +81,10 @@ struct test_signed : to_chars_test_base<T>
     }
 };
 
-int main()
+int main(int, char**)
 {
     run<test_basics>(integrals);
     run<test_signed>(all_signed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
index c191b191bcd..1dbbd8533c7 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::divides<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::divides<> () (3.0, 2);
     static_assert ( bar == 1.5, "" ); // exact in binary
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp
index 54ab577ea43..186695f7b93 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::minus<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::minus<> () (3.0, 2);
     static_assert ( bar == 1.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp
index f426c57cfee..3679a2d3251 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::modulus<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr int bar = std::modulus<> () (3L, 2);
     static_assert ( bar == 1, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp
index 5ef4791b59e..a09e59c784c 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::multiplies<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::multiplies<> () (3.0, 2);
     static_assert ( bar == 6.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
index d7346c769f7..553bf83e2d4 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::negate<int> F;
     const F f = F();
@@ -36,4 +36,6 @@ int main()
     constexpr double bar = std::negate<> () (3.0);
     static_assert ( bar == -3.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp
index 6bca266e078..b2614f4304d 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::plus<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::plus<> () (3.0, 2);
     static_assert ( bar == 5.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp
index ca57c223a2a..154a0f8877a 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main ()
+int main(int, char**)
 {
     static_assert ( !is_transparent<std::plus<int>>::value, "" );
     static_assert ( !is_transparent<std::plus<std::string>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
index 4c025d1415a..931778f54d9 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
@@ -28,7 +28,9 @@ struct Fun
   }
 };
 
-int main()
+int main(int, char**)
 {
     std::bind(Fun{}, std::placeholders::_1, 42)("hello");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp
index fc089e16528..7010b33f331 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp
@@ -115,7 +115,7 @@ void do_test_r(Fn* func) {
     }
 }
 
-int main()
+int main(int, char**)
 {
     do_test<int>(return_value);
     do_test<int&>(return_lvalue);
@@ -129,4 +129,6 @@ int main()
     do_test_r<long>(return_rvalue);
     do_test_r<long>(return_const_rvalue);
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp
index ccc6c27e716..8beeb3321d5 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp
@@ -26,11 +26,13 @@ float _pow(float a, float b)
     return std::pow(a, b);
 }
 
-int main()
+int main(int, char**)
 {
     std::function<float(float, float)> fnc = _pow;
     auto task = std::bind(fnc, 2.f, 4.f);
     auto task2(task);
     assert(task() == 16);
     assert(task2() == 16);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
index b386b99a90f..b87918da110 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
@@ -38,7 +38,7 @@ struct BadUnaryFunction
     }
 };
 
-int main()
+int main(int, char**)
 {
     // Check that BadUnaryFunction::operator()(S const &) is not
     // instantiated when checking if BadUnaryFunction is a nested bind
@@ -47,4 +47,6 @@ int main()
     b(0);
     auto b2 = std::bind<long>(DummyUnaryFunction(), BadUnaryFunction());
     b2(0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp
index 8d6bc70e79a..a77e1895d6f 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp
@@ -40,7 +40,7 @@ struct A_int_0
     int operator()() const {return 5;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::bind(f), 1);
     test(std::bind(&f), 1);
@@ -51,4 +51,6 @@ int main()
     test(std::bind<int>(&f), 1);
     test(std::bind<int>(A_int_0()), 4);
     test_const(std::bind<int>(A_int_0()), 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp
index 92f65af2c91..9b81d330132 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp
@@ -280,10 +280,12 @@ test3()
     assert(b);
 }
 
-int main()
+int main(int, char**)
 {
     test_void_1();
     test_int_1();
     test_void_2();
     test3();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp
index b7facb38ac6..10d2ce017f8 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp
@@ -258,10 +258,12 @@ void test_nested()
     assert(std::bind(f_nested, std::bind(g_nested, _1))(3) == 31);
 }
 
-int main()
+int main(int, char**)
 {
     test_void_1();
     test_int_1();
     test_void_2();
     test_nested();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp
index cc982d1b80f..2c8e56f034e 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp
@@ -54,7 +54,7 @@ struct A_int_0
     int operator()() const {count += 2; return 5;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::bind(f));
     test(std::bind(&f));
@@ -70,4 +70,6 @@ int main()
     test(std::bind<void>(&g));
     test(std::bind<void>(A_int_0()));
     test_const(std::bind<void>(A_int_0()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
index c4d82948e37..0d5be341353 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
@@ -41,11 +41,13 @@ struct plus_one
   }
 };
 
-int main()
+int main(int, char**)
 {
     using std::placeholders::_1;
 
     auto g = std::bind(power(), 2, _1);
     assert(g(5) == 32);
     assert(std::bind(plus_one(), g)(5) == 33);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp
index cf065e4e382..8314dbe1e8e 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp
@@ -27,11 +27,13 @@ test(const T&)
 
 struct C {};
 
-int main()
+int main(int, char**)
 {
     test<true>(std::bind(C()));
     test<true>(std::bind(C(), std::placeholders::_2));
     test<true>(std::bind<int>(C()));
     test<false>(1);
     test<false>(std::placeholders::_2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp
index da7880fb25f..c1af159b293 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp
@@ -24,7 +24,7 @@ void test() {
 
 struct C {};
 
-int main() {
+int main(int, char**) {
     test<int>();
     test<void>();
     test<C>();
@@ -35,4 +35,6 @@ int main() {
     test<int(*)()>();
     test<int (C::*)()>();
     test<decltype(std::placeholders::_2)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp
index ecaa45bba28..d2ccf1fafdc 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp
@@ -25,7 +25,7 @@ test(const T&)
 
 struct C {};
 
-int main()
+int main(int, char**)
 {
     test<1>(std::placeholders::_1);
     test<2>(std::placeholders::_2);
@@ -41,4 +41,6 @@ int main()
     test<0>(5.5);
     test<0>('a');
     test<0>(C());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp
index 8e4ec60ef13..b71aae818a0 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp
@@ -80,7 +80,7 @@ void use_placeholders_to_prevent_unused_warning() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     use_placeholders_to_prevent_unused_warning();
     test(std::placeholders::_1);
@@ -93,4 +93,6 @@ int main()
     test(std::placeholders::_8);
     test(std::placeholders::_9);
     test(std::placeholders::_10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp
index 664e3f25dd6..aa532462145 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::bit_and<int> F;
     const F f = F();
@@ -57,4 +57,6 @@ int main()
     constexpr int bar = std::bit_and<> () (0x58D3L, 0xEA95);
     static_assert ( bar == 0x4891, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
index e18139bc607..8bfa48f3e70 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::bit_not<int> F;
     const F f = F();
@@ -42,4 +42,6 @@ int main()
 
     constexpr int bar = std::bit_not<> () (0xEA95) & 0xFFFF;
     static_assert ( bar == 0x156A, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp
index 19bd1a731c8..8abcd63afaa 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::bit_or<int> F;
     const F f = F();
@@ -57,4 +57,6 @@ int main()
     constexpr int bar = std::bit_or<> () (0x58D3L, 0xEA95);
     static_assert ( bar == 0xFAD7, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp
index 757417a2cb5..070bd4c5f7b 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::bit_xor<int> F;
@@ -61,4 +61,6 @@ int main()
     static_assert ( bar == 0xB246, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp
index c360a51b4e9..5ad0f233f19 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main () {
+int main(int, char**) {
     static_assert ( !is_transparent<std::bit_and<int>>::value, "" );
     static_assert ( !is_transparent<std::bit_and<std::string>>::value, "" );
     static_assert (  is_transparent<std::bit_and<void>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp
index 7632dc58061..a0c41432ec4 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp
@@ -42,6 +42,8 @@ static_assert(test_constexpr_context<int>(), "");
 static_assert(test_constexpr_context<void>(), "");
 
 
-int main() {
+int main(int, char**) {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp
index 7ec8f66328d..beed574f89e 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::equal_to<int> F;
     const F f = F();
@@ -39,4 +39,6 @@ int main()
     constexpr bool bar = std::equal_to<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp
index 12111ef28e3..35c05757c8c 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::greater<int> F;
     const F f = F();
@@ -49,4 +49,6 @@ int main()
     constexpr bool bar = std::greater<> () (36.0, 36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp
index 1ac67eadc38..9a6d36c4176 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::greater_equal<int> F;
     const F f = F();
@@ -49,4 +49,6 @@ int main()
     constexpr bool bar = std::greater_equal<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp
index abfe09ad58d..31a2f975b18 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::less<int> F;
     const F f = F();
@@ -48,4 +48,6 @@ int main()
     constexpr bool bar = std::less<> () (36.0, 36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp
index 2e733042409..31cbed17172 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::less_equal<int> F;
     const F f = F();
@@ -49,4 +49,6 @@ int main()
     constexpr bool bar = std::less_equal<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp
index fd329157058..0e405de1be9 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::not_equal_to<int> F;
     const F f = F();
@@ -41,4 +41,6 @@ int main()
     constexpr bool bar = std::not_equal_to<> () (36.0, 36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp
index f3896770ec0..4be81925b7f 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main ()
+int main(int, char**)
 {
     static_assert ( !is_transparent<std::less<int>>::value, "" );
     static_assert ( !is_transparent<std::less<std::string>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp b/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp
index b0a41447e05..57350f16c40 100644
--- a/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp
@@ -340,9 +340,11 @@ void noexcept_test() {
     }
 }
 
-int main() {
+int main(int, char**) {
     bullet_one_two_tests();
     bullet_three_four_tests();
     bullet_five_tests();
     noexcept_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp b/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp
index f7f63a0bd8b..b0404659d78 100644
--- a/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp
@@ -31,8 +31,10 @@
 
 int foo(int) { return 42; }
 
-int main() {
+int main(int, char**) {
 #if defined(__cpp_lib_invoke)
   assert(std::invoke(foo, 101) == 42);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp
index 483f7a327c3..130644fbd29 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp
@@ -35,7 +35,9 @@ test(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test(std::mem_fn(&A::data_));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp
index 75211ba21e0..52581881a5b 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp
@@ -36,7 +36,9 @@ test(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test(std::mem_fn(&A::data_));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp
index a04e49efa20..a271c067008 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp
@@ -65,7 +65,7 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
@@ -73,4 +73,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((noexcept(std::mem_fn(&A::test0))), ""); // LWG#2489
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp
index 9ea6531a2ec..dc93196cdc3 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp
@@ -69,9 +69,11 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
     test2(std::mem_fn(&A::test2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
index 9258c0a03f4..594e1de8ad6 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
@@ -69,9 +69,11 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
     test2(std::mem_fn(&A::test2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
index c22baecd9b8..04439387dfe 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
@@ -69,9 +69,11 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
     test2(std::mem_fn(&A::test2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp b/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp
index c3adbf7ffc5..a1c77841247 100644
--- a/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp
@@ -602,7 +602,7 @@ void test_lwg2767() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     constructor_tests();
     return_type_tests();
@@ -612,4 +612,6 @@ int main()
     call_operator_forwarding_test();
     call_operator_noexcept_test();
     test_lwg2767();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp
index 2bb9cb58371..00b7d53be3a 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp
@@ -12,4 +12,6 @@
 // since they require calling the implementation specific "__invoke" and
 // "__invoke_constexpr" functions.
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp
index 76ba44fc994..79a4855ea02 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp
@@ -15,10 +15,12 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::binary_function<int, short, bool> bf;
     static_assert((std::is_same<bf::first_argument_type, int>::value), "");
     static_assert((std::is_same<bf::second_argument_type, short>::value), "");
     static_assert((std::is_same<bf::result_type, bool>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp
index 0d178b0dc6d..f68b4b37c73 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp
@@ -15,9 +15,11 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::unary_function<int, bool> uf;
     static_assert((std::is_same<uf::argument_type, int>::value), "");
     static_assert((std::is_same<uf::result_type, bool>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp
index 3293a3215ed..55cde8fe777 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp
@@ -122,7 +122,9 @@ test2()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp
index d0ce11b08bb..106b0d37f61 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp
@@ -118,7 +118,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp
index 59178deb613..be4db4e5a54 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp
@@ -136,7 +136,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp
index 7f3e837a70e..3656caa8749 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp
@@ -127,7 +127,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp
index 04adb178bf1..0b345deedc1 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp
@@ -122,7 +122,9 @@ test2()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp
index dca69117583..4106c5d6ae7 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp
@@ -117,7 +117,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp
index 6a5c215a7fd..757bcc75792 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp
@@ -130,7 +130,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp
index 27c3d0c82c2..3a20b88512f 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp
@@ -124,7 +124,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp
index 098b8ac113d..eaf5eeb8273 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp
@@ -82,7 +82,7 @@ test()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -92,4 +92,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
index 4b0f016d712..773336f6626 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
@@ -89,7 +89,7 @@ test()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -99,4 +99,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp
index 2ec1d53c56e..eb223b88e49 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp
@@ -19,7 +19,9 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_function_call>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp
index 6b6ee8a64a7..385919227e0 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp
@@ -13,7 +13,9 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::bad_function_call ex;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp
index 50fb4f19d5b..2a34eff92e2 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp
@@ -18,7 +18,9 @@
 
 struct S : public std::function<void()> { using function::function; };
 
-int main() {
+int main(int, char**) {
    S f1( [](){} );
    S f2(std::allocator_arg, std::allocator<int>{}, f1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp
index 8c50c284b42..70f68d2f49b 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp
@@ -20,10 +20,12 @@
 using Fn = std::function<void()>;
 struct S : public std::function<void()> { using function::function; };
 
-int main() {
+int main(int, char**) {
     S s( [](){} );
     S f1( s );
 #if TEST_STD_VER <= 14
     S f2(std::allocator_arg, std::allocator<int>{}, s);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp
index b6dbcab5301..ec25bdf7802 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp
@@ -57,7 +57,7 @@ int A::count = 0;
 int g(int) {return 0;}
 int h(int) {return 1;}
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -132,4 +132,6 @@ int main()
     }
     assert(A::count == 0);
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp
index 1b55baa02e1..ab5eef37270 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp
@@ -17,7 +17,7 @@
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f;
@@ -25,4 +25,6 @@ int main()
     f = g;
     assert(f);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp
index c32baebb51d..fe5d24806b7 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp
@@ -60,7 +60,7 @@ struct LValueCallable {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -111,4 +111,6 @@ int main()
         static_assert(!std::is_constructible<Fn, RValueCallable>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp
index abff663cb72..f70a2087cc2 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp
@@ -63,7 +63,7 @@ struct LValueCallable {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -115,4 +115,6 @@ int main()
         static_assert(!std::is_assignable<Fn&, RValueCallable>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp
index 1598486661c..21c2f216efe 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp
@@ -58,6 +58,8 @@ void test_pr34298()
   }
 }
 
-int main() {
+int main(int, char**) {
   test_pr34298();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp
index 89b7876235e..ebea3d0aa95 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp
@@ -239,8 +239,10 @@ void test_md() {
     test_imp<int MemData::*, int(MemData&)>();
 }
 
-int main() {
+int main(int, char**) {
     test_func();
     test_mf();
     test_md();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp
index acbeb9f9c98..50a11fb8198 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp
@@ -18,7 +18,9 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(std::allocator_arg, std::allocator<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp
index b048109e54b..3b37ce6ffdc 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp
@@ -20,10 +20,12 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f(std::allocator_arg, bare_allocator<int>());
     assert(!f);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp
index bddc9278719..c31c0a21f32 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp
@@ -22,7 +22,9 @@
 
 void foo(int) {}
 
-int main()
+int main(int, char**)
 {
     std::function<void(int)> f(std::allocator_arg, std::allocator<int>(), foo);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp
index 4d49434f317..6fa0d6faeaf 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp
@@ -106,7 +106,7 @@ void test_for_alloc(Alloc& alloc) {
     test_MemFunClass<int(MemFunClass::*)(int, int) const, int(MemFunClass&, int, int)>(alloc);
 }
 
-int main()
+int main(int, char**)
 {
     {
         bare_allocator<DummyClass> bare_alloc;
@@ -126,4 +126,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp
index b6703c0b7b9..621588f8156 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp
@@ -21,9 +21,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::function<void(int)> F;
     F f1;
     F f2(std::allocator_arg, std::allocator<int>(), f1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp
index 39050e6f153..583ca162ebf 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp
@@ -111,7 +111,7 @@ void test_for_alloc(Alloc& alloc)
     test_MemFunClass<int(MemFunClass::*)(int, int) const, int(MemFunClass&, int, int)>(alloc);
 }
 
-int main()
+int main(int, char**)
 {
   {
     bare_allocator<DummyClass> alloc;
@@ -121,4 +121,6 @@ int main()
     non_default_test_allocator<DummyClass> alloc(42);
     test_for_alloc(alloc);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp
index 32d19ebf704..52bc528fe59 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp
@@ -20,7 +20,9 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(std::allocator_arg, std::allocator<int>(), nullptr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp
index 6378a6cd9d3..653057f6ec9 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp
@@ -20,8 +20,10 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(std::allocator_arg, bare_allocator<int>(), nullptr);
     assert(!f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp
index 558b7814ced..643cad8f074 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp
@@ -50,10 +50,12 @@ int A::count = 0;
 
 int g(int) { return 0; }
 
-int main()
+int main(int, char**)
 {
     {
         std::function<int(int)> f = A();
         std::function<int(int)> f2(std::allocator_arg, std::allocator<A>(), std::move(f));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp
index 8f379e30305..064046d0b2d 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp
@@ -54,7 +54,7 @@ int A::count = 0;
 
 int g(int) { return 0; }
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -105,4 +105,6 @@ int main()
         assert(f2.target<Ptr>());
         assert(f.target<Ptr>()); // f is unchanged because the target is small
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp
index df2a43aba9d..d7b11ae1bfd 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp
@@ -48,7 +48,7 @@ int g(int) { return 0; }
 int g2(int, int) { return 2; }
 int g3(int, int, int) { return 3; }
 
-int main() {
+int main(int, char**) {
   assert(globalMemCounter.checkOutstandingNewEq(0));
   {
     std::function<int(int)> f = A();
@@ -134,4 +134,6 @@ int main() {
     assert(f.target<int (*)(int)>() == 0);
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp
index 9f03ee7a1f9..dbbde5ce473 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp
@@ -50,7 +50,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -161,4 +161,6 @@ int main()
         LIBCPP_ASSERT(f.target<Ptr>()); // f is unchanged because the target is small
     }
 #endif  // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp
index 06ea4e058d0..46c14ce368b 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp
@@ -15,8 +15,10 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f;
     assert(!f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp
index 026cfc2d484..e15fbbaae54 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp
@@ -33,7 +33,7 @@ struct A
 std::function<void()> A::global;
 bool A::cancel = false;
 
-int main()
+int main(int, char**)
 {
   A::global = A();
   assert(A::global.target<A>());
@@ -42,4 +42,6 @@ int main()
   A::cancel = true;
   A::global = std::function<void()>(nullptr);
   assert(!A::global.target<A>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp
index b685d53bfa0..d58e191c470 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp
@@ -15,8 +15,10 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(nullptr);
     assert(!f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp
index 7a8d3e380e2..ff81080ffda 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp
@@ -46,7 +46,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -68,4 +68,6 @@ int main()
     assert(globalMemCounter.checkOutstandingNewEq(0));
     assert(f.target<int(*)(int)>() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp
index c4006a7c9fd..def86085ddb 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp
@@ -33,7 +33,7 @@ struct A
 std::function<void()> A::global;
 bool A::cancel = false;
 
-int main()
+int main(int, char**)
 {
   A::global = A();
   assert(A::global.target<A>());
@@ -42,4 +42,6 @@ int main()
   A::cancel = true;
   A::global = nullptr;
   assert(!A::global.target<A>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp
index 5f91e5c87d9..0f8e051d406 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp
@@ -39,7 +39,9 @@ test_int_1()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_int_1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp
index 7775cad6773..fb67a3abf4a 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp
@@ -401,7 +401,7 @@ void test_int_2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_void_0();
     test_int_0();
@@ -409,4 +409,6 @@ int main()
     test_int_1();
     test_void_2();
     test_int_2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp
index 5a6f503a284..8ddd1cd2b18 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp
@@ -48,7 +48,7 @@ public:
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     {
@@ -60,4 +60,6 @@ int main()
     }
     assert(A::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp
index a75aee33048..93997a0b55f 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp
@@ -57,7 +57,7 @@ int h(int) { return 1; }
 int g2(int, int) { return 2; }
 int g3(int, int, int) { return 3; }
 
-int main() {
+int main(int, char**) {
   assert(globalMemCounter.checkOutstandingNewEq(0));
   {
     std::function<int(int)> f1 = A(1);
@@ -189,4 +189,6 @@ int main() {
   }
   assert(globalMemCounter.checkOutstandingNewEq(0));
   assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp
index c68a1ca8262..698a461c8f0 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp
@@ -27,7 +27,7 @@
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f;
@@ -37,4 +37,6 @@ int main()
     assert(f != nullptr);
     assert(nullptr != f);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp
index 7b59b56d092..d5031ba06e7 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp
@@ -55,7 +55,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f = A();
@@ -89,4 +89,6 @@ int main()
     assert(f.target<int>() == nullptr);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp
index 52d07a45a50..d9c8fc48d75 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp
@@ -47,7 +47,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f = A();
@@ -57,4 +57,6 @@ int main()
     std::function<int(int)> f;
     assert(f.target_type() == typeid(void));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp
index 496dee8ae75..8083ad83ac0 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp
@@ -98,10 +98,12 @@ void test_other_function ()
     static_assert((!has_second_argument_type<F>::value), "" );
 }
 
-int main()
+int main(int, char**)
 {
     test_nullary_function<std::function<int()>, int>();
     test_unary_function  <std::function<double(int)>, double, int>();
     test_binary_function <std::function<double(int, char)>, double, int, char>();
     test_other_function  <std::function<double(int, char, double)>, double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp
index 1b0a1c63f16..29767a58c48 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_and<int> F;
     const F f = F();
@@ -48,4 +48,6 @@ int main()
     constexpr bool bar = std::logical_and<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
index 2c0c9f3bc90..e93fd06fdd5 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_not<int> F;
     const F f = F();
@@ -38,4 +38,6 @@ int main()
     constexpr bool bar = std::logical_not<> () (36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp
index 497a9d981f1..abe536572ea 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_or<int> F;
     const F f = F();
@@ -47,4 +47,6 @@ int main()
     constexpr bool bar = std::logical_or<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp
index 3aa24c44330..eb590b31a01 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main ()
+int main(int, char**)
 {
     static_assert ( !is_transparent<std::logical_and<int>>::value, "" );
     static_assert ( !is_transparent<std::logical_and<std::string>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp
index ca8b76711cf..713afc66562 100644
--- a/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp
@@ -28,7 +28,9 @@ struct Predicate {
     bool operator()(first_argument_type, second_argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::binary_negate<Predicate> f((Predicate())); // expected-error{{'binary_negate<Predicate>' is deprecated}}
     (void)f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp
index 1e7edcb3242..41541c10ff1 100644
--- a/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::binary_negate<std::logical_and<int> > F;
     const F f = F(std::logical_and<int>());
@@ -25,4 +25,6 @@ int main()
     assert( f(36, 0));
     assert( f(0, 36));
     assert( f(0, 0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp
index 9fbe6db66f9..407cbd4fc26 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp
@@ -27,6 +27,8 @@ struct Predicate {
     bool operator()(argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::not1(Predicate()); // expected-error{{'not1<Predicate>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp
index 33268222b5d..07c160a97ab 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp
@@ -13,9 +13,11 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_not<int> F;
     assert(std::not1(F())(36));
     assert(!std::not1(F())(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp
index 032ce3429dc..24178e0a05d 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp
@@ -28,6 +28,8 @@ struct Predicate {
     bool operator()(first_argument_type, second_argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::not2(Predicate()); // expected-error{{'not2<Predicate>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp
index 208d33b4a3e..d9f3c95fd89 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp
@@ -13,11 +13,13 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_and<int> F;
     assert(!std::not2(F())(36, 36));
     assert( std::not2(F())(36, 0));
     assert( std::not2(F())(0, 36));
     assert( std::not2(F())(0, 0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp
index 99cdf136d64..15a0a277826 100644
--- a/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp
@@ -27,7 +27,9 @@ struct Predicate {
     bool operator()(argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::unary_negate<Predicate> f((Predicate())); // expected-error{{'unary_negate<Predicate>' is deprecated}}
     (void)f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
index ec00c3e32a2..54fd54f3969 100644
--- a/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::unary_negate<std::logical_not<int> > F;
     const F f = F(std::logical_not<int>());
@@ -22,4 +22,6 @@ int main()
     static_assert((std::is_same<F::result_type, bool>::value), "" );
     assert(f(36));
     assert(!f(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp
index 5e67db520fb..c15989f003e 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp
@@ -30,7 +30,7 @@ test(T& t)
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -41,4 +41,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp
index 16ce961126c..3ef0cdda869 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp
@@ -42,7 +42,7 @@ test_function()
     assert(&r2.get() == &f);
 }
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -53,4 +53,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp
index 64726b53ef8..355047d98ce 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp
@@ -30,7 +30,7 @@ test(T& t)
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -41,4 +41,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
index f7a6670b431..f02a9974d7d 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
@@ -17,7 +17,9 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::reference_wrapper<const int> r(3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp
index 2cbb1a010f1..a43d0fd2510 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp
@@ -29,7 +29,7 @@ test(T& t)
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -40,4 +40,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp
index b16a4b476c3..d4cb421f53e 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp
@@ -15,9 +15,11 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::reference_wrapper<const int> r = std::cref(i);
     assert(&r.get() == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp
index 3023f8da2a3..093b7e230fd 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp
@@ -15,10 +15,12 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const int i = 0;
     std::reference_wrapper<const int> r1 = std::cref(i);
     std::reference_wrapper<const int> r2 = std::cref(r1);
     assert(&r2.get() == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
index 9e283d1bfaf..c07028d21dd 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
@@ -22,7 +22,9 @@ struct A {};
 
 const A source() {return A();}
 
-int main()
+int main(int, char**)
 {
     std::reference_wrapper<const A> r = std::ref(source());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp
index a8af5aa4cfe..f64d8ad8cae 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp
@@ -15,9 +15,11 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::reference_wrapper<int> r = std::ref(i);
     assert(&r.get() == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp
index fee5009a73b..4fdaf992c64 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp
@@ -22,7 +22,7 @@ bool is5 ( int i ) { return i == 5; }
 template <typename T>
 bool call_pred ( T pred ) { return pred(5); }
 
-int main()
+int main(int, char**)
 {
     {
     int i = 0;
@@ -39,4 +39,6 @@ int main()
     assert(call_pred(std::ref(cp)));
     assert(cp.count() == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp
index 6302c51b8ad..d54d5184c65 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp
@@ -45,7 +45,9 @@ test_int_1()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_int_1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp
index 425bc6df0c8..fd31041330d 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp
@@ -319,10 +319,12 @@ testint_2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_void_1();
     test_int_1();
     test_void_2();
     testint_2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp
index 37d7cfca9de..67cf51f3359 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp
@@ -69,7 +69,9 @@ struct A_void_1
     }
 };
 
-int main()
+int main(int, char**)
 {
     test_int_0();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp
index 735bfd890dd..18e65531333 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp
@@ -61,7 +61,9 @@ test_void_0()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_void_0();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp
index ef46e15d0a0..d17ab8100ef 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp
@@ -17,7 +17,7 @@
 
 class C {};
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::reference_wrapper<C>::type,
                                                        C>::value), "");
@@ -33,4 +33,6 @@ int main()
                                                        int*(C::*)(double*)>::value), "");
     static_assert((std::is_same<std::reference_wrapper<int (C::*)(double*) const volatile>::type,
                                                        int (C::*)(double*) const volatile>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp
index 14a06a9c316..17eef26f07a 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp
@@ -52,7 +52,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<double>();
@@ -60,4 +60,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<MoveOnly>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
index 9aaa2827997..1987898393c 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
@@ -28,7 +28,7 @@ void check() {
 
 struct T { };
 
-int main() {
+int main(int, char**) {
   check<T,             T>();
   check<T&,            T>();
   check<T const,       T>();
@@ -54,4 +54,6 @@ int main() {
   check<std::reference_wrapper<T[3]>&,     T (&)[3]>();
   check<std::reference_wrapper<T ()>,      T (&)()>();
   check<std::reference_wrapper<T ()>&,     T (&)()>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
index f6d48a51e8b..209d5e2a0bc 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
@@ -39,7 +39,7 @@ void check() {
 
 struct T { };
 
-int main() {
+int main(int, char**) {
   check<T>();
   check<int>();
   check<float>();
@@ -47,4 +47,6 @@ int main() {
   check<T*>();
   check<int*>();
   check<float*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp
index 50cda116932..5a6a41fdbe0 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp
@@ -68,7 +68,7 @@ public:
     static const bool value = sizeof(test<T>(0)) == 1;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::reference_wrapper<functor1>::result_type,
                                 char>::value), "");
@@ -93,4 +93,6 @@ int main()
     static_assert(has_result_type<std::reference_wrapper<functor3> >::value, "");
     static_assert(!has_result_type<std::reference_wrapper<functor4> >::value, "");
     static_assert(!has_result_type<std::reference_wrapper<C> >::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp
index 90ab8e1bb79..8f6c3e14e2c 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp
index b824b51ea79..2e36b4c5531 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp
@@ -16,8 +16,10 @@
 
 struct X {};
 
-int main()
+int main(int, char**)
 {
     X x;
     size_t h = std::hash<X>{} ( x );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
index 96c667febcb..e172bc2f346 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
@@ -49,7 +49,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<Cardinals>();
 
@@ -59,4 +59,6 @@ int main()
     test<EightBitColors>();
 
     test<Fruits>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
index 1ab1643413a..31b1b2d07e4 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
@@ -64,9 +64,11 @@ test()
     assert(pinf != ninf);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
index 761c76dc141..dbd44a88207 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
@@ -46,7 +46,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>();
     test<char>();
@@ -108,4 +108,6 @@ int main()
     test<__int128_t>();
     test<__uint128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp
index 6efcebc4ebe..c47f8fa76a4 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp
@@ -22,7 +22,7 @@
 
 struct X {};
 
-int main()
+int main(int, char**)
 {
     using H = std::hash<X>;
     static_assert(!std::is_default_constructible<H>::value, "");
@@ -34,4 +34,6 @@ int main()
     static_assert(!std::is_invocable<H, X&>::value, "");
     static_assert(!std::is_invocable<H, X const&>::value, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp
index cbf2c736eab..17dfdce2d4a 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp
@@ -52,8 +52,10 @@ void test_nullptr()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int*>();
     test_nullptr();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp
index 8da459ff81d..90b09132d9e 100644
--- a/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp
@@ -21,7 +21,7 @@ auto extract ( const AtContainer &t, const std::integer_sequence<T, I...> )
 -> decltype ( std::make_tuple ( std::get<I>(t)... ))
 {     return  std::make_tuple ( std::get<I>(t)... ); }
 
-int main()
+int main(int, char**)
 {
 //  Make a couple of sequences
     using int3    = std::make_integer_sequence<int, 3>;     // generates int:    0,1,2
@@ -76,4 +76,6 @@ int main()
     auto tsizemix = extract ( tup, sizemix ());
     static_assert ( std::tuple_size<decltype(tsizemix)>::value == sizemix::size (), "tsizemix size wrong");
     assert ( tsizemix == std::make_tuple ( 11, 11, 12, 13, 15 ));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
index 44ffb017876..248b346e33a 100644
--- a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER > 11
 
@@ -36,4 +36,6 @@ int main()
 X
 
 #endif  // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
index 653d2988a7c..a8e14c9a9cd 100644
--- a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
@@ -22,7 +22,7 @@
 #include <cstddef>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 //  Make a few of sequences
     using int3    = std::integer_sequence<int, 3, 2, 1>;
@@ -42,4 +42,6 @@ int main()
 
     static_assert ( std::is_same<bool0::value_type, bool>::value, "bool0 type wrong" );
     static_assert ( bool0::size() == 0, "bool0 size wrong" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
index 2f2a6608b2c..ec2e8cc7c2c 100644
--- a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   typedef std::make_integer_sequence<int, -3> MakeSeqT;
 
@@ -33,4 +33,6 @@ int main()
 #else
     MakeSeqT i; // expected-error@utility:* {{static_assert failed "std::make_integer_sequence must have a non-negative sequence length"}}
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
index 3c522c73bf9..50b49dd725e 100644
--- a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
@@ -17,7 +17,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_same<std::make_integer_sequence<int, 0>, std::integer_sequence<int>>::value, "");
     static_assert(std::is_same<std::make_integer_sequence<int, 1>, std::integer_sequence<int, 0>>::value, "");
@@ -28,4 +28,6 @@ int main()
     static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 1>, std::integer_sequence<unsigned long long, 0>>::value, "");
     static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 2>, std::integer_sequence<unsigned long long, 0, 1>>::value, "");
     static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 3>, std::integer_sequence<unsigned long long, 0, 1, 2>>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
index b095dbfaf16..1a58726a854 100644
--- a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
@@ -15,7 +15,9 @@
 
 void test(std::allocator_arg_t) {}
 
-int main()
+int main(int, char**)
 {
     test(std::allocator_arg);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp
index 60f267fa5e3..47cfbb0494b 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp
@@ -42,9 +42,11 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
     A<int> a;
     std::allocator_traits<A<int> >::allocate(a, 10);          // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
     std::allocator_traits<A<int> >::allocate(a, 10, nullptr); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp
index a892be03d9d..0ac2f266e81 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp
@@ -33,7 +33,7 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
   {
     A<int> a;
@@ -45,4 +45,6 @@ int main()
     Alloc a;
     assert(std::allocator_traits<Alloc >::allocate(a, 10) == reinterpret_cast<VT*>(static_cast<std::uintptr_t>(0xDEADBEEF)));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp
index 9d4631740b0..e9524716398 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp
@@ -53,7 +53,7 @@ struct B
 };
 
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
   {
@@ -77,4 +77,6 @@ int main()
     Alloc b;
     assert(std::allocator_traits<Alloc >::allocate(b, 11, nullptr) == reinterpret_cast<VT*>(static_cast<std::uintptr_t>(0xFEADBEEF)));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
index 252d99a7a74..67a2e8f4ac8 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
@@ -81,7 +81,7 @@ struct A2
 
 int A2::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A0::count = 0;
@@ -149,4 +149,6 @@ int main()
         assert(b_construct == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
index 94f10b64dba..c738416e01d 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
@@ -36,7 +36,7 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
   {
     A<int> a;
@@ -51,4 +51,6 @@ int main()
     std::allocator_traits<Alloc >::deallocate(a, reinterpret_cast<VT*>(static_cast<std::uintptr_t>(0xDEADBEEF)), 10);
     assert(called == 1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp
index 677c647a27d..70890d8512f 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp
@@ -54,7 +54,7 @@ struct A0
 
 int A0::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A0::count = 0;
@@ -86,4 +86,6 @@ int main()
         assert(b_destroy == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp
index a51ec6e95ac..b758c9add8c 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp
@@ -42,7 +42,7 @@ struct B
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         B<int> b;
@@ -74,4 +74,6 @@ int main()
         static_assert(noexcept(std::allocator_traits<std::allocator<int>>::max_size(a)) == true, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp
index 9594531dad9..be837670dd3 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp
@@ -47,7 +47,7 @@ struct B
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         A<int> a;
@@ -73,4 +73,6 @@ int main()
         assert(std::allocator_traits<B<int> >::select_on_container_copy_construction(b).id == 100);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp
index f153d95b4aa..756958b584f 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp
@@ -55,7 +55,7 @@ private:
   typedef void const_pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::const_pointer, Ptr<const char> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::const_pointer, const char*>::value), "");
@@ -63,4 +63,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::const_pointer, const char*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp
index 3acedde6544..4fcc2fb7c15 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp
@@ -57,7 +57,7 @@ private:
     typedef int const_void_pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::const_void_pointer, Ptr<const void> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::const_void_pointer, const void*>::value), "");
@@ -65,4 +65,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::const_void_pointer, const void*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp
index b0ee1635083..35721f1cbba 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp
@@ -66,7 +66,7 @@ struct pointer_traits<C<char>::pointer>
 
 }
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::difference_type, short>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::difference_type, std::ptrdiff_t>::value), "");
@@ -74,4 +74,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::difference_type, std::ptrdiff_t>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp
index fae61849331..42b0fbab19c 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp
@@ -39,7 +39,7 @@ struct C
     int not_empty_;  // some random member variable
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::is_always_equal, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::is_always_equal, std::true_type>::value), "");
@@ -48,4 +48,6 @@ int main()
     static_assert((std::is_same<std::allocator_traits<A<const char> >::is_always_equal, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<const char> >::is_always_equal, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<C<const char> >::is_always_equal, std::false_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp
index 60f3d257afd..58b306660a8 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp
@@ -43,11 +43,13 @@ private:
     typedef void pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::pointer, Ptr<char> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::pointer, char*>::value), "");
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::pointer, char*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp
index c8451b2a975..b049159e2d1 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp
@@ -43,11 +43,13 @@ private:
     typedef std::true_type propagate_on_container_copy_assignment;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::propagate_on_container_copy_assignment, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::propagate_on_container_copy_assignment, std::false_type>::value), "");
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::propagate_on_container_copy_assignment, std::false_type>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp
index 7c58ac8811b..602ba96d5c1 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp
@@ -44,11 +44,13 @@ private:
 };
 
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::propagate_on_container_move_assignment, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::propagate_on_container_move_assignment, std::false_type>::value), "");
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::propagate_on_container_move_assignment, std::false_type>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp
index 7a6bcd460a6..5ae53015fa3 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp
@@ -42,11 +42,13 @@ private:
     typedef std::true_type propagate_on_container_swap;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::propagate_on_container_swap, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::propagate_on_container_swap, std::false_type>::value), "");
  #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::propagate_on_container_swap, std::false_type>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp
index eaadeb17048..d0d8476a89a 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp
@@ -80,7 +80,7 @@ struct G {
     };
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<A<char> >::rebind_alloc<double>, ReboundA<double> >::value), "");
@@ -97,4 +97,6 @@ int main()
     static_assert((std::is_same<std::allocator_traits<D<int, char> >::rebind_alloc<double>::other, D<double, char> >::value), "");
     static_assert((std::is_same<std::allocator_traits<E<char> >::rebind_alloc<double>::other, E<double> >::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp
index 42b29a39c7b..cd74671390e 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp
@@ -62,7 +62,7 @@ struct pointer_traits<C<char>::pointer>
 
 }
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::size_type, unsigned short>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::size_type,
@@ -72,4 +72,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::size_type, unsigned short>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp
index 687d892f0cf..55954dc7091 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp
@@ -56,7 +56,7 @@ private:
     typedef void void_pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::void_pointer, Ptr<void> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::void_pointer, void*>::value), "");
@@ -64,4 +64,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::void_pointer, void*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp
index d5977f0a28f..840ad820e1f 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp
@@ -24,7 +24,9 @@ struct A
     typedef T value_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::allocator_type, A<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp
index 475ab04b839..01aac9445c8 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp
@@ -62,7 +62,7 @@ struct E
     template <class U> struct rebind {typedef ReboundA<U> otter;};
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<A<char> >::rebind_traits<double>, std::allocator_traits<ReboundA<double> > >::value), "");
@@ -77,4 +77,6 @@ int main()
     static_assert((std::is_same<std::allocator_traits<D<int, char> >::rebind_traits<double>::other, std::allocator_traits<D<double, char> > >::value), "");
     static_assert((std::is_same<std::allocator_traits<E<char> >::rebind_traits<double>::other, std::allocator_traits<E<double> > >::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp
index dec3a41e374..047d40d5c89 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp
@@ -24,7 +24,9 @@ struct A
     typedef T value_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::value_type, char>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp
index 5b7f710eab0..d9d4fc3d837 100644
--- a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp
@@ -47,7 +47,7 @@ test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<false, int, std::allocator<int> >();
     test<true, std::vector<int>, std::allocator<int> >();
@@ -71,4 +71,6 @@ int main()
 // #if TEST_STD_VER >= 11
 //     static_assert((!std::uses_allocator<E, int>::value), "");
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp
index a8d90b1ce6f..7e6c6780070 100644
--- a/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp
@@ -8,6 +8,8 @@
 
 // <cstdlib> and <cstring> are already tested elsewhere
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp
index 7aa2dbfeb03..57946be085a 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::allocator<char> AC;
@@ -46,4 +46,6 @@ int main()
     (void) a3;
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp
index b38daf8e912..63412bce1f4 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp
@@ -21,10 +21,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::allocator<int> a1;
     std::allocator<int> a2;
     assert(a1 == a2);
     assert(!(a1 != a2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp
index bb1bb4f11ee..c4ff55d0eab 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp
@@ -31,8 +31,10 @@ struct A
     void operator&() const {}
 };
 
-int main()
+int main(int, char**)
 {
     test_address<int>();
     test_address<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp
index df4124f51ed..889804f3b71 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp
@@ -19,9 +19,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::allocator<int> a;
     a.allocate(3);          // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
     a.allocate(3, nullptr); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp
index 14e5a8a3c79..8392cbdb709 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp
@@ -99,7 +99,7 @@ void test_aligned() {
   }
 }
 
-int main() {
+int main(int, char**) {
     test_aligned<1>();
     test_aligned<2>();
     test_aligned<4>();
@@ -108,4 +108,6 @@ int main() {
     test_aligned<MaxAligned>();
     test_aligned<OverAligned>();
     test_aligned<OverAligned * 2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp
index 09a9bd912d0..685e02ef393 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp
@@ -39,8 +39,10 @@ void test()
     test_max<T> ((size_t) -1);                     // way too large
 }
 
-int main()
+int main(int, char**)
 {
     test<double>();
     LIBCPP_ONLY(test<const double>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp
index 322881b1536..96954e04b08 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp
@@ -53,7 +53,7 @@ public:
 };
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     {
     std::allocator<A> a;
@@ -139,4 +139,6 @@ int main()
     assert(move_only_constructed == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp
index 50076ce02f4..c2094bc044a 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp
@@ -18,9 +18,11 @@
 
 int new_called = 0;
 
-int main()
+int main(int, char**)
 {
     const std::allocator<int> a;
     std::size_t M = a.max_size();
     assert(M > 0xFFFF && M <= (std::numeric_limits<std::size_t>::max() / sizeof(int)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp
index 375b96f831b..bc89c62a847 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp
@@ -108,7 +108,7 @@ void test_void_pointer()
 
 struct Foo { int x; };
 
-int main()
+int main(int, char**)
 {
     test_pointer<std::allocator<char>> ();
     test_pointer<std::allocator<int>> ();
@@ -117,7 +117,9 @@ int main()
     test_void_pointer<std::allocator<char>> ();
     test_void_pointer<std::allocator<int>> ();
     test_void_pointer<std::allocator<Foo>> ();
+
+  return 0;
 }
 #else
-int main() {}
+int main(int, char**) { return 0; }
 #endif
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp
index 9cd5815645d..0bff67efbd9 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp
@@ -33,7 +33,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator<char>::size_type, std::size_t>::value), "");
     static_assert((std::is_same<std::allocator<char>::difference_type, std::ptrdiff_t>::value), "");
@@ -53,4 +53,6 @@ int main()
     a2 = a;
     std::allocator<int> a3 = a2;
     ((void)a3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp
index 1f13c8be6ca..528902d2112 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp
@@ -22,7 +22,7 @@
 #include <memory>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator<void>::pointer, void*>::value), "");
     static_assert((std::is_same<std::allocator<void>::const_pointer, const void*>::value), "");
@@ -32,4 +32,6 @@ int main()
     std::allocator<void> a;
     std::allocator<void> a2 = a;
     a2 = a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp b/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp
index 0fd45fd913c..7d55974dd93 100644
--- a/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp
@@ -99,7 +99,7 @@ struct pointer_traits<::P4>
 int n = 0;
 static_assert(std::to_address(&n) == &n);
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     ASSERT_NOEXCEPT(std::to_address(&i));
@@ -116,4 +116,6 @@ int main()
     P4 p4(&i);
     ASSERT_NOEXCEPT(std::to_address(p4));
     assert(std::to_address(p4) == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp
index 867bd46cd29..3eaedab1670 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp
@@ -18,7 +18,9 @@
 #include <memory>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<double*>::difference_type, std::ptrdiff_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp
index 42db90ff6ef..505881ddeea 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp
@@ -18,7 +18,9 @@
 #include <memory>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<const short*>::element_type, const short>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp
index 4a74b5d5894..110a993dc66 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp
@@ -24,8 +24,10 @@ struct A
     typedef char difference_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<A>::pointer, A>::value), "");
     static_assert((std::is_same<std::pointer_traits<int*>::pointer, int*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp
index 0b412dac463..9e6a48930e2 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp
@@ -34,7 +34,7 @@ public:
         {return A(&et);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         int i = 0;
@@ -45,4 +45,6 @@ int main()
     {
         (std::pointer_traits<A<void> >::element_type)0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp
index 7e08235399e..d4d763c69ea 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp
@@ -52,7 +52,7 @@ private:
   typedef int difference_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<A>::difference_type, char>::value), "");
     static_assert((std::is_same<std::pointer_traits<B>::difference_type, std::ptrdiff_t>::value), "");
@@ -62,4 +62,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::pointer_traits<F<int>>::difference_type, std::ptrdiff_t>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp
index 8184d2d0027..c0efdeab0b3 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp
@@ -53,7 +53,7 @@ private:
   typedef int element_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<A>::element_type, char>::value), "");
     static_assert((std::is_same<std::pointer_traits<B<int> >::element_type, char>::value), "");
@@ -64,4 +64,6 @@ int main()
     static_assert((std::is_same<std::pointer_traits<F<double>>::element_type, double>::value), "");
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp
index 407f4bcfb9f..a79f3391664 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp
@@ -81,7 +81,7 @@ struct G
 #endif
 
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::pointer_traits<A<int*> >::rebind<double*>, A<double*> >::value), "");
@@ -101,4 +101,6 @@ int main()
     static_assert((std::is_same<std::pointer_traits<D<char, int> >::rebind<double>::other, D1<double, int> >::value), "");
     static_assert((std::is_same<std::pointer_traits<E<char, int> >::rebind<double>::other, E<double, int> >::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp
index 968d3ee1e72..e9b858c7fd9 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp
@@ -35,9 +35,11 @@ bool check() {
     return true;
 }
 
-int main() {
+int main(int, char**) {
     check();
 #if TEST_STD_VER > 17
     static_assert(check(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp
index 823d4f11f23..f64213c9b88 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp
@@ -20,11 +20,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::pointer_traits<int*>::rebind<double>, double*>::value), "");
 #else
     static_assert((std::is_same<std::pointer_traits<int*>::rebind<double>::other, double*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp b/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp
index c7a181eb79e..3d0216cce53 100644
--- a/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp
+++ b/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp
@@ -13,7 +13,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const unsigned N = 20;
     char buf[N];
@@ -80,4 +80,6 @@ int main()
     assert(p == &buf[0]);
     assert(r == nullptr);
     assert(s == N);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp
index 956e6b1187c..f6310c7bc91 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp
@@ -26,7 +26,7 @@ struct nothing {
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
     int i;
@@ -47,4 +47,6 @@ int main()
     };
     assert(std::addressof(n) == (void*)std::addressof(i));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp
index c12bf41e8ea..f7033014d37 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp
@@ -15,11 +15,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER > 14
     const int *p = std::addressof<const int>(0);
 #else
 #error
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
index c042dd5c37b..f14a0e7fc89 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
@@ -32,10 +32,12 @@ constexpr int i = 0;
 constexpr double d = 0.0;
 constexpr A a{};
 
-int main()
+int main(int, char**)
 {
     static_assert(std::addressof(i) == &i, "");
     static_assert(std::addressof(d) == &d, "");
     constexpr const A* ap = std::addressof(a);
     static_assert(&ap->n == &a.n, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp
index f812bb85a62..4dbc20aba39 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp
@@ -30,7 +30,7 @@ struct Counted {
 };
 int Counted::count = 0;
 
-int main()
+int main(int, char**)
 {
     using It = forward_iterator<Counted*>;
     const int N = 5;
@@ -43,4 +43,6 @@ int main()
     assert(Counted::count == 4);
     std::destroy(It(p), It(p + 4));
     assert(Counted::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp
index 28450faa10f..d505222b02d 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp
@@ -41,7 +41,7 @@ struct DCounted : VCounted {
     friend void operator&(DCounted) = delete;
 };
 
-int main()
+int main(int, char**)
 {
     {
     void* mem1 = std::malloc(sizeof(Counted));
@@ -74,4 +74,6 @@ int main()
     std::free(mem1);
     std::free(mem2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp
index 90836b23355..0dcc8e5a657 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp
@@ -30,7 +30,7 @@ struct Counted {
 };
 int Counted::count = 0;
 
-int main()
+int main(int, char**)
 {
     using It = forward_iterator<Counted*>;
     const int N = 5;
@@ -45,4 +45,6 @@ int main()
     It it = std::destroy_n(It(p), 4);
     assert(it == It(p+4));
     assert(Counted::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp
index bd9ef7b403f..67dd6fbd298 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp
@@ -103,9 +103,11 @@ void test_value_initialized()
     assert(pool[4] == -1);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp
index d2f6e094a85..1052355a4f2 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp
@@ -107,9 +107,11 @@ void test_value_initialized()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp
index 50ce1224848..5dfcd83fe9b 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp
@@ -102,9 +102,11 @@ void test_value_initialized()
     assert(pool[4] == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp
index 4d89f9cac4c..e43102ba4aa 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp
@@ -107,8 +107,10 @@ void test_value_initialized()
     assert(pool[4] == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp
index b81d561e089..2618bd5339c 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp
@@ -47,7 +47,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -85,4 +85,6 @@ int main()
         }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp
index c3f46bebe67..1a237a7929d 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp
@@ -47,7 +47,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -84,4 +84,6 @@ int main()
         assert(  p[i].i_ == i);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp
index 5c177663e40..4dfde4f6e87 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp
@@ -46,7 +46,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -84,4 +84,6 @@ int main()
     }
 
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp
index f7790fc4519..1996ec6c6ff 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp
@@ -47,7 +47,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -81,4 +81,6 @@ int main()
     for (int i = 0; i < N; ++i)
         assert(bp[i].i_ == 23);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp
index a0717e61b2c..e17f5734bb2 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp
@@ -107,7 +107,9 @@ void test_counted()
     assert(Counted::count == 0);
 }
 
-int main() {
+int main(int, char**) {
     test_counted();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp
index 75538407421..ee364aaf5b9 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp
@@ -109,8 +109,10 @@ void test_counted()
     assert(Counted::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp
index 531158ba158..5355d09ac26 100644
--- a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp
+++ b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp
@@ -36,7 +36,7 @@ public:
     A* operator& () DELETE_FUNCTION;
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 14
     typedef std::aligned_storage<3*sizeof(A), std::alignment_of<A>::value>::type
@@ -54,4 +54,6 @@ int main()
         assert(it.base() == ap + 1);  // next place to write
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp
index 90bb956fc03..2b9b33fd9b9 100644
--- a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp
@@ -36,7 +36,7 @@ public:
     A* operator& () DELETE_FUNCTION;
 };
 
-int main()
+int main(int, char**)
 {
     {
     typedef A S;
@@ -67,4 +67,6 @@ int main()
     assert(ap->get() == 1); // original value
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp b/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
index fd818577b06..db71c69bf26 100644
--- a/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
+++ b/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
@@ -25,10 +25,12 @@ struct alignas(32) A {
     int field;
 };
 
-int main()
+int main(int, char**)
 {
     std::pair<A*, std::ptrdiff_t> ip = std::get_temporary_buffer<A>(5);
     assert(!(ip.first == nullptr) ^ (ip.second == 0));
     assert(reinterpret_cast<uintptr_t>(ip.first) % alignof(A) == 0);
     std::return_temporary_buffer(ip.first);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp b/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp
index 22efde4af8f..32a58e5a657 100644
--- a/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp
@@ -19,10 +19,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::pair<int*, std::ptrdiff_t> ip = std::get_temporary_buffer<int>(5);
     assert(ip.first);
     assert(ip.second == 5);
     std::return_temporary_buffer(ip.first);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp
index c9d1c8b4697..bc6846fe7f5 100644
--- a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp
+++ b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp
@@ -26,9 +26,11 @@
 #include "min_allocator.h"
 #include "deleter_types.h"
 
-int main()
+int main(int, char**)
 {
     std::unique_ptr<int, PointerDeleter<int>> p;
     std::ostringstream os;
     os << p; // expected-error {{invalid operands to binary expression}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp
index e350a0385d6..b9b158a9d2b 100644
--- a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp
+++ b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp
@@ -21,11 +21,13 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::unique_ptr<int> p(new int(3));
     std::ostringstream os;
     assert(os.str().empty());
     os << p;
     assert(!os.str().empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp
index 5c99a9721a0..a2b6cf22ed8 100644
--- a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp
@@ -13,10 +13,12 @@
 
 #include <memory>
 
-int main()
+int main(int, char**)
 {
     char* p = new char[10];
     std::declare_no_pointers(p, 10);
     std::undeclare_no_pointers(p, 10);
     delete [] p;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp
index 4a71817d403..c923089fa97 100644
--- a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp
@@ -14,10 +14,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int* p = new int;
     std::declare_reachable(p);
     assert(std::undeclare_reachable(p) == p);
     delete p;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp b/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp
index 4fc2e010f79..2fea98364b4 100644
--- a/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp
@@ -22,7 +22,7 @@ void test_pr26961() {
   assert(d == std::get_pointer_safety());
 }
 
-int main()
+int main(int, char**)
 {
   {
     std::pointer_safety r = std::get_pointer_safety();
@@ -33,4 +33,6 @@ int main()
   {
     test_pr26961();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
index 0f7c44fd8fd..fe7567eebc1 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
@@ -52,7 +52,7 @@ struct PrivateBase : private std::enable_shared_from_this<PrivateBase> {
 };
 
 
-int main()
+int main(int, char**)
 {
     {  // https://bugs.llvm.org/show_bug.cgi?id=18843
     std::shared_ptr<T const> t1(new T);
@@ -167,4 +167,6 @@ int main()
         assert(my_weak.lock().get() == ptr);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
index bd7f644c3ec..440fa8ac480 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
index 8db542c0794..34717ad4256 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
@@ -25,7 +25,7 @@
 struct A {};
 #endif
 
-int main()
+int main(int, char**)
 {
   {
     int* ptr = new int;
@@ -40,4 +40,6 @@ int main()
     test_hash_enabled_for_type<std::shared_ptr<A>>();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
index 4f942f6c2d9..5cae6ca7d45 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
@@ -60,7 +60,7 @@ struct A {};
 
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
   {
     int* ptr = new int;
@@ -99,4 +99,6 @@ int main()
 #endif
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
index 45c82c4bafa..7737cfd4da0 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -51,4 +51,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
index d1589aaddba..9198ca68cd8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -56,4 +56,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp
index fb09a19fd05..da52811c9c0 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -51,4 +51,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
index 2a9b6ce1244..703bf008f4f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -56,4 +56,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp
index cf6ad5b0037..b51a24aefb9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -37,4 +37,6 @@ int main()
         assert(*p == 3);
         assert(*r == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
index f177420fe94..b59b515a5c2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -37,4 +37,6 @@ int main()
         assert(*p == 3);
         assert(*r == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp
index 3b267f99d09..e8bb64dccb6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp
@@ -23,10 +23,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<int> p(new int(3));
         assert(std::atomic_is_lock_free(&p) == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp
index b36580ef217..63416faf329 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp
@@ -28,11 +28,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(3));
         std::shared_ptr<int> q = std::atomic_load(&p);
         assert(*q == *p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
index 40f6b49d6c6..0708f874b26 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
@@ -28,11 +28,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<int> p(new int(3));
         std::shared_ptr<int> q = std::atomic_load_explicit(&p, std::memory_order_relaxed);
         assert(*q == *p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp
index 3c6de40f117..42d7099a9df 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p;
@@ -36,4 +36,6 @@ int main()
         std::atomic_store(&p, r);
         assert(*p == *r);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
index dd4001a82ff..7da4de3fa47 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p;
@@ -36,4 +36,6 @@ int main()
         std::atomic_store_explicit(&p, r, std::memory_order_seq_cst);
         assert(*p == *r);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp
index 4a96f8181b2..c3aedd5b1ad 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp
@@ -22,10 +22,12 @@
 
 struct A;  // purposefully incomplete
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::shared_ptr<A>::element_type, A>::value), "");
 #if TEST_STD_VER > 14
     static_assert((std::is_same<std::shared_ptr<A>::weak_type, std::weak_ptr<A>>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp
index babf1c6ee5b..209e3fe71af 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         {
@@ -63,4 +63,6 @@ int main()
         std::default_delete<A>* d = std::get_deleter<std::default_delete<A> >(p);
         assert(d == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
index 69ad9513b6c..a154a121c7f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
@@ -40,7 +40,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::auto_ptr<A> pA(new A);
@@ -110,4 +110,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
index 6d2000c1375..e362f4d8d4e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -117,4 +117,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
index 23b587d0b7d..2b666315ef2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -117,4 +117,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
index a3ba5877f49..6787c33c297 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
@@ -41,7 +41,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -119,4 +119,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
index 8c63b14b27d..e921a099189 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
@@ -41,7 +41,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -119,4 +119,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
index b7fc447b057..4abe371bc07 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_ptr<A> pA(new A);
@@ -109,4 +109,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
index 53955aaa218..51e2949b6c6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<const A> pA(new A);
@@ -53,4 +53,6 @@ int main()
         assert(pB.get() == pA.get());
         assert(!pB.owner_before(pA) && !pA.owner_before(pB));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
index c27f9503b62..76009b96abd 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<B> pB(new A);
@@ -53,4 +53,6 @@ int main()
         assert(pA.get() == 0);
         assert(pA.use_count() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
index ec72834d5cd..9ea544fee01 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -65,4 +65,6 @@ int main()
         assert(pB.get() == pA.get());
         assert(!pB.owner_before(pA) && !pA.owner_before(pB));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp
index 6936744c1ab..98b5bbf0d67 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp
@@ -40,7 +40,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int(1));
     assert(!(p1 == nullptr));
@@ -65,4 +65,6 @@ int main()
     assert(!(nullptr > p2));
     assert( (p2 >= nullptr));
     assert( (nullptr >= p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp
index 1257ea65fd8..e25ba611744 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp
@@ -18,7 +18,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     int* ptr1(new int);
     int* ptr2(new int);
@@ -27,4 +27,6 @@ int main()
     const std::shared_ptr<int> p3(ptr2, do_nothing);
     assert(p1 != p2);
     assert(p2 == p3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp
index 15e13688b4d..fdef32d518a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp
@@ -17,7 +17,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     int* ptr1(new int);
     int* ptr2(new int);
@@ -26,4 +26,6 @@ int main()
     const std::shared_ptr<int> p3(ptr2, do_nothing);
     assert((p1 < p2) == (ptr1 < ptr2));
     assert(!(p2 < p3) && !(p3 < p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
index 6558e230dff..282ddd0e0ea 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
@@ -43,7 +43,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::auto_ptr<A> ptr(new A);
@@ -94,4 +94,6 @@ int main()
     assert(A::count == 0);
     assert(globalMemCounter.checkOutstandingNewEq(0));
 #endif // !defined(TEST_HAS_NO_EXCEPTIONS) && !defined(DISABLE_NEW_COUNT)
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp
index c70e537a9af..247ca0fa924 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp
@@ -13,9 +13,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<int> p;
     assert(p.use_count() == 0);
     assert(p.get() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp
index a46b31aa5a9..f29dd1cf7ea 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp
@@ -13,9 +13,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<int> p(nullptr);
     assert(p.use_count() == 0);
     assert(p.get() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp
index 9644e4f0f99..ee5861122bf 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     std::shared_ptr<A> p(nullptr, test_deleter<A>(3));
@@ -43,4 +43,6 @@ int main()
     assert(A::count == 0);
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp
index bc1d3584e1e..0881e8cf42d 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     std::shared_ptr<A> p(nullptr, test_deleter<A>(3), test_allocator<A>(5));
@@ -81,4 +81,6 @@ int main()
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp
index 1948c6860ab..4700df0085c 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     try
     {
@@ -43,4 +43,6 @@ int main()
         assert(test_allocator<A>::count == 0);
         assert(test_allocator<A>::alloc_count == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp
index 075cadf43d6..7d2628d60dc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp
@@ -37,7 +37,7 @@ struct A
 int A::count = 0;
 
 
-int main()
+int main(int, char**)
 {
     globalMemCounter.throw_after = 0;
     try
@@ -51,4 +51,6 @@ int main()
         assert(test_deleter<A>::count == 0);
         assert(test_deleter<A>::dealloc_count == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp
index 67f0ffd2a80..b55d764a6c4 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp
@@ -24,7 +24,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     A* ptr = new A;
@@ -42,4 +42,6 @@ int main()
     assert(p.get() == ptr);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp
index 120171456be..fd98193826e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     A* ptr = new A;
@@ -44,4 +44,6 @@ int main()
     assert(A::count == 0);
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp
index 79a0bc84a39..0ec18a7aebd 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp
@@ -28,7 +28,7 @@ struct A
 int A::count = 0;
 
 
-int main()
+int main(int, char**)
 {
     {
     A* ptr = new A;
@@ -85,4 +85,6 @@ int main()
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp
index ad020f89fd3..5f2984c7e22 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     A* ptr = new A;
     try
@@ -44,4 +44,6 @@ int main()
         assert(test_allocator<A>::count == 0);
         assert(test_allocator<A>::alloc_count == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp
index 6af99aaf55e..da12e42ca0b 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp
@@ -34,7 +34,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     A* ptr = new A;
     globalMemCounter.throw_after = 0;
@@ -50,4 +50,6 @@ int main()
         assert(test_deleter<A>::dealloc_count == 1);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp
index 95da6f69106..15e776003d9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp
@@ -33,7 +33,7 @@ struct A
 int A::count = 0;
 
 
-int main()
+int main(int, char**)
 {
     A* ptr = new A;
     assert(A::count == 1);
@@ -48,4 +48,6 @@ int main()
         assert(A::count == 0);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp
index 44a5be4714b..091782f02f3 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -58,4 +58,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
index 3b7279087ff..01a74898f9c 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
@@ -50,7 +50,7 @@ struct C
 
 int C::count = 0;
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::shared_ptr<A>, std::shared_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::shared_ptr<B>, std::shared_ptr<A> >::value), "");
@@ -93,4 +93,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
index 8d3af186e50..cc86d12dfcf 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
@@ -54,7 +54,7 @@ struct C
 
 int C::count = 0;
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::shared_ptr<A>, std::shared_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::shared_ptr<B>, std::shared_ptr<A> >::value), "");
@@ -109,4 +109,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp
index 06a285cd2ce..83a9a9720dc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp
@@ -37,7 +37,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -57,4 +57,6 @@ int main()
     }
     assert(A::count == 0);
     assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp
index d9eef4a2388..86797a047e8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp
@@ -30,7 +30,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -73,4 +73,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
index d235a50b9a1..6fd812fca0a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
@@ -49,7 +49,7 @@ void fn ( const std::shared_ptr<B> &) { assert (false); }
 template <typename T>
 void assert_deleter ( T * ) { assert(false); }
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_ptr<A> ptr(new A);
@@ -97,4 +97,6 @@ int main()
         std::shared_ptr<int> p2(std::move(p)); // should not call deleter when going out of scope
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
index 117a74aaa57..9174f39be37 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
@@ -40,7 +40,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     {
@@ -81,4 +81,6 @@ int main()
     }
     assert(A::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
index 354a23e7015..06c2bba6705 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
@@ -51,7 +51,7 @@ private:
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     int i = 67;
@@ -82,4 +82,6 @@ int main()
     assert(p->get_char() == 'f');
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
index 0783b6e7f1c..00f79cc19d2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
@@ -97,7 +97,7 @@ void test()
     assert(Three::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int i = 67;
@@ -114,4 +114,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<min_allocator<void> >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
index 2535519b9e7..aed060e5790 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
@@ -73,7 +73,7 @@ void test_pointer_to_function() {
 void test_pointer_to_function() {}
 #endif // _LIBCPP_VERSION
 
-int main()
+int main(int, char**)
 {
     int nc = globalMemCounter.outstanding_new;
     {
@@ -107,4 +107,6 @@ int main()
     }
 #endif
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp
index fd5ebdccab3..e17d7424be4 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp
@@ -22,7 +22,9 @@ private:
    S () {};  // ctor is private
 };
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<S> p = std::make_shared<S>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp
index 8ba4a69c3c4..d4d8fb630c9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp
@@ -22,7 +22,9 @@ protected:
    S () {};  // ctor is protected
 };
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<S> p = std::make_shared<S>();  // expected-error-re@memory:* {{static_assert failed{{.*}} "Can't construct object in make_shared"}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp
index c50b68f7097..aa038f7475f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp
@@ -52,9 +52,11 @@ void test(const T &t0)
 
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(true);
     test<int>(3);
     test<double>(5.0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp
index cf3aac86aec..b09550a6eab 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp
@@ -18,11 +18,13 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<int> p(new int(3));
     std::ostringstream os;
     assert(os.str().empty());
     os << p;
     assert(!os.str().empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
index 3943b5892ba..c9df003192b 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
@@ -38,7 +38,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -58,4 +58,6 @@ int main()
         assert(p.get() == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
index 3e91fa3de56..c3582416584 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
@@ -38,7 +38,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -60,4 +60,6 @@ int main()
         assert(p.get() == ptr);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
index 70a2024cce2..e7d457fa139 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -75,4 +75,6 @@ int main()
     assert(A::count == 0);
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
index d4db96826e3..9e2bd101290 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
@@ -40,7 +40,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -84,4 +84,6 @@ int main()
     assert(test_deleter<A>::dealloc_count == 2);
     assert(test_allocator<A>::count == 0);
     assert(test_allocator<A>::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp
index a47e67f04a9..a27949ebb80 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -100,4 +100,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp
index 5f7d6582b6f..77bf3a22e08 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp
@@ -16,7 +16,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<std::pair<int, int> > p(new std::pair<int, int>(3, 4));
     assert(p->first == 3);
@@ -25,4 +25,6 @@ int main()
     p->second = 6;
     assert(p->first == 5);
     assert(p->second == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp
index 4b2a495a89b..a6f75533acb 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp
@@ -15,10 +15,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p(new int(32));
     assert(*p == 32);
     *p = 3;
     assert(*p == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp
index 4c6790f867c..247deb07bb9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp
@@ -15,7 +15,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     const std::shared_ptr<int> p(new int(32));
@@ -25,4 +25,6 @@ int main()
     const std::shared_ptr<int> p;
     assert(!p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp
index c6ae19911c3..497a53b2144 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -26,4 +26,6 @@ int main()
     assert(p1.owner_before(p3) || p3.owner_before(p1));
     assert(p3.owner_before(p1) == p3.owner_before(p2));
     ASSERT_NOEXCEPT(p1.owner_before(p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp
index e857aa6a83d..07c7a064420 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -29,4 +29,6 @@ int main()
     assert(p1.owner_before(w3) || p3.owner_before(w1));
     assert(p3.owner_before(w1) == p3.owner_before(w2));
     ASSERT_NOEXCEPT(p1.owner_before(w2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp
index 14a2fe992f1..dfad3138517 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp
@@ -15,7 +15,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p(new int(32));
     assert(p.unique());
@@ -24,4 +24,6 @@ int main()
     assert(!p.unique());
     }
     assert(p.unique());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp
index b40e4705acf..b0bfcae9ae4 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -101,4 +101,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp
index 2263eb810cb..f5bdb876b46 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp
@@ -19,7 +19,9 @@
 
 struct A;  // purposefully incomplete
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::weak_ptr<A>::element_type, A>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp
index c65755d8ea4..b3cc13d72a8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp
@@ -52,7 +52,7 @@
 
 struct X {};
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -128,4 +128,6 @@ int main()
     assert(s.find(vp) == s.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
index 1362537e030..02f180d3d64 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -57,4 +57,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
index 739165c3cab..f41c391c4c2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> ps(new A);
@@ -74,4 +74,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
index f763dc46395..33b2ddd422a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> ps(new A);
@@ -74,4 +74,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp
index b29623f296a..e5a70abe417 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp
@@ -17,8 +17,10 @@
 
 struct A;
 
-int main()
+int main(int, char**)
 {
     std::weak_ptr<A> p;
     assert(p.use_count() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
index 8aaeab0c904..45be55e66f8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
@@ -50,7 +50,7 @@ struct C
 
 int C::count = 0;
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::shared_ptr<A>, std::weak_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::weak_ptr<B>, std::shared_ptr<A> >::value), "");
@@ -91,4 +91,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
index 351b66323db..658b233c41c 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
@@ -61,7 +61,7 @@ template <class T>
 void sink (std::weak_ptr<T> &&) {}
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> ps(new A);
@@ -112,4 +112,6 @@ int main()
     assert(B::count == 0);
     assert(A::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
index e155e4faa13..4268fda3aba 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
@@ -54,7 +54,7 @@ int C::count = 0;
 template <class T>
 std::weak_ptr<T> source (std::shared_ptr<T> p) { return std::weak_ptr<T>(p); }
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::weak_ptr<A>, std::weak_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::weak_ptr<B>, std::weak_ptr<A> >::value), "");
@@ -104,4 +104,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp
index 7c3bcb6c641..eae249ca1a5 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> p1(new A);
@@ -37,4 +37,6 @@ int main()
         assert(p1.use_count() == 1);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp
index 38b1dee093a..76703d0ddd7 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -45,4 +45,6 @@ int main()
         }
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp
index f2fccb5589d..5fb2dd4f95b 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::weak_ptr<A> wp;
@@ -42,4 +42,6 @@ int main()
         assert(wp.use_count() == 0);
         assert(wp.expired() == (wp.use_count() == 0));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp
index 883de740cce..50ff84318ef 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::weak_ptr<A> wp;
@@ -54,4 +54,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp
index c916a890740..2df6d6a0e32 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp
@@ -15,7 +15,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2(new int);
@@ -23,4 +23,6 @@ int main()
     const std::weak_ptr<int> w2(p2);
 
     bool b = w1 < w2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp
index d8483d9b65e..4d26f5f2b33 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -29,4 +29,6 @@ int main()
     assert(w1.owner_before(p3) || w3.owner_before(p1));
     assert(w3.owner_before(p1) == w3.owner_before(p2));
     ASSERT_NOEXCEPT(w1.owner_before(p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp
index b323da7d503..39993cd8f6a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -29,4 +29,6 @@ int main()
     assert(w1.owner_before(w3) || w3.owner_before(w1));
     assert(w3.owner_before(w1) == w3.owner_before(w2));
     ASSERT_NOEXCEPT(w1.owner_before(w2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp
index e13d5aeaf63..53bc3eb9cd8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -46,4 +46,6 @@ int main()
         }
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp
index a85120ae05f..f3e26dee54e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp
@@ -20,11 +20,13 @@
 #include <cassert>
 #include <cstring>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_weak_ptr>::value), "");
     std::bad_weak_ptr e;
     std::bad_weak_ptr e2 = e;
     e2 = e;
     assert(std::strcmp(e.what(), "bad_weak_ptr") == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp b/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp
index b9037f52704..917f8b919fa 100644
--- a/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER > 14
     typedef std::bool_constant<true> _t;
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<_f::type, _f>::value), "");
     static_assert((_f() == false), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp b/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp
index 89d64875095..f312acad657 100644
--- a/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::integral_constant<int, 5> _5;
     static_assert(_5::value == 5, "");
@@ -47,4 +47,6 @@ int main()
     std::true_type t1;
     std::true_type t2 = t1;
     assert(t2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp b/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp
index 0b9a0362130..e37769576d2 100644
--- a/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp
@@ -19,7 +19,7 @@
 struct True  { static constexpr bool value = true; };
 struct False { static constexpr bool value = false; };
 
-int main()
+int main(int, char**)
 {
     static_assert ( std::conjunction<>::value, "" );
     static_assert ( std::conjunction<std::true_type >::value, "" );
@@ -62,4 +62,6 @@ int main()
 
     static_assert ( std::conjunction_v<True >, "" );
     static_assert (!std::conjunction_v<False>, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp b/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp
index 00a1b306d61..baaed6f03ce 100644
--- a/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp
@@ -19,7 +19,7 @@
 struct True  { static constexpr bool value = true; };
 struct False { static constexpr bool value = false; };
 
-int main()
+int main(int, char**)
 {
     static_assert (!std::disjunction<>::value, "" );
     static_assert ( std::disjunction<std::true_type >::value, "" );
@@ -62,4 +62,6 @@ int main()
 
     static_assert ( std::disjunction_v<True >, "" );
     static_assert (!std::disjunction_v<False>, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp b/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp
index d399a5c84e6..88ca693d31b 100644
--- a/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp
@@ -19,7 +19,7 @@
 struct True  { static constexpr bool value = true; };
 struct False { static constexpr bool value = false; };
 
-int main()
+int main(int, char**)
 {
     static_assert (!std::negation<std::true_type >::value, "" );
     static_assert ( std::negation<std::false_type>::value, "" );
@@ -35,4 +35,6 @@ int main()
 
     static_assert ( std::negation<std::negation<std::true_type >>::value, "" );
     static_assert (!std::negation<std::negation<std::false_type>>::value, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp
index c2b84b35427..ec27581a4f9 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp
@@ -40,7 +40,7 @@ struct B1 : B {};
 struct B2 : B {};
 struct D : private B1, private B2 {};
 
-int main()
+int main(int, char**)
 {
     test_is_base_of<B, D>();
     test_is_base_of<B1, D>();
@@ -53,4 +53,6 @@ int main()
     test_is_not_base_of<B&, D&>();
     test_is_not_base_of<B[3], D[3]>();
     test_is_not_base_of<int, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp
index faffaf6b3d6..b1722b0fcec 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp
@@ -60,7 +60,7 @@ class CannotInstantiate {
   enum { X = T::ThisExpressionWillBlowUp };
 };
 
-int main()
+int main(int, char**)
 {
     // void
     test_is_convertible<void,void> ();
@@ -259,4 +259,6 @@ int main()
     // Ensure that CannotInstantiate is not instantiated by is_convertible when it is not needed.
     // For example CannotInstantiate is instatiated as a part of ADL lookup for arguments of type CannotInstantiate*.
     static_assert((std::is_convertible<CannotInstantiate<int>*, CannotInstantiate<int>*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp
index dab17974bb8..fa0c0c82e8a 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp
@@ -46,7 +46,7 @@ struct Sink {
   void operator()(Args&&...) const {}
 };
 
-int main() {
+int main(int, char**) {
   using AbominableFunc = void(...) const;
 
   //  Non-callable things
@@ -241,4 +241,5 @@ int main() {
   static_assert(std::is_invocable_r_v<void, Fn>, "");
   static_assert(!std::is_invocable_r_v<int, Fn>, "");
 }
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp
index f21e99b02d0..baf64c12f9e 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp
@@ -80,7 +80,7 @@ void test_noexcept_function_pointers() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   using AbominableFunc = void(...) const noexcept;
   //  Non-callable things
   {
@@ -212,4 +212,6 @@ int main() {
     static_assert(!std::is_nothrow_invocable_r_v<int, Fn, int>, "");
   }
   test_noexcept_function_pointers();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp
index 63458055008..739713bf4c2 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp
@@ -56,7 +56,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_same<int, int>();
     test_is_same<void, void>();
@@ -69,4 +69,6 @@ int main()
     test_is_not_same<Class, int*>();
     test_is_not_same<int*, int&>();
     test_is_not_same<int&, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp
index 62699fed46e..a887d52bbc0 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp
@@ -25,7 +25,7 @@ void test_remove_all_extents()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_all_extents<int, int> ();
     test_remove_all_extents<const Enum, const Enum> ();
@@ -39,4 +39,6 @@ int main()
     test_remove_all_extents<const int[2][3], const int> ();
     test_remove_all_extents<int[1][2][3], int> ();
     test_remove_all_extents<const int[1][2][3], const int> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp
index 1c0f9884817..a0b19d6a64a 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp
@@ -26,7 +26,7 @@ void test_remove_extent()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_remove_extent<int, int> ();
     test_remove_extent<const Enum, const Enum> ();
@@ -40,4 +40,6 @@ int main()
     test_remove_extent<const int[2][3], const int[3]> ();
     test_remove_extent<int[1][2][3], int[2][3]> ();
     test_remove_extent<const int[1][2][3], const int[2][3]> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp
index c7fb61232b3..edde6565744 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp
@@ -32,7 +32,7 @@ void test_add_const()
     test_add_const_imp<const volatile T, const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_add_const<void>();
     test_add_const<int>();
@@ -41,4 +41,6 @@ int main()
     test_add_const<const int&>();
     test_add_const<int*>();
     test_add_const<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp
index 0662c9dd400..5621bbf4263 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp
@@ -32,7 +32,7 @@ void test_add_cv()
     test_add_cv_imp<const volatile T, const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_add_cv<void>();
     test_add_cv<int>();
@@ -41,4 +41,6 @@ int main()
     test_add_cv<const int&>();
     test_add_cv<int*>();
     test_add_cv<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp
index 476a780a423..6dfaa60f894 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp
@@ -32,7 +32,7 @@ void test_add_volatile()
     test_add_volatile_imp<const volatile T, const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_add_volatile<void>();
     test_add_volatile<int>();
@@ -41,4 +41,6 @@ int main()
     test_add_volatile<const int&>();
     test_add_volatile<int*>();
     test_add_volatile<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp
index d53d6f805f9..3c927e7c92e 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp
@@ -32,7 +32,7 @@ void test_remove_const()
     test_remove_const_imp<const volatile T, volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_const<void>();
     test_remove_const<int>();
@@ -41,4 +41,6 @@ int main()
     test_remove_const<const int&>();
     test_remove_const<int*>();
     test_remove_const<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp
index 569b9642d35..2dc8d26e0e3 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp
@@ -32,7 +32,7 @@ void test_remove_cv()
     test_remove_cv_imp<const volatile T, T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_cv<void>();
     test_remove_cv<int>();
@@ -41,4 +41,6 @@ int main()
     test_remove_cv<const int&>();
     test_remove_cv<int*>();
     test_remove_cv<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp
index 358d2fa8bfd..fb45d94395e 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp
@@ -32,7 +32,7 @@ void test_remove_volatile()
     test_remove_volatile_imp<const volatile T, const T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_volatile<void>();
     test_remove_volatile<int>();
@@ -41,4 +41,6 @@ int main()
     test_remove_volatile<const int&>();
     test_remove_volatile<int*>();
     test_remove_volatile<volatile int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp
index 08c0b8bb162..3e80402e814 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp
@@ -17,7 +17,7 @@
 #include <cstddef>       // for std::max_align_t
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::aligned_storage<10, 1 >::type T1;
@@ -285,4 +285,6 @@ int main()
     static_assert(std::alignment_of<T1>::value == 8, "");
     static_assert(sizeof(T1) == 16, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp
index 2564f112005..cf9fe632dd3 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp
@@ -16,7 +16,9 @@
 
 class A; // Incomplete
 
-int main()
+int main(int, char**)
 {
     typedef std::aligned_union<10, A>::type T1;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp
index 800a0074cb9..789fd12a9ff 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::aligned_union<10, char >::type T1;
@@ -111,4 +111,6 @@ int main()
     static_assert(std::alignment_of<T1>::value == 4, "");
     static_assert(sizeof(T1) == 4, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp
index 70d2ddf095a..f96603b30b6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp
@@ -234,7 +234,7 @@ static_assert(is_same<typename result_of<PMD(const S*)>::type, const char&>::val
 } // namespace note_b_example
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::common_type<int>::type, int>::value), "");
     static_assert((std::is_same<std::common_type<char>::type, char>::value), "");
@@ -307,4 +307,6 @@ int main()
     static_assert((std::is_same<std::common_type<const int, int>::type,       int>::value), "");
     static_assert((std::is_same<std::common_type<int, const int>::type,       int>::value), "");
     static_assert((std::is_same<std::common_type<const int, const int>::type, int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp
index b408dfb2c2c..288376ac93c 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp
@@ -14,7 +14,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::conditional<true, char, int>::type, char>::value), "");
     static_assert((std::is_same<std::conditional<false, char, int>::type, int>::value), "");
@@ -22,4 +22,6 @@ int main()
     static_assert((std::is_same<std::conditional_t<true, char, int>, char>::value), "");
     static_assert((std::is_same<std::conditional_t<false, char, int>, int>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp
index a6f85e921b8..94d9720399f 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp
@@ -23,7 +23,7 @@ void test_decay()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_decay<void, void>();
     test_decay<int, int>();
@@ -38,4 +38,6 @@ int main()
     test_decay<int(int)  &, int(int)  &>();
     test_decay<int(int) &&, int(int) &&>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp
index c7b0763e1d8..c033d1aef26 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp
@@ -12,7 +12,9 @@
 
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::enable_if<false>::type A;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp
index bb107d90ad9..c02c6efdb2d 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp
@@ -14,7 +14,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::enable_if<true>::type, void>::value), "");
     static_assert((std::is_same<std::enable_if<true, int>::type, int>::value), "");
@@ -22,4 +22,6 @@ int main()
     static_assert((std::is_same<std::enable_if_t<true>, void>::value), "");
     static_assert((std::is_same<std::enable_if_t<true, int>, int>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp
index 70aa3e2121f..79382d35993 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp
@@ -13,7 +13,9 @@
 
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::enable_if_t<false> A;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp
index e67cab8e4a8..e6a01a77ac5 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp
@@ -23,7 +23,7 @@ void test_remove_cvref()
     static_assert((std::is_same<         std::remove_cvref_t<T>,     U>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_cvref<void, void>();
     test_remove_cvref<int, int>();
@@ -48,4 +48,6 @@ int main()
     test_remove_cvref<int(int) volatile, int(int) volatile>();
     test_remove_cvref<int(int)  &, int(int)  &>();
     test_remove_cvref<int(int) &&, int(int) &&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
index 313691f3228..34dd6d8ea03 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
@@ -92,7 +92,7 @@ void test_no_result()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     typedef NotDerived ND;
     { // functor object
@@ -366,4 +366,6 @@ int main()
 #endif
     test_no_result<PMD(ND&)>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
index 55fef6a406e..4c020d3da77 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
@@ -55,7 +55,7 @@ void test_result_of_imp()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef char F::*PMD;
@@ -168,4 +168,6 @@ int main()
     test_result_of_imp<int (F::* (std::unique_ptr<const F> ))       () const, int>();
     }
     test_result_of_imp<decltype(&wat::foo)(wat), void>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp
index 2946e17f55d..7e90c3df9c6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp
@@ -22,7 +22,7 @@ void test_type_identity()
     static_assert((std::is_same<         std::type_identity_t<T>,     T>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test_type_identity<void>();
     test_type_identity<int>();
@@ -36,4 +36,6 @@ int main()
     test_type_identity<int(int) volatile>();
     test_type_identity<int(int)  &>();
     test_type_identity<int(int) &&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp
index ed1bdc44c69..be1c739ee82 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp
@@ -27,7 +27,7 @@ enum E { V = INT_MIN };
 enum F { W = UINT_MAX };
 #endif // TEST_UNSIGNED_UNDERLYING_TYPE
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::underlying_type<E>::type, int>::value),
                   "E has the wrong underlying type");
@@ -52,4 +52,6 @@ int main()
     static_assert((std::is_same<std::underlying_type_t<G>, char>::value), "");
 #endif // TEST_STD_VER > 11
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp
index ec4e270be47..22c0b79d6f2 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp
@@ -45,7 +45,7 @@ void test_function1()
 
 struct Foo {};
 
-int main()
+int main(int, char**)
 {
     test_add_pointer<void, void*>();
     test_add_pointer<int, int*>();
@@ -76,4 +76,6 @@ int main()
     test_function0<void (Foo::*)() const &>();
     test_function0<void (Foo::*)() const &&>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp
index 1f62b141251..ba7cceb2968 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp
@@ -22,7 +22,7 @@ void test_remove_pointer()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_pointer<void, void>();
     test_remove_pointer<int, int>();
@@ -40,4 +40,6 @@ int main()
     test_remove_pointer<int(*)[3], int[3]>();
     test_remove_pointer<int*&, int*&>();
     test_remove_pointer<const int*&, const int*&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp
index 68d8aef35e1..dadcafca6b0 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp
@@ -44,7 +44,7 @@ void test_function1()
 
 struct Foo {};
 
-int main()
+int main(int, char**)
 {
     test_add_lvalue_reference<void, void>();
     test_add_lvalue_reference<int, int&>();
@@ -75,4 +75,6 @@ int main()
     test_function0<void (Foo::*)() const &>();
     test_function0<void (Foo::*)() const &&>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp
index c13a6236631..34c6cd3dd6d 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp
@@ -46,7 +46,7 @@ void test_function1()
 
 struct Foo {};
 
-int main()
+int main(int, char**)
 {
     test_add_rvalue_reference<void, void>();
     test_add_rvalue_reference<int, int&&>();
@@ -73,4 +73,6 @@ int main()
     test_function0<void (Foo::*)() &&>();
     test_function0<void (Foo::*)() const &>();
     test_function0<void (Foo::*)() const &&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp
index 1cecd51e28d..5612ba678ab 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp
@@ -22,7 +22,7 @@ void test_remove_reference()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_reference<void, void>();
     test_remove_reference<int, int>();
@@ -43,4 +43,6 @@ int main()
     test_remove_reference<int*&&, int*>();
     test_remove_reference<const int*&&, const int*>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp
index b962782d03d..fa6ce8e3e4d 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp
@@ -42,7 +42,7 @@ void test_make_signed()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_make_signed< signed char, signed char >();
     test_make_signed< unsigned char, signed char >();
@@ -66,4 +66,6 @@ int main()
     test_make_signed< HugeEnum, __int128_t >();
 # endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp
index 606fdf426a9..cf5404f8c90 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp
@@ -42,7 +42,7 @@ void test_make_unsigned()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_make_unsigned<signed char, unsigned char> ();
     test_make_unsigned<unsigned char, unsigned char> ();
@@ -67,4 +67,6 @@ int main()
     test_make_unsigned<HugeEnum, __uint128_t>();
 # endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp b/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp
index 65ba3019261..52924b357b8 100644
--- a/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
     static_assert(std::is_enum<std::endian>::value, "");
 
 // Check that E is a scoped enum by checking for conversions.
@@ -43,4 +43,6 @@ int main() {
 
     assert ((c[0] == 1) == (std::endian::native == std::endian::big));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp
index 903098415be..43cc5bfcefc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp
@@ -39,7 +39,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_alignment_of<int&, 4>();
     test_alignment_of<Class, 1>();
@@ -57,4 +57,6 @@ int main()
     test_alignment_of<bool, 1>();
 #endif
     test_alignment_of<unsigned, 4>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp
index bfd36533ebb..927ce1373cc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp
@@ -50,7 +50,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_extent<void, 0>();
     test_extent<int&, 0>();
@@ -70,4 +70,6 @@ int main()
     test_extent1<int[2], 0>();
     test_extent1<int[2][4], 4>();
     test_extent1<int[][4], 4>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp
index 74a3637a475..6c2eecb86db 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp
@@ -35,7 +35,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_rank<void, 0>();
     test_rank<int&, 0>();
@@ -50,4 +50,6 @@ int main()
     test_rank<char[3], 1>();
     test_rank<char[][3], 2>();
     test_rank<char[][4][3], 3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
index af46f4726fc..652eddaa88a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
@@ -45,7 +45,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     static_assert( std::is_same<void, std::void_t<>>::value, "");
 
@@ -64,4 +64,6 @@ int main()
     test2<void *, int&>();
 
     static_assert( std::is_same<void, std::void_t<int, double const &, Class, volatile int[], void>>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp
index 25b8d715aed..90514eaaebf 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp
@@ -27,9 +27,11 @@
 # endif
 #endif
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_void_t)
   static_assert(std::is_same_v<std::void_t<int>, void>, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp
index 1e2dc42ae21..9f3d8f558d1 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp
@@ -48,7 +48,7 @@ typedef const char const_array[3];
 typedef char incomplete_array[];
 struct Incomplete;
 
-int main()
+int main(int, char**)
 {
     test_array<array>();
     test_array<const_array>();
@@ -57,4 +57,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_array<Incomplete>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp
index 93bf9efb42f..3dd696932bc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp
@@ -49,11 +49,13 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_class<Class>();
     test_class<incomplete_type>();
 
 //  LWG#2582
     static_assert( std::is_class<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp
index 95f71b68a2e..5fa8499303c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp
@@ -46,10 +46,12 @@ void test_enum()
 enum Enum {zero, one};
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_enum<Enum>();
 
 //  LWG#2582
     static_assert(!std::is_enum<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp
index c4cf7153b44..1f7556c7a01 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp
@@ -45,7 +45,7 @@ void test_floating_point()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_floating_point<float>();
     test_floating_point<double>();
@@ -53,4 +53,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_floating_point<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp
index 19ad3e92b84..d7453be469c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp
@@ -66,7 +66,7 @@ void test()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     TEST_REGULAR( void () );
     TEST_REGULAR( void (int) );
@@ -89,4 +89,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_function<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp
index 74977e4b160..df66316b9c8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp
@@ -45,7 +45,7 @@ void test_integral()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_integral<bool>();
     test_integral<char>();
@@ -67,4 +67,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_integral<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp
index 8611daa15f1..3205819911c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_array<char[3]>();
     test_is_array<char[]>();
@@ -90,4 +90,6 @@ int main()
     test_is_not_array<bit_zero>();
     test_is_not_array<NotEmpty>();
     test_is_not_array<incomplete_type>();  //  LWG#2582
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp
index 6eda248f7c5..def798b779b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_class<Empty>();
     test_is_class<bit_zero>();
@@ -96,4 +96,6 @@ int main()
     test_is_not_class<Enum>();
     test_is_not_class<Union>();
     test_is_not_class<FunctionPtr>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp
index 0261581f6bf..7d4b67fd872 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_enum<Enum>();
 
@@ -91,4 +91,6 @@ int main()
     test_is_not_enum<Abstract>();
     test_is_not_enum<FunctionPtr>();
     test_is_not_enum<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp
index 78e581a0c4f..e628451dc7d 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_floating_point<float>();
     test_is_floating_point<double>();
@@ -99,4 +99,6 @@ int main()
     test_is_not_floating_point<Enum>();
     test_is_not_floating_point<FunctionPtr>();
     test_is_not_floating_point<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp
index 0f2304fe7cd..b582499cb8b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp
@@ -74,7 +74,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_function<void(void)>();
     test_is_function<int(int)>();
@@ -105,4 +105,6 @@ int main()
   test_is_function<void() noexcept>();
   test_is_function<void() const && noexcept>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp
index ede74445e28..216df3b5611 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp
@@ -71,7 +71,7 @@ struct incomplete_type;
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_integral<short>();
     test_is_integral<unsigned short>();
@@ -105,4 +105,6 @@ int main()
     test_is_not_integral<NotEmpty>();
     test_is_not_integral<Abstract>();
     test_is_not_integral<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp
index fe045a29735..ed32cd9b999 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp
@@ -72,7 +72,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_lvalue_reference<int&>();
 
@@ -93,4 +93,6 @@ int main()
     test_is_not_lvalue_reference<NotEmpty>();
     test_is_not_lvalue_reference<Abstract>();
     test_is_not_lvalue_reference<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp
index 7e20b58fc01..95a8b558578 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp
@@ -71,7 +71,7 @@ struct incomplete_type;
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_member_object_pointer<int Abstract::*>();
     test_is_member_object_pointer<double NotEmpty::*>();
@@ -95,4 +95,6 @@ int main()
     test_is_not_member_object_pointer<NotEmpty>();
     test_is_not_member_object_pointer<Abstract>();
     test_is_not_member_object_pointer<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp
index 0a1b95354f5..cf46c7261db 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp
@@ -71,7 +71,7 @@ struct incomplete_type;
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_member_pointer<int Abstract::*>();
     test_is_member_pointer<double NotEmpty::*>();
@@ -102,4 +102,6 @@ int main()
   test_is_member_pointer<int (Empty::*)(int, long, long) const noexcept>();
   test_is_member_pointer<int (Empty::*)() & noexcept>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp
index 762c21406d3..7ad765d8bbd 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp
@@ -72,7 +72,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_null_pointer<std::nullptr_t>();
 
@@ -93,4 +93,6 @@ int main()
     test_is_not_null_pointer<NotEmpty>();
     test_is_not_null_pointer<Abstract>();
     test_is_not_null_pointer<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp
index 9fa33b93c53..18609b812ea 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_pointer<void*>();
     test_is_pointer<int*>();
@@ -92,4 +92,6 @@ int main()
     test_is_not_pointer<NotEmpty>();
     test_is_not_pointer<Abstract>();
     test_is_not_pointer<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp
index 92e86713cc8..d17ed5feeff 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp
@@ -72,7 +72,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_rvalue_reference<int&&>();
 
@@ -93,4 +93,6 @@ int main()
     test_is_not_rvalue_reference<NotEmpty>();
     test_is_not_rvalue_reference<Abstract>();
     test_is_not_rvalue_reference<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp
index 0fc3c4361fe..a86147a9acd 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_union<Union>();
 
@@ -91,4 +91,6 @@ int main()
     test_is_not_union<NotEmpty>();
     test_is_not_union<Abstract>();
     test_is_not_union<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp
index 0bfeaddee83..ccbca975398 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_void<void>();
 
@@ -90,4 +90,6 @@ int main()
     test_is_not_void<Enum>();
     test_is_not_void<FunctionPtr>();
     test_is_not_void<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp
index b4f010749e8..1c431edfa5f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp
@@ -37,11 +37,13 @@ void test_lvalue_ref()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_lvalue_ref<int&>();
     test_lvalue_ref<const int&>();
 
 //  LWG#2582
     static_assert(!std::is_lvalue_reference<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp
index 345195e0e36..fdbfd903940 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp
@@ -52,7 +52,7 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
   test_member_function_pointer<void (Class::*)()>();
   test_member_function_pointer<void (Class::*)(int)>();
@@ -225,4 +225,6 @@ int main()
 
 //  LWG#2582
   static_assert(!std::is_member_function_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp
index 672a90a6f76..916c580d591 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp
@@ -51,7 +51,7 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_member_function_pointer<void (Class::*)()>();
     test_member_function_pointer<void (Class::*)(int)>();
@@ -79,4 +79,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_member_function_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp
index 2f77553fd58..b22e59e379d 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp
@@ -49,10 +49,12 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_member_object_pointer<int Class::*>();
 
 //  LWG#2582
     static_assert(!std::is_member_object_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp
index 759eee6681a..993b32fdf01 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp
@@ -46,13 +46,16 @@ void test_nullptr()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_nullptr<std::nullptr_t>();
 
 //  LWG#2582
     static_assert(!std::is_null_pointer<incomplete_type>::value, "");
+    return 0;
 }
 #else
-int main() {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp
index 68964f52616..68f4186db56 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp
@@ -46,7 +46,7 @@ void test_pointer()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_pointer<void*>();
     test_pointer<int*>();
@@ -55,4 +55,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp
index cf0b246c6a1..e40a2a01443 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp
@@ -38,11 +38,13 @@ void test_rvalue_ref()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_rvalue_ref<int&&>();
     test_rvalue_ref<const int&&>();
 
 //  LWG#2582
     static_assert(!std::is_rvalue_reference<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp
index 683eed65a28..a840f5bb295 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp
@@ -51,10 +51,12 @@ union Union
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_union<Union>();
 
 //  LWG#2582
     static_assert(!std::is_union<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp
index 047de20045b..d9defa528be 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp
@@ -45,10 +45,12 @@ void test_void()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_void<void>();
 
 //  LWG#2582
     static_assert(!std::is_void<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp
index b0ced4a9ce4..487e14446c3 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp
@@ -39,10 +39,12 @@ typedef char incomplete_array[];
 
 class incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_array<array>();
     test_array<const_array>();
     test_array<incomplete_array>();
     test_array<incomplete_type[]>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp
index bff535c9ade..bc072198f2e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp
@@ -39,8 +39,10 @@ class Class
 
 class incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_class<Class>();
     test_class<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp
index 33807bc4d07..71c74f2ba04 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp
@@ -35,7 +35,9 @@ void test_enum()
 
 enum Enum {zero, one};
 
-int main()
+int main(int, char**)
 {
     test_enum<Enum>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp
index 1a1eaee321c..957473c2a91 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp
@@ -33,9 +33,11 @@ void test_floating_point()
     test_floating_point_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_floating_point<float>();
     test_floating_point<double>();
     test_floating_point<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp
index 193cf688fe2..c27b1237ebf 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp
@@ -33,10 +33,12 @@ void test_function()
     test_function_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_function<void ()>();
     test_function<void (int)>();
     test_function<int (double)>();
     test_function<int (double, char)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp
index d349b75f7be..cac606a516e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp
@@ -33,7 +33,7 @@ void test_integral()
     test_integral_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_integral<bool>();
     test_integral<char>();
@@ -52,4 +52,6 @@ int main()
     test_integral<__int128_t>();
     test_integral<__uint128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp
index ff0ff7a34c8..683e885e288 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_arithmetic<short>();
     test_is_arithmetic<unsigned short>();
@@ -103,4 +103,6 @@ int main()
     test_is_not_arithmetic<bit_zero>();
     test_is_not_arithmetic<NotEmpty>();
     test_is_not_arithmetic<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp
index a0d03dd6e51..4d789066d6e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_compound<char[3]>();
     test_is_compound<char[]>();
@@ -94,4 +94,6 @@ int main()
     test_is_not_compound<void>();
     test_is_not_compound<int>();
     test_is_not_compound<double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp
index 343b1291a0f..b1a38360297 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_fundamental<std::nullptr_t>();
     test_is_fundamental<void>();
@@ -111,4 +111,6 @@ int main()
     test_is_not_fundamental<Enum>();
     test_is_not_fundamental<NotEmpty>();
     test_is_not_fundamental<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp
index e5486f73e9e..82f0ae9aa47 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
 //  Arithmetic types (3.9.1), enumeration types, pointer types, pointer to member types (3.9.2),
 //    std::nullptr_t, and cv-qualified versions of these types (3.9.3)
@@ -101,4 +101,6 @@ int main()
     test_is_not_member_pointer<int(int)>();
     test_is_not_member_pointer<Enum>();
     test_is_not_member_pointer<FunctionPtr>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp
index 8ec4a6d0fd9..8a6f6d84cfc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
 // An object type is a (possibly cv-qualified) type that is not a function type,
 // not a reference type, and not a void type.
@@ -99,4 +99,6 @@ int main()
     test_is_not_object<int&>();
     test_is_not_object<int&&>();
     test_is_not_object<int(int)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp
index a511daf3522..bb8a2d62ca9 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_reference<int&>();
 #if TEST_STD_VER >= 11
@@ -100,4 +100,6 @@ int main()
     test_is_not_reference<int Empty::*>();
     test_is_not_reference<void (Empty::*)(int)>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp
index c20f1e8ef5a..804c6848eab 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
 //  Arithmetic types (3.9.1), enumeration types, pointer types, pointer to member types (3.9.2),
 //    std::nullptr_t, and cv-qualified versions of these types (3.9.3)
@@ -110,4 +110,6 @@ int main()
     test_is_not_scalar<NotEmpty>();
     test_is_not_scalar<Abstract>();
     test_is_not_scalar<int(int)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp
index 0ce0423f646..44027dadb26 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp
@@ -24,8 +24,10 @@ void test_lvalue_ref()
     static_assert(!std::is_member_pointer<T>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test_lvalue_ref<int&>();
     test_lvalue_ref<const int&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp
index cc75ef9666a..fda2e81818a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp
@@ -37,9 +37,11 @@ class Class
 {
 };
 
-int main()
+int main(int, char**)
 {
     test_member_function_pointer<void (Class::*)()>();
     test_member_function_pointer<void (Class::*)(int)>();
     test_member_function_pointer<void (Class::*)(int, char)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp
index ea130274211..3e8117b6a01 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp
@@ -37,7 +37,9 @@ class Class
 {
 };
 
-int main()
+int main(int, char**)
 {
     test_member_object_pointer<int Class::*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp
index 61ae96e5b35..f5677b95b67 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp
@@ -33,10 +33,12 @@ void test_pointer()
     test_pointer_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_pointer<void*>();
     test_pointer<int*>();
     test_pointer<const int*>();
     test_pointer<void (*)(int)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp
index 63180a00807..341b9462692 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp
@@ -26,8 +26,10 @@ void test_rvalue_ref()
     static_assert(!std::is_member_pointer<T>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test_rvalue_ref<int&&>();
     test_rvalue_ref<const int&&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp
index d30354d1a25..fb48a70f35f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp
@@ -39,7 +39,9 @@ union Union
     double __;
 };
 
-int main()
+int main(int, char**)
 {
     test_union<Union>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp
index 3559d7b8311..657f72774f4 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp
@@ -33,7 +33,9 @@ void test_void()
     test_void_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_void<void>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp
index d778526b540..e6f70123b2c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp
@@ -80,7 +80,7 @@ struct B
 };
 
 
-int main()
+int main(int, char**)
 {
     test_has_not_has_unique_object_representations<void>();
     test_has_not_has_unique_object_representations<Empty>();
@@ -102,4 +102,6 @@ int main()
     test_has_unique_object_representations<char[3]>();
     test_has_unique_object_representations<char[]>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp
index 9ee9bf163ba..57c1027c3ba 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp
@@ -70,7 +70,7 @@ struct A
     ~A();
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_virtual_destructor<void>();
     test_has_not_virtual_destructor<A>();
@@ -87,4 +87,6 @@ int main()
 
     test_has_virtual_destructor<Abstract>();
     test_has_virtual_destructor<NotEmpty>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp
index cbc0317900d..ee6a12e4bd8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp
@@ -72,7 +72,7 @@ struct AbstractTemplate {
 template <>
 struct AbstractTemplate<double> {};
 
-int main()
+int main(int, char**)
 {
     test_is_not_abstract<void>();
     test_is_not_abstract<int&>();
@@ -90,4 +90,6 @@ int main()
     test_is_abstract<Abstract>();
     test_is_abstract<AbstractTemplate<int> >();
     test_is_not_abstract<AbstractTemplate<double> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp
index a8f19fd100e..843231f4605 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp
@@ -56,7 +56,7 @@ private:
 struct Union { int x; void* y; };
 
 
-int main ()
+int main(int, char**)
 {
   {
     test_false<void>();
@@ -75,4 +75,6 @@ int main ()
     test_true<Aggregate[42][101]>();
     test_true<Union>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
index eb98ddb547b..8e5e2cc6e04 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
@@ -58,7 +58,7 @@ struct E
 template <typename T>
 struct X { T t; };
 
-int main()
+int main(int, char**)
 {
     test_is_assignable<int&, int&> ();
     test_is_assignable<int&, int> ();
@@ -79,4 +79,6 @@ int main()
 
 //  pointer to incomplete template type
     test_is_assignable<X<D>*&, X<D>*> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp
index fdbdfbd596c..0af73cf7e0c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp
@@ -30,7 +30,7 @@ void test_is_const()
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_const<void>();
     test_is_const<int>();
@@ -44,4 +44,6 @@ int main()
 
     static_assert(!std::is_const<int&>::value, "");
     static_assert(!std::is_const<const int&>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
index f78319aff8d..a5b723c0e59 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
@@ -147,7 +147,7 @@ static constexpr bool clang_disallows_valid_static_cast_bug =
 #endif
 
 
-int main()
+int main(int, char**)
 {
     typedef Base B;
     typedef Derived D;
@@ -301,4 +301,6 @@ int main()
     test_is_not_constructible<void() &&> ();
 #endif
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp
index 24719bfb89b..3f10907a4aa 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp
@@ -63,7 +63,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_copy_assignable<int> ();
     test_is_copy_assignable<int&> ();
@@ -81,4 +81,6 @@ int main()
 #endif
     test_is_not_copy_assignable<void> ();
     test_is_not_copy_assignable<C> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp
index 457270a8925..f64c40e862b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp
@@ -70,7 +70,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_copy_constructible<A>();
     test_is_copy_constructible<int&>();
@@ -91,4 +91,6 @@ int main()
 #if TEST_STD_VER >= 11
     test_is_not_copy_constructible<B>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp
index aef79f7fab9..ce2ec95618e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp
@@ -81,7 +81,7 @@ class B
     B();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_default_constructible<A>();
     test_is_default_constructible<Union>();
@@ -122,4 +122,6 @@ int main()
     test_is_not_default_constructible<void() &&> ();
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp
index 8722b78fe43..1a32efa4272 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp
@@ -97,7 +97,7 @@ struct DeletedVirtualPrivateDestructor   { private:   virtual ~DeletedVirtualPri
 #endif
 
 
-int main()
+int main(int, char**)
 {
     test_is_destructible<A>();
     test_is_destructible<int&>();
@@ -142,4 +142,6 @@ int main()
     test_is_not_destructible<NotEmpty>();
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp
index 6dafb55a387..850af8b7a75 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp
@@ -78,7 +78,7 @@ struct bit_one
     int :  1;
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_empty<void>();
     test_is_not_empty<int&>();
@@ -100,4 +100,6 @@ int main()
     test_is_empty<EmptyBase>();
     test_is_empty<StaticMember>();
     test_is_empty<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp
index 61aed970ec3..4cded0f928e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp
@@ -48,7 +48,7 @@ void test_is_not_final()
 #endif
 }
 
-int main ()
+int main(int, char**)
 {
     test_is_not_final<int>();
     test_is_not_final<int*>();
@@ -58,4 +58,6 @@ int main ()
     test_is_not_final<U1*>();
     test_is_final    <U2>();
     test_is_not_final<U2*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp
index 80bb49509b9..b86ff5a8546 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp
@@ -69,7 +69,7 @@ enum Enum {zero, one};
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     test_is_literal_type<std::nullptr_t>();
@@ -101,4 +101,6 @@ int main()
 
     test_is_not_literal_type<NotEmpty>();
     test_is_not_literal_type<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp
index edf825dd716..5a330c6d34b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp
@@ -53,7 +53,7 @@ struct A
     A();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_move_assignable<int> ();
     test_is_move_assignable<A> ();
@@ -68,4 +68,6 @@ int main()
     test_is_not_move_assignable<int[3]> ();
 #endif
     test_is_not_move_assignable<void> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp
index 3052d3925d7..06ca5c4630c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp
@@ -66,7 +66,7 @@ struct B
 #endif
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_move_constructible<char[3]>();
     test_is_not_move_constructible<char[]>();
@@ -84,4 +84,6 @@ int main()
     test_is_move_constructible<NotEmpty>();
     test_is_move_constructible<bit_zero>();
     test_is_move_constructible<B>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp
index c0a22e3b7a0..be1f016a4eb 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp
@@ -45,7 +45,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_nothrow_assignable<int&, int&> ();
     test_is_nothrow_assignable<int&, int> ();
@@ -58,4 +58,6 @@ int main()
     test_is_not_nothrow_assignable<B, A> ();
     test_is_not_nothrow_assignable<A, B> ();
     test_is_not_nothrow_assignable<C, C&> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp
index e9c256acaff..0d171261a59 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp
@@ -97,7 +97,7 @@ struct Tuple {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     test_is_nothrow_constructible<int> ();
     test_is_nothrow_constructible<int, const int&> ();
@@ -114,4 +114,6 @@ int main()
     static_assert(!std::is_constructible<Tuple&, Empty>::value, "");
     test_is_not_nothrow_constructible<Tuple &, Empty> (); // See bug #19616.
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp
index a3d2611c93a..64895adf45c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp
@@ -52,7 +52,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_nothrow_assign<int&>();
     test_has_nothrow_assign<Union>();
@@ -68,4 +68,6 @@ int main()
     test_has_not_nothrow_assign<void>();
     test_has_not_nothrow_assign<A>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp
index 4caaeca259d..6b1708839ae 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp
@@ -55,7 +55,7 @@ struct A
     A(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_nothrow_copy_constructor<void>();
     test_has_not_nothrow_copy_constructor<A>();
@@ -68,4 +68,6 @@ int main()
     test_is_nothrow_copy_constructible<int*>();
     test_is_nothrow_copy_constructible<const int*>();
     test_is_nothrow_copy_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp
index 6e443b303ce..c30facc516b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp
@@ -67,7 +67,7 @@ struct DThrows
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     test_has_not_nothrow_default_constructor<void>();
     test_has_not_nothrow_default_constructor<int&>();
@@ -84,4 +84,6 @@ int main()
     test_is_nothrow_default_constructible<const int*>();
     test_is_nothrow_default_constructible<char[3]>();
     test_is_nothrow_default_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp
index f58a93ce28a..817d696d11f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp
@@ -79,7 +79,7 @@ class Abstract
 };
 
 
-int main()
+int main(int, char**)
 {
     test_is_not_nothrow_destructible<void>();
     test_is_not_nothrow_destructible<char[]>();
@@ -110,4 +110,6 @@ int main()
     test_is_not_nothrow_destructible<PureProtectedDestructor>();
     test_is_not_nothrow_destructible<PurePrivateDestructor>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp
index cb446ef0123..4bcbabbcc4a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp
@@ -52,7 +52,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_nothrow_assign<int&>();
     test_has_nothrow_assign<Union>();
@@ -66,4 +66,6 @@ int main()
 
     test_has_not_nothrow_assign<void>();
     test_has_not_nothrow_assign<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp
index ce002e8204c..ab9e0c6bb4f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp
@@ -55,7 +55,7 @@ struct A
     A(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_nothrow_move_constructor<void>();
     test_has_not_nothrow_move_constructor<A>();
@@ -68,4 +68,6 @@ int main()
     test_is_nothrow_move_constructible<int*>();
     test_is_nothrow_move_constructible<const int*>();
     test_is_nothrow_move_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp
index c90f938c5dc..f554199c606 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp
@@ -46,7 +46,7 @@ struct ThrowingMove {
 
 } // namespace MyNS
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -79,4 +79,6 @@ int main()
         static_assert(std::is_nothrow_swappable_v<int>, "");
         static_assert(!std::is_nothrow_swappable_v<void>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp
index 2121f75b092..fb4beac17c9 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp
@@ -45,7 +45,7 @@ void swap(M&&, M&&) noexcept {}
 
 } // namespace MyNS
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -77,4 +77,6 @@ int main()
         static_assert(std::is_nothrow_swappable_with_v<int&, int&>, "");
         static_assert(!std::is_nothrow_swappable_with_v<int&&, int&&>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
index f0dac244c9b..87fe6ebbee8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
@@ -49,7 +49,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_pod<void>();
     test_is_not_pod<int&>();
@@ -61,4 +61,6 @@ int main()
     test_is_pod<const int*>();
     test_is_pod<char[3]>();
     test_is_pod<char[]>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp
index feb8f270e52..8829fea6bd7 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp
@@ -72,7 +72,7 @@ class Final {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     test_is_not_polymorphic<void>();
     test_is_not_polymorphic<int&>();
@@ -91,4 +91,6 @@ int main()
 
     test_is_polymorphic<NotEmpty>();
     test_is_polymorphic<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp
index 5e9042c797e..4936cc788e2 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp
@@ -51,7 +51,7 @@ public:
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_not_signed<void>();
     test_is_not_signed<int&>();
@@ -71,4 +71,6 @@ int main()
     test_is_signed<__int128_t>();
     test_is_not_signed<__uint128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp
index 10f23cca988..fb096c89ad0 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp
@@ -50,11 +50,13 @@ struct pair
     T2 second;
 };
 
-int main()
+int main(int, char**)
 {
     test_is_standard_layout<int> ();
     test_is_standard_layout<int[3]> ();
     test_is_standard_layout<pair<int, double> > ();
 
     test_is_not_standard_layout<int&> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
index 3e0980bd5cf..5768a954d64 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
@@ -63,7 +63,7 @@ void swap(T&, T&) {}
 
 } // end namespace MyNS2
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -94,4 +94,6 @@ int main()
         static_assert(std::is_swappable_v<int>, "");
         static_assert(!std::is_swappable_v<M>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp
index 5d21f3699b3..5931e7ce7f3 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     // Use a builtin type so we don't get ADL lookup.
     typedef double T[17][29];
@@ -39,4 +39,6 @@ int main()
        std::iter_swap(t1, t2);
        std::swap_ranges(t1, t1 + 17, t2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp
index f11f9333860..cd65d14efc0 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp
@@ -45,7 +45,7 @@ void swap(M&&, M&&) {}
 
 } // namespace MyNS
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -74,4 +74,6 @@ int main()
         static_assert(std::is_swappable_with_v<int&, int&>, "");
         static_assert(!std::is_swappable_with_v<D&, C&>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp
index 4350f12997f..8bb1b7c9b09 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp
@@ -51,7 +51,7 @@ public:
     B();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivial<int> ();
     test_is_trivial<A> ();
@@ -59,4 +59,6 @@ int main()
     test_is_not_trivial<int&> ();
     test_is_not_trivial<volatile int&> ();
     test_is_not_trivial<B> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp
index a85f57a5e00..124480c0755 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp
@@ -47,7 +47,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivially_assignable<int&, int&> ();
     test_is_trivially_assignable<int&, int> ();
@@ -58,4 +58,6 @@ int main()
     test_is_not_trivially_assignable<B, A> ();
     test_is_not_trivially_assignable<A, B> ();
     test_is_not_trivially_assignable<C&, C&> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp
index 78ae8cfa99f..42d54bd7e25 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp
@@ -65,7 +65,7 @@ struct A
     A(int, double);
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivially_constructible<int> ();
     test_is_trivially_constructible<int, const int&> ();
@@ -73,4 +73,6 @@ int main()
     test_is_not_trivially_constructible<A, int> ();
     test_is_not_trivially_constructible<A, int, double> ();
     test_is_not_trivially_constructible<A> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp
index 853c8aa32b5..91fbf69f4f2 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp
@@ -59,7 +59,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_trivially_copy_assignable<int&>();
     test_has_trivially_copy_assignable<Union>();
@@ -76,4 +76,6 @@ int main()
     test_has_not_trivially_copy_assignable<Abstract>();
     test_has_not_trivially_copy_assignable<const Empty>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp
index decd7ffeafa..5744d2ca0e8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp
@@ -65,7 +65,7 @@ struct A
     A(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_trivial_copy_constructor<void>();
     test_has_not_trivial_copy_constructor<A>();
@@ -80,4 +80,6 @@ int main()
     test_is_trivially_copy_constructible<int*>();
     test_is_trivially_copy_constructible<const int*>();
     test_is_trivially_copy_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp
index 073ea681d6e..51ac0803e66 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp
@@ -65,7 +65,7 @@ public:
     C();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivially_copyable<int> ();
     test_is_trivially_copyable<const int> ();
@@ -76,4 +76,6 @@ int main()
     test_is_not_trivially_copyable<int&> ();
     test_is_not_trivially_copyable<const A&> ();
     test_is_not_trivially_copyable<B> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp
index 2f70ba606a2..03ac030a3d7 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp
@@ -69,7 +69,7 @@ struct A
     A();
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_trivial_default_constructor<void>();
     test_has_not_trivial_default_constructor<int&>();
@@ -85,4 +85,6 @@ int main()
     test_is_trivially_default_constructible<const int*>();
     test_is_trivially_default_constructible<char[3]>();
     test_is_trivially_default_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp
index 37ea513fcf2..e79e4926b0d 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp
@@ -87,7 +87,7 @@ struct A
     ~A();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_trivially_destructible<void>();
     test_is_not_trivially_destructible<A>();
@@ -115,4 +115,6 @@ int main()
     test_is_not_trivially_destructible<PureProtectedDestructor>();
     test_is_not_trivially_destructible<PurePrivateDestructor>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp
index c4aa7b7dced..0a91efdf089 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp
@@ -59,7 +59,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_trivial_assign<int&>();
     test_has_trivial_assign<Union>();
@@ -76,4 +76,6 @@ int main()
     test_has_not_trivial_assign<Abstract>();
     test_has_not_trivial_assign<const Empty>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp
index 6f47ed6fd4d..78c10a1320a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp
@@ -75,7 +75,7 @@ struct MoveOnly2
 
 #endif
 
-int main()
+int main(int, char**)
 {
     test_has_not_trivial_move_constructor<void>();
     test_has_not_trivial_move_constructor<A>();
@@ -94,4 +94,6 @@ int main()
     static_assert(!std::is_trivially_move_constructible<MoveOnly1>::value, "");
     static_assert( std::is_trivially_move_constructible<MoveOnly2>::value, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp
index 86e5611c7b2..bc70a43b9bd 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp
@@ -51,7 +51,7 @@ public:
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_not_unsigned<void>();
     test_is_not_unsigned<int&>();
@@ -71,4 +71,6 @@ int main()
     test_is_unsigned<__uint128_t>();
     test_is_not_unsigned<__int128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp
index 28cb29f3bd9..cb0fc3c6ea8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp
@@ -30,7 +30,7 @@ void test_is_volatile()
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_volatile<void>();
     test_is_volatile<int>();
@@ -44,4 +44,6 @@ int main()
 
     static_assert(!std::is_volatile<int&>::value, "");
     static_assert(!std::is_volatile<volatile int&>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp b/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp
index cfae639636a..9bcfa8e4656 100644
--- a/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp
@@ -23,8 +23,10 @@
 #include <optional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     using std::bad_optional_access;
     bad_optional_access ex;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp b/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp
index 80f2372e456..ac7be93f709 100644
--- a/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp
@@ -23,10 +23,12 @@
 #include <optional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     using std::bad_optional_access;
 
     static_assert(std::is_base_of<std::exception, bad_optional_access>::value, "");
     static_assert(std::is_convertible<bad_optional_access*, std::exception*>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
index dbf8a0564b5..4f7aedbcb0f 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator==(const X& lhs, const X& rhs) {
   return lhs.i_ == rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 == 42, "");
     static_assert(!(101 == o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp
index 539e35fe065..373634f68c2 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp
@@ -24,7 +24,7 @@ struct X {
 
 constexpr bool operator>(const X& lhs, const X& rhs) { return lhs.i_ > rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 > 11, "");
     static_assert(!(42 > o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp
index c7bbbda8580..5d4839734bb 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator>=(const X& lhs, const X& rhs) {
   return lhs.i_ >= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -62,4 +62,6 @@ int main() {
     static_assert(o1 >= 42, "");
     static_assert(!(11 >= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp
index 73ed8564340..a601939c5b3 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator<=(const X& lhs, const X& rhs) {
   return lhs.i_ <= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -62,4 +62,6 @@ int main() {
     static_assert(o1 <= 42, "");
     static_assert(!(101 <= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp
index c0c111afdca..7320955908a 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp
@@ -24,7 +24,7 @@ struct X {
 
 constexpr bool operator<(const X& lhs, const X& rhs) { return lhs.i_ < rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 < 101, "");
     static_assert(!(42 < o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp
index 949a03a8c5b..0d14f1e97a9 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator!=(const X& lhs, const X& rhs) {
   return lhs.i_ != rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 != 101, "");
     static_assert(!(42 != o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp
index a842804f374..66ab089dc30 100644
--- a/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp
@@ -17,9 +17,11 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
 
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp b/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp
index 0f74557b730..aa89a51d8d4 100644
--- a/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp
@@ -30,7 +30,7 @@ struct hash<B> {
 
 }
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     const std::size_t nullopt_hash =
@@ -76,4 +76,6 @@ int main()
       test_hash_enabled_for_type<std::optional<B>>();
       test_hash_enabled_for_type<std::optional<const B>>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp
index 05413c1f14d..5894462205a 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt == o1), "");
     static_assert (noexcept(o1 == nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp
index 7bc764d01b8..59dc62fce17 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt > o1), "");
     static_assert (noexcept(o1 > nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp
index 7c77a95a150..e23e8794f44 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt >= o1), "");
     static_assert (noexcept(o1 >= nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp
index 1d3994e4a50..96f0754e40b 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp
@@ -15,7 +15,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -36,4 +36,6 @@ int main()
     static_assert (noexcept(nullopt <= o1), "");
     static_assert (noexcept(o1 <= nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp
index 3b313c946d7..872f3159a92 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt < o1), "");
     static_assert (noexcept(o1 < nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp
index 9b3c41c1c48..7eea0fa8856 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt != o1), "");
     static_assert (noexcept(o1 != nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp
index 9cbbc8bd972..2a7822ebb63 100644
--- a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp
@@ -18,7 +18,9 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     std::nullopt_t n = {};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp
index f664433cb42..c9d843e9c2a 100644
--- a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp
@@ -29,11 +29,13 @@ constexpr bool test()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_empty_v<nullopt_t>);
     static_assert(!std::is_default_constructible_v<nullopt_t>);
 
     static_assert(std::is_same_v<const nullopt_t, decltype(nullopt)>);
     static_assert(test());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp
index e40af08233a..8d2a8a00c94 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp
@@ -241,7 +241,7 @@ enum MyEnum { Zero, One, Two, Three, FortyTwo = 42 };
 
 using Fn = void(*)();
 
-int main()
+int main(int, char**)
 {
     test_sfinae();
     // Test with instrumented type
@@ -268,4 +268,6 @@ int main()
         assert(**opt == 3);
     }
     test_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp
index a9a1c07d898..6ccaafa6d6f 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp
@@ -196,7 +196,7 @@ void test_ambigious_assign() {
 }
 
 
-int main()
+int main(int, char**)
 {
     test_with_test_type();
     test_ambigious_assign();
@@ -250,4 +250,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp
index 8a4540e18e6..5900e60461e 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp
@@ -48,7 +48,7 @@ constexpr bool assign_value(optional<Tp>&& lhs) {
     return lhs.has_value() && rhs.has_value() && *lhs == *rhs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         using O = optional<int>;
@@ -102,4 +102,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
index cf09bb5ddde..c5cebc5420b 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
@@ -208,7 +208,7 @@ void test_on_test_type() {
 
 
 
-int main()
+int main(int, char**)
 {
     {
         test_on_test_type<TestTypes::TestType>();
@@ -265,4 +265,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp
index 9141bea11c9..446e9ae9668 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp
@@ -69,7 +69,7 @@ public:
 
 bool Z::dtor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         X x;
@@ -117,4 +117,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp
index 0c36da93d92..c862c5f0efd 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp
@@ -66,7 +66,7 @@ constexpr bool assign_value(optional<Tp>&& lhs) {
     return lhs.has_value() && rhs.has_value() && *lhs == Tp{101};
 }
 
-int main()
+int main(int, char**)
 {
     {
         static_assert(std::is_nothrow_move_assignable<optional<int>>::value, "");
@@ -204,4 +204,5 @@ int main()
         };
         static_assert(std::is_nothrow_move_assignable<optional<NoThrowMove>>::value, "");
     }
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp
index e6b67430fff..af582d73205 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp
@@ -22,7 +22,7 @@ using std::optional;
 using std::nullopt_t;
 using std::nullopt;
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> opt;
@@ -63,4 +63,6 @@ int main()
     assert(TT::alive == 0);
     assert(TT::destroyed == 1);
     TT::reset();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp
index d043fd1def8..cabaa070b27 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp
@@ -201,7 +201,7 @@ void test_ambigious_assign() {
 }
 
 
-int main()
+int main(int, char**)
 {
     test_with_test_type();
     test_ambigious_assign();
@@ -264,4 +264,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
index 861ab91d80f..f91cd110f96 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
@@ -153,7 +153,9 @@ void test_explicit() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
     test_implicit();
     test_explicit();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp
index 462811e5103..1a7b36a5bf3 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp
@@ -29,7 +29,7 @@
 
 using std::optional;
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -132,4 +132,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp
index 4666d6d9b7f..b28d22330a9 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp
@@ -78,7 +78,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef short U;
@@ -130,4 +130,6 @@ int main()
     }
 
     static_assert(!(std::is_constructible<optional<X>, const optional<Y>&>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp
index 844abda00ee..e6793cd4794 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp
@@ -113,7 +113,7 @@ void test_reference_extension()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<int>(3);
@@ -169,4 +169,6 @@ int main()
         constexpr std::optional<int> o2 = o1;
         static_assert( *o2 == 4, "" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
index 9439642418f..7c6ae9bcdac 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
 
@@ -42,4 +42,6 @@ int main()
 //  optional(nullopt_t)
     std::optional opt(std::nullopt);   // expected-error-re@optional:* {{static_assert failed{{.*}} "instantiation of optional with nullopt_t is ill-formed"}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
index 973b49dff19..fa2edfcdd69 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -50,4 +50,6 @@ int main()
     assert(static_cast<bool>(opt) == static_cast<bool>(source));
     assert(*opt == *source);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp
index a00fa170609..3dd38da9d57 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp
@@ -61,7 +61,7 @@ test()
     };
 }
 
-int main()
+int main(int, char**)
 {
     test_constexpr<optional<int>>();
     test_constexpr<optional<int*>>();
@@ -77,4 +77,6 @@ int main()
     test_constexpr<optional<NonLiteralTypes::NoCtors&>>();
     test_constexpr<optional<NonLiteralTypes::NoCtors&&>>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp
index 37adf8bbe06..7741e035342 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp
@@ -79,7 +79,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef X T;
@@ -117,4 +117,6 @@ int main()
         optional<U> rhs(3);
         test<T>(rhs, true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp
index ea4b7aa50da..71febba3529 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp
@@ -62,7 +62,7 @@ public:
     explicit Z(int) { TEST_THROW(6); }
 };
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> rhs;
@@ -80,4 +80,6 @@ int main()
         optional<int> rhs(3);
         test<Z>(std::move(rhs), true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp
index 5cd23bad045..db995b4a7e8 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp
@@ -58,7 +58,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         constexpr optional<int> opt(in_place, 5);
@@ -144,4 +144,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp
index f62e6a3a89e..c8c76df2567 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp
@@ -66,7 +66,7 @@ public:
         {return x.i_ == y.i_ && x.j_ == y.j_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         static_assert(!std::is_constructible<X, std::initializer_list<int>&>::value, "");
@@ -112,4 +112,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp
index 622b8e428a0..a8634b961c7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp
@@ -28,9 +28,11 @@ struct S {
     };
 
 
-int main()
+int main(int, char**)
 {
     static_assert (!std::is_trivially_move_constructible_v<S>, "" );
     constexpr std::optional<S> o1;
     constexpr std::optional<S> o2 = std::move(o1);  // not constexpr
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp
index afba631bf95..bf536ec6342 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp
@@ -151,7 +151,7 @@ void test_reference_extension()
 }
 
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<int>(3);
@@ -225,4 +225,6 @@ int main()
     constexpr std::optional<int> o2 = std::move(o1);
     static_assert( *o2 == 4, "" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp
index 850ed6ecaad..927ac19ead1 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp
@@ -61,7 +61,7 @@ test()
     };
 }
 
-int main()
+int main(int, char**)
 {
     test_constexpr<optional<int>>();
     test_constexpr<optional<int*>>();
@@ -69,4 +69,6 @@ int main()
     test_constexpr<optional<NonTrivialTypes::NoCtors>>();
     test_constexpr<optional<NonConstexprTypes::NoCtors>>();
     test<optional<NonLiteralTypes::NoCtors>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp
index fd74f9ae18c..fe4252b49c7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp
@@ -61,7 +61,7 @@ struct Z
     Z(int) { TEST_THROW(6); }
 };
 
-int main()
+int main(int, char**)
 {
     {
         optional<short> rhs;
@@ -89,4 +89,6 @@ int main()
     }
 
     static_assert(!(std::is_constructible<optional<X>, optional<Z>>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
index 5e9a216dcb9..7fd1f2fa16e 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
@@ -39,7 +39,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -157,4 +157,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp
index ca96586a139..23497bc4c47 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp
@@ -32,7 +32,7 @@ public:
 
 bool X::dtor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
         }
         assert(X::dtor_called == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp
index e766db87eb6..704606c6f75 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp
@@ -26,7 +26,7 @@ struct X
 
 bool X::dtor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> opt;
@@ -55,4 +55,6 @@ int main()
         assert(static_cast<bool>(opt) == false);
         X::dtor_called = false;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp
index 29bf20bbd08..7c008ef6209 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     {
@@ -33,4 +33,6 @@ int main()
         constexpr optional<int> opt(0);
         static_assert(opt, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
index b109346f588..368f84155db 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
@@ -43,7 +43,7 @@ test()
     return (*opt).test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
index 6663d88513f..99a60e8dd6f 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
@@ -36,7 +36,7 @@ struct Y
     int test() const {return 2;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -65,4 +65,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
index 02466d53b11..ca494c5a83d 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
@@ -36,7 +36,7 @@ struct Y
     int test() const && {return 2;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -65,4 +65,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
index 7dca9f61345..f1b2ca393af 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
@@ -43,7 +43,7 @@ test()
     return (*std::move(opt)).test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp
index 59ce4c7e8ee..560fa8894b7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     {
@@ -33,4 +33,6 @@ int main()
         constexpr optional<int> opt(0);
         static_assert(opt.has_value(), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
index ac0b9a52788..8c6c0986140 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
@@ -40,7 +40,7 @@ test()
     return opt->test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::optional<X> opt; ((void)opt);
@@ -68,4 +68,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
index fd7e683be77..b9539828a98 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
@@ -39,7 +39,7 @@ struct Z
     constexpr int test() const {return 1;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const std::optional<X> opt; ((void)opt);
@@ -72,4 +72,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp
index 04a4fcffd90..23fd85ba53f 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp
@@ -52,7 +52,7 @@ test()
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -78,4 +78,6 @@ int main()
     }
 #endif
     static_assert(test() == 7, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp
index ab6504dba9f..5e81f2fb11d 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp
@@ -23,10 +23,12 @@ struct X
     int test() {return 4;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         constexpr optional<X> opt;
         static_assert(opt.value().test() == 3, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp
index dcc9306b152..54bdc1001d9 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp
@@ -41,7 +41,7 @@ struct X
     int test() && {return 6;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp
index 5e218d80e3f..b330bb8db87 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp
@@ -41,7 +41,7 @@ struct X
     int test() && {return 6;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp
index 93ec45b0bec..8f22f1c0dc8 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp
@@ -67,7 +67,9 @@ constexpr int test()
     return 0;
 }
 
-int main()
+int main(int, char**)
 {
     static_assert(test() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp
index 0b4c7928f21..736fe791af6 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp
@@ -35,7 +35,7 @@ struct X
         {return x.i_ == y.i_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         constexpr optional<X> opt(2);
@@ -73,4 +73,6 @@ int main()
         const optional<X> opt;
         assert(opt.value_or(Y(3)) == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp
index 21f630e8c36..06206a324d4 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp
@@ -50,7 +50,7 @@ test()
     return std::move(opt).value().test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -76,4 +76,6 @@ int main()
     }
 #endif
     static_assert(test() == 7, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp
index 7d79251e241..e881a0c6286 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp
@@ -64,7 +64,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> opt1;
@@ -302,4 +302,6 @@ int main()
         assert(*opt2 == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp
index 67e1b76d7cb..531173ade8b 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp
@@ -21,7 +21,7 @@ private:
     ~X() {}
 };
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     {
@@ -46,4 +46,6 @@ int main()
     }
     // FIXME these are garbage diagnostics that Clang should not produce
     // expected-error@optional:* 0+ {{is not a base class}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp
index a315ed8ca75..28783264d71 100644
--- a/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp
@@ -52,11 +52,12 @@ struct DoTestsMetafunction {
     DoTestsMetafunction() { sink(SpecialMemberTest<TestTypes>{}...); }
 };
 
-int main() {
+int main(int, char**) {
     sink(
         ImplicitTypes::ApplyTypes<DoTestsMetafunction>{},
         ExplicitTypes::ApplyTypes<DoTestsMetafunction>{},
         NonLiteralTypes::ApplyTypes<DoTestsMetafunction>{},
         NonTrivialTypes::ApplyTypes<DoTestsMetafunction>{}
     );
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp
index 7c82e17d611..f53d86000e7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp
@@ -85,7 +85,7 @@ struct TrivialCopyNonTrivialMove {
     TrivialCopyNonTrivialMove& operator=(TrivialCopyNonTrivialMove&&) { return *this; }
 };
 
-int main() {
+int main(int, char**) {
     sink(
         ImplicitTypes::ApplyTypes<DoTestsMetafunction>{},
         ExplicitTypes::ApplyTypes<DoTestsMetafunction>{},
@@ -93,4 +93,5 @@ int main() {
         NonTrivialTypes::ApplyTypes<DoTestsMetafunction>{},
         DoTestsMetafunction<TrivialMoveNonTrivialCopy, TrivialCopyNonTrivialMove>{}
     );
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp
index cef295754ee..7c32d1857cd 100644
--- a/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp
@@ -28,10 +28,12 @@ test()
     static_assert(std::is_same<typename Opt::value_type, T>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test<optional<int>, int>();
     test<optional<const int>, const int>();
     test<optional<double>, double>();
     test<optional<const double>, const double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp
index baeb16bb6b8..4fc85157a76 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool operator==(const X& lhs, const X& rhs) {
   return lhs.i_ == rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -82,4 +82,6 @@ int main() {
     static_assert(o1 == O2(42), "");
     static_assert(!(O2(101) == o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp
index 3a88640cad9..4bc9720aa7f 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool operator>=(const X& lhs, const X& rhs) {
   return lhs.i_ >= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -79,4 +79,6 @@ int main() {
     static_assert(o1 >= O2(42), "");
     static_assert(!(O2(1) >= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp
index 7f7b24a75f6..d168cd70635 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp
@@ -23,7 +23,7 @@ struct X {
 
 constexpr bool operator>(const X& lhs, const X& rhs) { return lhs.i_ > rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -77,4 +77,6 @@ int main() {
     static_assert(o1 > O2(1), "");
     static_assert(!(O2(42) > o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp
index e9180cb3ee6..835be64f8fb 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool operator<=(const X& lhs, const X& rhs) {
   return lhs.i_ <= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -79,4 +79,6 @@ int main() {
     static_assert(o1 <= O2(42), "");
     static_assert(!(O2(101) <= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp
index 29fa36a3edb..832de4b2981 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp
@@ -23,7 +23,7 @@ struct X {
 
 constexpr bool operator<(const X& lhs, const X& rhs) { return lhs.i_ < rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -77,4 +77,6 @@ int main() {
     static_assert(o1 < O2(101), "");
     static_assert(!(O2(101) < o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp
index 9f690477e0e..ab00b7aab18 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool operator!=(const X& lhs, const X& rhs) {
   return lhs.i_ != rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -82,4 +82,6 @@ int main() {
     static_assert(o1 != O2(101), "");
     static_assert(!(O2(42) != o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp
index fef17e77277..7725289275f 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::make_optional;
@@ -55,4 +55,6 @@ int main()
         assert(**opt == 3);
         assert(s == nullptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp
index 675e9003673..d3461542b93 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp
@@ -17,7 +17,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::make_optional;
@@ -41,4 +41,6 @@ int main()
         auto opt = make_optional<std::string>(4, 'X');
         assert(*opt == "XXXX");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp
index 4a9040e50f7..40b20bed52b 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp
@@ -27,7 +27,7 @@ struct TestT {
       : x(*il.begin()), size(static_cast<int>(il.size())) {}
 };
 
-int main()
+int main(int, char**)
 {
     using std::make_optional;
     {
@@ -49,4 +49,6 @@ int main()
         auto opt = make_optional<std::string>({'a', 'b', 'c'}, std::allocator<char>{});
         assert(*opt == "abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp
index 3f37ac6e272..1a548e8cc2e 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp
@@ -109,7 +109,7 @@ void test_swap_sfinae() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_swap_sfinae();
     {
@@ -348,4 +348,6 @@ int main()
         assert(*opt2 == 2);
     }
 #endif // TEST_HAS_NO_EXCEPTIONS
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp b/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp
index aca546d6c44..b7d3b71e0d3 100644
--- a/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::in_place_t;
@@ -22,4 +22,6 @@ int main()
 
     optional<in_place_t> opt; // expected-note {{requested here}}
     // expected-error@optional:* {{"instantiation of optional with in_place_t is ill-formed"}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp
index 28904aecf12..daaad5664b6 100644
--- a/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp
@@ -13,10 +13,12 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
 
     std::initializer_list<int> list;
     (void)list;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp b/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp
index 4fe41b44518..a4abbf02779 100644
--- a/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -25,4 +25,6 @@ int main()
     optional<nullopt_t &> opt2; // expected-note 1 {{requested here}}
     optional<nullopt_t &&> opt3; // expected-note 1 {{requested here}}
     // expected-error@optional:* 4 {{instantiation of optional with nullopt_t is ill-formed}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
index d7f775eee6e..abf75631f86 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 1> R2;
     typedef std::ratio_add<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
index ae43ac9222b..c62f75a0d87 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -72,4 +72,6 @@ int main()
     typedef std::ratio_add<R1, R2>::type R;
     static_assert(R::num == 1 && R::den == 1, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
index ea96434b855..387f6290368 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 2> R2;
     typedef std::ratio_divide<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
index 0b93e1a9cea..ce7f69473bc 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -54,4 +54,6 @@ int main()
     typedef std::ratio_divide<R1, R2>::type R;
     static_assert(R::num == 630992477165LL && R::den == 127339199162436LL, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
index b884f4e2cb8..ef59bb39e41 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<2, 1> R2;
     typedef std::ratio_multiply<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
index 876158994e7..e20f2344347 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -54,4 +54,6 @@ int main()
     typedef std::ratio_multiply<R1, R2>::type R;
     static_assert(R::num == 15519594064236LL && R::den == 5177331081415LL, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
index 95e9c823908..8b00462dc48 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<-0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 1> R2;
     typedef std::ratio_subtract<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
index dbb9480475d..e3871f7a7cf 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -72,4 +72,6 @@ int main()
     typedef std::ratio_subtract<R1, R2>::type R;
     static_assert(R::num == -1 && R::den == 1, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
index 9f547cdea56..d0b1d5a17be 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, false>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
index ab6deac86d0..dfb0e8fe87e 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
index 79942fa6d0d..811706c58aa 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
index a80112ca4b8..45ba7cbf16c 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -93,4 +93,6 @@ int main()
     typedef std::ratio<641981, 1339063> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
index c5dbdedc8f6..ebb8624a85f 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, false>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
index 68e6aba35d0..5000e73d3fc 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
index bb3bb159bde..336d7d8e5b5 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
@@ -18,7 +18,7 @@ void test()
     static_assert((std::ratio<N, D>::den == eD), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<1, 1, 1, 1>();
     test<1, 10, 1, 10>();
@@ -40,4 +40,6 @@ int main()
     test<-0x7FFFFFFFFFFFFFFFLL, 127, -72624976668147841LL, 1>();
     test<0x7FFFFFFFFFFFFFFFLL, -127, -72624976668147841LL, 1>();
     test<-0x7FFFFFFFFFFFFFFFLL, -127, 72624976668147841LL, 1>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
index 1c143f659cb..0841d858dc9 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
@@ -11,7 +11,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<1, 0>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
index bf56271fbbe..f8bebc8624d 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
@@ -12,7 +12,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<0x8000000000000000ULL, 1>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
index 6e44427f841..78310c6a245 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
@@ -12,7 +12,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<1, 0x8000000000000000ULL>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/typedefs.pass.cpp b/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
index 3f54f555a89..8e24ff9749d 100644
--- a/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::atto::num == 1 && std::atto::den == 1000000000000000000ULL, "");
     static_assert(std::femto::num == 1 && std::femto::den == 1000000000000000ULL, "");
@@ -28,4 +28,6 @@ int main()
     static_assert(std::tera::num == 1000000000000ULL && std::tera::den == 1, "");
     static_assert(std::peta::num == 1000000000000000ULL && std::peta::den == 1, "");
     static_assert(std::exa::num == 1000000000000000000ULL && std::exa::den == 1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp
index cb7a5bbf6ab..f0ca5b0ea86 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp
@@ -54,7 +54,9 @@ void test_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp
index e11ec4b4004..bc42afda309 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp
@@ -107,7 +107,7 @@ void test_sfinae() {
 }
 
 
-int main() {
+int main(int, char**) {
   {
     test_basic</*IsArray*/ false>();
     test_sfinae<false>();
@@ -116,4 +116,6 @@ int main() {
     test_basic</*IsArray*/ true>();
     test_sfinae<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp
index b89a452014d..c9ebdf63344 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp
@@ -405,7 +405,7 @@ void test_deleter_value_category() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae</*IsArray*/false>();
     test_noexcept<false>();
@@ -416,4 +416,6 @@ int main() {
     test_noexcept<true>();
     test_deleter_value_category<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp
index 0800f869fe6..ce912546533 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp
@@ -114,7 +114,9 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_sfinae();
   // FIXME: add tests
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp
index 2b9bdb8c330..d5f46935a19 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp
@@ -113,7 +113,7 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_sfinae();
   {
     std::unique_ptr<B> bptr(new B);
@@ -141,4 +141,6 @@ int main() {
   }
   assert(A::count == 0);
   assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp
index 28ea9d7b04d..ecba79dfd32 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp
@@ -32,7 +32,9 @@ void test_basic() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp
index 91349cb300e..5cd44b2f647 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp
@@ -33,7 +33,9 @@ void test_basic() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp
index e2fe7bb0dd3..577a906fb0e 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp
@@ -61,7 +61,7 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     B* p = new B;
     std::auto_ptr<B> ap(p);
@@ -93,4 +93,6 @@ int main() {
   }
 #endif
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp
index 3145c0c9f08..1bd53b9a9ca 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp
@@ -94,7 +94,7 @@ DEFINE_AND_RUN_IS_INCOMPLETE_TEST({
   doIncompleteTypeTest<IncompleteType[], Deleter<IncompleteType[]> >(0);
 })
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae<int>();
     test_basic<int>();
@@ -103,4 +103,6 @@ int main() {
     test_sfinae<int[]>();
     test_basic<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp
index f95897b9f92..7c07b2ec984 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp
@@ -159,7 +159,7 @@ void test_noexcept() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   {
     test_basic</*IsArray*/ false>();
     test_sfinae<int>();
@@ -170,4 +170,6 @@ int main() {
     test_sfinae<int[]>();
     test_noexcept<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp
index f19943a46cc..3d0bb1cd1f6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp
@@ -204,7 +204,7 @@ void test_deleter_value_category() {
 }
 
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae</*IsArray*/false>();
     test_noexcept<false>();
@@ -215,4 +215,6 @@ int main() {
     test_noexcept<true>();
     test_deleter_value_category<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp
index 010c2293a16..bcf85b11031 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp
@@ -77,6 +77,8 @@ void test_sfinae() {
 }
 
 
-int main() {
+int main(int, char**) {
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp
index d269544c331..1dcf0cf325c 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp
@@ -157,7 +157,7 @@ void test_noexcept() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae();
     test_noexcept();
@@ -244,4 +244,6 @@ int main() {
     }
     checkNoneAlive();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp
index e2694b38af8..d2453883276 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp
@@ -61,7 +61,7 @@ void test_pointer_deleter_ctor() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     // test_pointer_ctor<int>();
     test_pointer_deleter_ctor<int>();
@@ -70,4 +70,6 @@ int main() {
     test_pointer_ctor<int[]>();
     test_pointer_deleter_ctor<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp
index 8d3f94715c8..9ec7f7a4e1d 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp
@@ -93,7 +93,7 @@ DEFINE_AND_RUN_IS_INCOMPLETE_TEST({
   checkNumIncompleteTypeAlive(0);
 })
 
-int main() {
+int main(int, char**) {
   {
     test_basic<int>();
     test_sfinae<int>();
@@ -102,4 +102,6 @@ int main() {
     test_basic<int[]>();
     test_sfinae<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp
index 55a5f48b2d3..48d41fc5c0f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp
@@ -156,7 +156,7 @@ DEFINE_AND_RUN_IS_INCOMPLETE_TEST({
   checkNumIncompleteTypeAlive(0);
 })
 
-int main() {
+int main(int, char**) {
   {
     test_pointer</*IsArray*/ false>();
     test_derived();
@@ -167,4 +167,6 @@ int main() {
     test_sfinae<int[]>();
     test_sfinae_runtime();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp
index 4c5536d939c..ccb4924d024 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp
@@ -22,7 +22,9 @@ struct Deleter {
   void operator()(int* p) const { delete p; }
 };
 
-int main() {
+int main(int, char**) {
   // expected-error@+1 {{call to deleted constructor of 'std::unique_ptr<int, const Deleter &>}}
   std::unique_ptr<int, const Deleter&> s((int*)nullptr, Deleter());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
index 246af44f97f..59861effb4e 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
@@ -309,7 +309,7 @@ void test_nullptr() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   {
     test_basic</*IsArray*/ false>();
     test_nullptr<false>();
@@ -324,4 +324,6 @@ int main() {
     test_sfinae_runtime();
     test_noexcept<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp
index e7b91655899..9ef48b2e4af 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp
@@ -41,7 +41,9 @@ void test_basic() {
   assert(d.state() == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic<int>();
   test_basic<int[]>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp
index cc2a8366e9d..f080165d561 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp
@@ -49,7 +49,9 @@ void test_basic() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp
index f271a7fb47b..46569918a5f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp
@@ -102,7 +102,7 @@ void test_reset_no_arg() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   {
     test_reset_pointer</*IsArray*/ false>();
     test_reset_nullptr<false>();
@@ -113,4 +113,6 @@ int main() {
     test_reset_nullptr<true>();
     test_reset_no_arg<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp
index 98a4125ba77..7e3085a5b0f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp
@@ -17,7 +17,7 @@
 
 #include "unique_ptr_test_helper.h"
 
-int main() {
+int main(int, char**) {
   {
     std::unique_ptr<A[]> p;
     p.reset(static_cast<B*>(nullptr)); // expected-error {{no matching member function for call to 'reset'}}
@@ -26,4 +26,6 @@ int main() {
     std::unique_ptr<int[]> p;
     p.reset(static_cast<const int*>(nullptr)); // expected-error {{no matching member function for call to 'reset'}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp
index e9d43b60247..4f5a519b798 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "unique_ptr_test_helper.h"
 
-int main() {
+int main(int, char**) {
   {
     std::unique_ptr<A> p(new A);
     assert(A::count == 1);
@@ -42,4 +42,6 @@ int main() {
   }
   assert(A::count == 0);
   assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp
index 129e3ea45b1..d5e15aafe24 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp
@@ -21,4 +21,6 @@ struct A {
   void reset() { ptr_.reset(); }
 };
 
-int main() { (new A)->reset(); }
+int main(int, char**) { (new A)->reset(); 
+  return 0;
+}
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp
index 935ebab7fda..35e997e3065 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp
@@ -81,7 +81,9 @@ void test_basic() {
   assert(TT::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp
index 0fd37cbfa06..8a5566b915c 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp
@@ -15,9 +15,11 @@
 #include <memory>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<int[]> p(new int(3));
   const std::unique_ptr<int[]>& cp = p;
   TEST_IGNORE_NODISCARD (*p);  // expected-error {{indirection requires pointer operand ('std::unique_ptr<int []>' invalid)}}
   TEST_IGNORE_NODISCARD (*cp); // expected-error {{indirection requires pointer operand ('const std::unique_ptr<int []>' invalid)}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp
index 49cfccb6f85..254d88bb6cf 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp
@@ -15,7 +15,9 @@
 #include <memory>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<int> p(new int(3));
   assert(*p == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp
index ce45882a8bf..500821fb817 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp
@@ -59,7 +59,9 @@ void test_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp
index 76f2b4c6712..1ff965f563e 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp
@@ -44,7 +44,9 @@ void test_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp
index 31f33a265c6..e440a95991c 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp
@@ -58,7 +58,9 @@ void test_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp
index 886fc95d9de..4fa94f137ce 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp
@@ -19,7 +19,7 @@ struct V {
   int member;
 };
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<V[]> p;
   std::unique_ptr<V[]> const& cp = p;
 
@@ -28,4 +28,6 @@ int main() {
 
   cp->member; // expected-error {{member reference type 'const std::unique_ptr<V []>' is not a pointer}}
               // expected-error@-1 {{no member named 'member'}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp
index 0bc0c7718b8..f31ca6b286d 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp
@@ -21,7 +21,9 @@ struct A {
   A() : i_(7) {}
 };
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<A> p(new A);
   assert(p->i_ == 7);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp
index 2b97f8fe569..21e7e661688 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp
@@ -33,7 +33,7 @@ public:
 
 int A::next_ = 0;
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<A[]> p(new A[3]);
   assert(p[0] == 1);
   assert(p[1] == 2);
@@ -44,4 +44,6 @@ int main() {
   assert(p[0] == 3);
   assert(p[1] == 2);
   assert(p[2] == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp
index e5a960a6e80..66286aa8620 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp
@@ -15,9 +15,11 @@
 #include <memory>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<int> p(new int[3]);
   std::unique_ptr<int> const& cp = p;
   p[0];  // expected-error {{type 'std::unique_ptr<int>' does not provide a subscript operator}}
   cp[1]; // expected-error {{type 'const std::unique_ptr<int>' does not provide a subscript operator}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp
index a77194ecf95..715335eb1cd 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp
@@ -21,7 +21,7 @@ private:
     int val_;
     };
 
-int main()
+int main(int, char**)
 {
     {
     auto p1 = std::make_unique<int[]>(5);
@@ -40,4 +40,6 @@ int main()
     for ( int i = 0; i < 7; ++i )
         assert ( p3[i].get () == 3 );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp
index a0e256fcf1e..56adccf176a 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up1 = std::make_unique<std::string[]>("error"); // doesn't compile - no bound
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp
index 0f366c6c3e2..fda45ab8946 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up2 = std::make_unique<int[]>(10, 20, 30, 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp
index 90622fed107..9fa05c79d93 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up3 = std::make_unique<int[5]>();    // this is deleted
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp
index 5c10ac6bb24..d98f052b54f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up4 = std::make_unique<int[5]>(11, 22, 33, 44, 55); // deleted
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp
index 4adf2e9ae42..08062c122e1 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp
@@ -11,7 +11,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     std::unique_ptr<int> p1 = std::make_unique<int>(1);
@@ -28,4 +28,6 @@ int main()
     p2 = std::make_unique<std::string> ( 6, 'z' );
     assert ( *p2 == "zzzzzz" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
index 85605a2fc42..6b8407c571a 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
@@ -34,7 +34,7 @@ struct B
 
 int B::count = 0;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<B> d2;
     std::default_delete<A> d1 = d2;
@@ -44,4 +44,6 @@ int main()
     d1(p);
     assert(A::count == 0);
     assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp
index c0a10e5e3eb..e7cbeaba5e0 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp
@@ -23,11 +23,13 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A> d;
     A* p = new A;
     assert(A::count == 1);
     d(p);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp
index b09640215a2..75f02d7c6c6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp
@@ -17,9 +17,11 @@
 
 struct A;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A> d;
     A* p = 0;
     d(p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp
index d03468c0380..3bffeb57694 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp
@@ -15,9 +15,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::default_delete<const void> d;
     const void* p = 0;
     d(p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp
index 699d20ed4f7..4a2bb5f7da7 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp
@@ -24,8 +24,10 @@ struct B
 {
 };
 
-int main()
+int main(int, char**)
 {
     std::default_delete<B[]> d2;
     std::default_delete<A[]> d1 = d2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp
index c2bfd31de1c..14e210598c1 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp
@@ -19,9 +19,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::default_delete<int[]> d1;
     std::default_delete<const int[]> d2 = d1;
     ((void)d2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp
index 246cf9d8dc5..9b220462b67 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp
@@ -25,11 +25,13 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A[]> d;
     A* p = new A[3];
     assert(A::count == 3);
     d(p);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp
index 48ac045526e..54fe0fcf793 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp
@@ -17,9 +17,11 @@
 
 struct A;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A[]> d;
     A* p = 0;
     d(p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp
index 774bc62d21b..52c399e64f7 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp
@@ -40,7 +40,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     const std::unique_ptr<int> p1(new int(1));
     assert(!(p1 == nullptr));
@@ -65,4 +65,6 @@ int main()
     assert(!(nullptr > p2));
     assert( (p2 >= nullptr));
     assert( (nullptr >= p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
index e1f3e762d69..ce83b575031 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
@@ -44,7 +44,7 @@ struct B
 
 int B::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const std::unique_ptr<A, Deleter<A> > p1(new A);
@@ -82,4 +82,6 @@ int main()
     assert(p1 == p2);
     assert(!(p1 != p2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
index 167dd7826c5..5fad4beb6c6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
@@ -52,7 +52,7 @@ struct B
 
 int B::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const std::unique_ptr<A, Deleter<A> > p1(new A);
@@ -96,4 +96,6 @@ int main()
     assert((p1 < p2) == !(p1 <= p2));
     assert((p1 < p2) == !(p1 >= p2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp
index 67cb170e4f9..4e45bbaef35 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp
@@ -44,7 +44,7 @@ private:
 
 };
 
-int main()
+int main(int, char**)
 {
     {
     A* p1 = new A(1);
@@ -98,4 +98,6 @@ int main()
         std::swap(p, p2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
index 8219296523b..ee6405bde1e 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
@@ -46,7 +46,7 @@ void test_char_pointer_ctor()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_char_pointer_ctor<0>();
     test_char_pointer_ctor<1>();
@@ -57,4 +57,6 @@ int main()
     test_char_pointer_ctor<64>();
     test_char_pointer_ctor<65>();
     test_char_pointer_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
index 0c88ba36ab6..bb5de6b18c7 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
@@ -35,7 +35,7 @@ void test_default_ctor()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_default_ctor<0>();
     test_default_ctor<1>();
@@ -46,4 +46,6 @@ int main()
     test_default_ctor<64>();
     test_default_ctor<65>();
     test_default_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp
index f5052b5efbb..453db91f29d 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp
@@ -74,7 +74,7 @@ void test_string_ctor()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_string_ctor<0>();
     test_string_ctor<1>();
@@ -85,4 +85,6 @@ int main()
     test_string_ctor<64>();
     test_string_ctor<65>();
     test_string_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
index a09ce57e346..4697d8bd380 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
@@ -39,7 +39,7 @@ void test_val_ctor()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_val_ctor<0>();
     test_val_ctor<1>();
@@ -50,4 +50,6 @@ int main()
     test_val_ctor<64>();
     test_val_ctor<65>();
     test_val_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp
index 95347a2bc53..dfac9d94af7 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp
@@ -38,10 +38,12 @@ test()
     ((void)result); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test<0>();
     test<10>();
     test<100>();
     test<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp
index 05d286f9058..a499b66fdb5 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::bitset<0> >();
@@ -25,4 +25,6 @@ int main() {
     test_hash_enabled_for_type<std::bitset<1024> >();
     test_hash_enabled_for_type<std::bitset<100000> >();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp
index 4ac3bae75a8..fe9e0e0a363 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp
@@ -28,7 +28,7 @@ void test_all()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_all<0>();
     test_all<1>();
@@ -39,4 +39,6 @@ int main()
     test_all<64>();
     test_all<65>();
     test_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp
index 0483a04ffa2..95b640178b9 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp
@@ -31,7 +31,7 @@ void test_any()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_any<0>();
     test_any<1>();
@@ -42,4 +42,6 @@ int main()
     test_any<64>();
     test_any<65>();
     test_any<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp
index 9b66e93e25f..5b04666bc2a 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp
@@ -42,7 +42,7 @@ void test_count()
     assert(c1 == c2);
 }
 
-int main()
+int main(int, char**)
 {
     test_count<0>();
     test_count<1>();
@@ -53,4 +53,6 @@ int main()
     test_count<64>();
     test_count<65>();
     test_count<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp
index b3f515c0c3f..14bd9eadf98 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp
@@ -40,7 +40,7 @@ void test_flip_all()
         assert(v2[i] == ~v1[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_flip_all<0>();
     test_flip_all<1>();
@@ -51,4 +51,6 @@ int main()
     test_flip_all<64>();
     test_flip_all<65>();
     test_flip_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp
index 96569e565e6..235b7e1a7ae 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp
@@ -58,7 +58,7 @@ void test_flip_one(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_flip_one<0>(true);
     test_flip_one<1>(true);
@@ -69,4 +69,6 @@ int main()
     test_flip_one<64>(false);
     test_flip_one<65>(false);
     test_flip_one<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp
index fb68df5aa38..a6eea145007 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp
@@ -60,7 +60,7 @@ void test_index_const()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_index_const<0>();
     test_index_const<1>();
@@ -71,4 +71,6 @@ int main()
     test_index_const<64>();
     test_index_const<65>();
     test_index_const<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp
index 54a1a31c0db..9c6e28a8894 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp
@@ -42,7 +42,7 @@ void test_index_const()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_index_const<0>();
     test_index_const<1>();
@@ -53,4 +53,6 @@ int main()
     test_index_const<64>();
     test_index_const<65>();
     test_index_const<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp
index 27a20b4f64a..59a7954a0df 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp
@@ -41,7 +41,7 @@ void test_left_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_left_shift<0>();
     test_left_shift<1>();
@@ -52,4 +52,6 @@ int main()
     test_left_shift<64>();
     test_left_shift<65>();
     test_left_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp
index c3becacd333..ad307ae8262 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp
@@ -46,7 +46,7 @@ void test_left_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_left_shift<0>();
     test_left_shift<1>();
@@ -57,4 +57,6 @@ int main()
     test_left_shift<64>();
     test_left_shift<65>();
     test_left_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp
index d5004fbb686..2588ac60f7b 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp
@@ -31,7 +31,7 @@ void test_none()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_none<0>();
     test_none<1>();
@@ -42,4 +42,6 @@ int main()
     test_none<64>();
     test_none<65>();
     test_none<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp
index 87c3efd1fc3..17b2d4293ac 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp
@@ -39,7 +39,7 @@ void test_not_all()
         assert(v2[i] == ~v1[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_not_all<0>();
     test_not_all<1>();
@@ -50,4 +50,6 @@ int main()
     test_not_all<64>();
     test_not_all<65>();
     test_not_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp
index 38564bba5f8..8560be2467e 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp
@@ -41,7 +41,7 @@ void test_op_and_eq()
         assert(v1[i] == (v3[i] && v2[i]));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_and_eq<0>();
     test_op_and_eq<1>();
@@ -52,4 +52,6 @@ int main()
     test_op_and_eq<64>();
     test_op_and_eq<65>();
     test_op_and_eq<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp
index 7c428bce061..d2363023e62 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp
@@ -48,7 +48,7 @@ void test_equality()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_equality<0>();
     test_equality<1>();
@@ -59,4 +59,6 @@ int main()
     test_equality<64>();
     test_equality<65>();
     test_equality<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp
index f96c77bc2e6..42d525e5b49 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp
@@ -41,7 +41,7 @@ void test_op_or_eq()
         assert(v1[i] == (v3[i] || v2[i]));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_or_eq<0>();
     test_op_or_eq<1>();
@@ -52,4 +52,6 @@ int main()
     test_op_or_eq<64>();
     test_op_or_eq<65>();
     test_op_or_eq<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp
index 647c5c028be..44d58d8a155 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp
@@ -41,7 +41,7 @@ void test_op_xor_eq()
         assert(v1[i] == (v3[i] != v2[i]));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_xor_eq<0>();
     test_op_xor_eq<1>();
@@ -52,4 +52,6 @@ int main()
     test_op_xor_eq<64>();
     test_op_xor_eq<65>();
     test_op_xor_eq<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp
index ae43bd7e99f..91041176ddb 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp
@@ -29,7 +29,7 @@ void test_reset_all()
         assert(!v[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_reset_all<0>();
     test_reset_all<1>();
@@ -40,4 +40,6 @@ int main()
     test_reset_all<64>();
     test_reset_all<65>();
     test_reset_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp
index ec92f6656b3..1abb4914bfa 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp
@@ -43,7 +43,7 @@ void test_reset_one(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_reset_one<0>(true);
     test_reset_one<1>(true);
@@ -54,4 +54,6 @@ int main()
     test_reset_one<64>(false);
     test_reset_one<65>(false);
     test_reset_one<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp
index a94f9bf0921..e05c3316bb5 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp
@@ -41,7 +41,7 @@ void test_right_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_right_shift<0>();
     test_right_shift<1>();
@@ -52,4 +52,6 @@ int main()
     test_right_shift<64>();
     test_right_shift<65>();
     test_right_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
index 387f68249e3..f23fbeebc87 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
@@ -46,7 +46,7 @@ void test_right_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_right_shift<0>();
     test_right_shift<1>();
@@ -57,4 +57,6 @@ int main()
     test_right_shift<64>();
     test_right_shift<65>();
     test_right_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp
index 68f8c58bb2c..ca4708cc43e 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp
@@ -28,7 +28,7 @@ void test_set_all()
         assert(v[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_set_all<0>();
     test_set_all<1>();
@@ -39,4 +39,6 @@ int main()
     test_set_all<64>();
     test_set_all<65>();
     test_set_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp
index f660a440947..f723eebe085 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp
@@ -52,7 +52,7 @@ void test_set_one(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_set_one<0>(true);
     test_set_one<1>(true);
@@ -63,4 +63,6 @@ int main()
     test_set_one<64>(false);
     test_set_one<65>(false);
     test_set_one<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp
index f1719ab2e41..41318d99eef 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp
@@ -18,7 +18,7 @@ void test_size()
     assert(v.size() == N);
 }
 
-int main()
+int main(int, char**)
 {
     test_size<0>();
     test_size<1>();
@@ -29,4 +29,6 @@ int main()
     test_size<64>();
     test_size<65>();
     test_size<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp
index df3ee16be7e..5d566f5d0cf 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp
@@ -53,7 +53,7 @@ void test_test(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_test<0>(true);
     test_test<1>(true);
@@ -64,4 +64,6 @@ int main()
     test_test<64>(false);
     test_test<65>(false);
     test_test<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp
index d8979447296..3897e10375f 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp
@@ -153,7 +153,7 @@ void test_to_string()
 }
 }
 
-int main()
+int main(int, char**)
 {
     test_to_string<0>();
     test_to_string<1>();
@@ -164,4 +164,6 @@ int main()
     test_to_string<64>();
     test_to_string<65>();
     test_to_string<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
index 1ea9b0f81f1..c43ef90aeef 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
@@ -44,7 +44,7 @@ void test_to_ullong()
     }
 }
 
-int main()
+int main(int, char**)
 {
 //     test_to_ullong<0>();
     test_to_ullong<1>();
@@ -55,4 +55,6 @@ int main()
     test_to_ullong<64>();
     test_to_ullong<65>();
     test_to_ullong<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
index 71910f322b2..c6cf6b19a18 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
@@ -46,7 +46,7 @@ void test_to_ulong()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_to_ulong<0>();
     test_to_ulong<1>();
@@ -57,4 +57,6 @@ int main()
     test_to_ulong<64>();
     test_to_ulong<65>();
     test_to_ulong<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp
index af69d3951b7..21d5d08058c 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp
@@ -39,7 +39,7 @@ void test_op_and()
     assert((v1 & v2) == (v3 &= v2));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_and<0>();
     test_op_and<1>();
@@ -50,4 +50,6 @@ int main()
     test_op_and<64>();
     test_op_and<65>();
     test_op_and<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp
index 8d9b2bdfb29..4a71385a941 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp
@@ -39,7 +39,7 @@ void test_op_not()
     assert((v1 ^ v2) == (v3 ^= v2));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_not<0>();
     test_op_not<1>();
@@ -50,4 +50,6 @@ int main()
     test_op_not<64>();
     test_op_not<65>();
     test_op_not<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp
index c2cada15ea1..bc4847c19e4 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp
@@ -39,7 +39,7 @@ void test_op_or()
     assert((v1 | v2) == (v3 |= v2));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_or<0>();
     test_op_or<1>();
@@ -50,4 +50,6 @@ int main()
     test_op_or<64>();
     test_op_or<65>();
     test_op_or<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp
index 714fcd3ed2f..9abe19c7c87 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream in("01011010");
     std::bitset<8> b;
     in >> b;
     assert(b.to_ulong() == 0x5A);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp
index 06a36604ac4..2c4ce1e4881 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream os;
     std::bitset<8> b(0x5A);
     os << b;
     assert(os.str() == "01011010");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/includes.pass.cpp b/libcxx/test/std/utilities/template.bitset/includes.pass.cpp
index c98b150e792..90695ed3dcc 100644
--- a/libcxx/test/std/utilities/template.bitset/includes.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/includes.pass.cpp
@@ -12,7 +12,7 @@
 
 template <class> void test_typedef() {}
 
-int main()
+int main(int, char**)
 {
   { // test for <string>
     std::string s; ((void)s);
@@ -24,4 +24,6 @@ int main()
     test_typedef<std::ostream>();
     test_typedef<std::iostream>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp b/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
index 3fa04b77999..ac29fd78180 100644
--- a/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
+++ b/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
@@ -29,7 +29,7 @@
 #pragma GCC diagnostic ignored "-Wformat-zero-length"
 #endif
 
-int main()
+int main(int, char**)
 {
     std::clock_t c = 0;
     std::size_t s = 0;
@@ -60,4 +60,6 @@ int main()
     static_assert((std::is_same<decltype(std::localtime(&t)), std::tm*>::value), "");
 #endif
     static_assert((std::is_same<decltype(std::strftime(str,s,"",&tm)), std::size_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/days.pass.cpp b/libcxx/test/std/utilities/time/days.pass.cpp
index a22f97b8f52..43b53ea33cb 100644
--- a/libcxx/test/std/utilities/time/days.pass.cpp
+++ b/libcxx/test/std/utilities/time/days.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::days D;
     typedef D::rep Rep;
@@ -24,4 +24,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 25, "");
     static_assert(std::is_same_v<Period, std::ratio_multiply<std::ratio<24>, std::chrono::hours::period>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/hours.pass.cpp b/libcxx/test/std/utilities/time/hours.pass.cpp
index e04888f2e2a..97fc2621b6a 100644
--- a/libcxx/test/std/utilities/time/hours.pass.cpp
+++ b/libcxx/test/std/utilities/time/hours.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::hours D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 22, "");
     static_assert((std::is_same<Period, std::ratio<3600> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/microseconds.pass.cpp b/libcxx/test/std/utilities/time/microseconds.pass.cpp
index 20e12a9a288..ded1c22fe14 100644
--- a/libcxx/test/std/utilities/time/microseconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/microseconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::microseconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 54, "");
     static_assert((std::is_same<Period, std::micro>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/milliseconds.pass.cpp b/libcxx/test/std/utilities/time/milliseconds.pass.cpp
index 6183b929f19..b1fe99e1209 100644
--- a/libcxx/test/std/utilities/time/milliseconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/milliseconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::milliseconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 44, "");
     static_assert((std::is_same<Period, std::milli>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/minutes.pass.cpp b/libcxx/test/std/utilities/time/minutes.pass.cpp
index 413d8cd6f69..23f0bf2877d 100644
--- a/libcxx/test/std/utilities/time/minutes.pass.cpp
+++ b/libcxx/test/std/utilities/time/minutes.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::minutes D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 28, "");
     static_assert((std::is_same<Period, std::ratio<60> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/months.pass.cpp b/libcxx/test/std/utilities/time/months.pass.cpp
index ff40823f1ea..b14b2fab533 100644
--- a/libcxx/test/std/utilities/time/months.pass.cpp
+++ b/libcxx/test/std/utilities/time/months.pass.cpp
@@ -16,7 +16,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::months D;
     typedef D::rep Rep;
@@ -25,4 +25,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 20, "");
     static_assert(std::is_same_v<Period, std::ratio_divide<std::chrono::years::period, std::ratio<12>>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/nanoseconds.pass.cpp b/libcxx/test/std/utilities/time/nanoseconds.pass.cpp
index c14389da728..d58a375c2a5 100644
--- a/libcxx/test/std/utilities/time/nanoseconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/nanoseconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::nanoseconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 63, "");
     static_assert((std::is_same<Period, std::nano>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/seconds.pass.cpp b/libcxx/test/std/utilities/time/seconds.pass.cpp
index bd2d6d2b3f5..45a3f1d8e7f 100644
--- a/libcxx/test/std/utilities/time/seconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/seconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::seconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 34, "");
     static_assert((std::is_same<Period, std::ratio<1> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
index 3a3978cb082..5c945fab75e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
 
@@ -42,4 +42,6 @@ int main()
         day day(i);
         assert(static_cast<unsigned>(day) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
index c53af65112e..f5323f65956 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     ASSERT_NOEXCEPT(--(std::declval<day&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<unsigned>(day--) == i - 1);
         assert(static_cast<unsigned>(day)   == i - 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
index b26d2285aa4..0be8c847f30 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     ASSERT_NOEXCEPT(++(std::declval<day&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<unsigned>(day++) == i + 1);
         assert(static_cast<unsigned>(day)   == i + 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp
index 8a04298ab3c..131df7533c6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     ASSERT_NOEXCEPT(                std::declval<const day>().ok());
@@ -33,4 +33,6 @@ int main()
         assert(day{i}.ok());
     for (unsigned i = 32; i <= 255; ++i)
         assert(!day{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
index 42f12af552e..d182d6c926f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day  = std::chrono::day;
     using days = std::chrono::days;
@@ -53,4 +53,6 @@ int main()
         assert(static_cast<unsigned>(day -= days{12}) == i + 10);
         assert(static_cast<unsigned>(day)             == i + 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp
index 6b8a4277272..75bc4cf529a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
 
@@ -40,4 +40,6 @@ int main()
     for (unsigned i = 1; i < 10; ++i)
         for (unsigned j = 1; j < 10; ++j)
             assert(testComparisons6Values<day>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp
index 36352fa35d6..6331bcf1b23 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     day d1 = 4d; // expected-error-re {{no matching literal operator for call to 'operator""d' {{.*}}}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
index b3febd4ebe2..a887736f6e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     using namespace std::chrono;
@@ -43,4 +43,6 @@ int main()
     assert (d1 == std::chrono::day(4));
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp
index 4953d1afe4e..e8ade305adc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day  = std::chrono::day;
     using days = std::chrono::days;
@@ -54,4 +54,6 @@ int main()
         assert(static_cast<unsigned>(d1) == 12 - i);
         assert(off.count() == static_cast<int>(12 - i)); // days is signed
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp
index 10cec0a62d8..e219c7d3c7a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day  = std::chrono::day;
     using days = std::chrono::days;
@@ -55,4 +55,6 @@ int main()
         assert(static_cast<unsigned>(d1) == i + 12);
         assert(static_cast<unsigned>(d2) == i + 12);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp
index ad3d4f3f9e6..23ce736c61d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp
@@ -48,8 +48,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using day = std::chrono::day;
    std::cout << day{1};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp
index d437a6ae3f4..3c26c57535f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
 
     static_assert(std::is_trivially_copyable_v<day>, "");
     static_assert(std::is_standard_layout_v<day>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp
index 10396919bd4..084a6aa8dc5 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using last_spec = std::chrono::last_spec;
 
@@ -29,4 +29,6 @@ int main()
 
     static_assert(std::is_trivially_copyable_v<last_spec>, "");
     static_assert(std::is_standard_layout_v<last_spec>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp
index f3dadd2f6b0..48642987a7c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -43,4 +43,6 @@ int main()
     static_assert( md1.month() == std::chrono::January, "");
     static_assert( md1.day()   == day{4},               "");
     static_assert( md1.ok(),                            "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp
index c9c247d508f..7137433a9fb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month_day = std::chrono::month_day;
@@ -34,4 +34,6 @@ int main()
         month_day md(std::chrono::March, day{i});
         assert( static_cast<unsigned>(md.day()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp
index e1b46190f0a..b4744e6d4c7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -35,4 +35,6 @@ int main()
         month_day md(month{i}, day{1});
         assert( static_cast<unsigned>(md.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp
index 649f0996867..5e4c0082f5f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -51,4 +51,6 @@ int main()
 //  If the month is not ok, all the days are bad
     for (unsigned i = 1; i <= 35; ++i)
         assert(!(month_day{month{13}, day{i}}.ok()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp
index c186f594c64..d7e535a72e7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -66,4 +66,6 @@ int main()
                 month_day{month{2}, day{j}},
                 i == j, i < j )));
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp
index dbebdfa7d0e..8eef5f03095 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp
@@ -31,10 +31,12 @@
 #include <iostream>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day = std::chrono::month_day;
     using month     = std::chrono::month;
     using day       = std::chrono::day;
     std::cout << month_day{month{1}, day{1}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp
index ba7c336a634..507855a990f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day = std::chrono::month_day;
 
     static_assert(std::is_trivially_copyable_v<month_day>, "");
     static_assert(std::is_standard_layout_v<month_day>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp
index ba9eda73a4a..265e7be372d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month          = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -39,4 +39,6 @@ int main()
     for (unsigned i = 1; i < 12; ++i)
         for (unsigned j = 1; j < 12; ++j)
             assert((testComparisons6Values<month_day_last>(month{i}, month{j})));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp
index 4bf983f3b40..3696bb907d8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month     = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -37,4 +37,6 @@ int main()
     constexpr month_day_last md1{std::chrono::January};
     static_assert( md1.month() == std::chrono::January, "");
     static_assert( md1.ok(),                            "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp
index b9945b6d88d..6bf75892da9 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month     = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -34,4 +34,6 @@ int main()
         month_day_last mdl(month{i});
         assert( static_cast<unsigned>(mdl.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp
index 38c52e22958..730ab3b25d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month          = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -42,4 +42,6 @@ int main()
         month_day_last mdl{month{i}};
         assert(!mdl.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp
index ebb91559854..1b4a8f108cb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp
@@ -25,9 +25,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day_last = std::chrono::month_day_last;
     using month          = std::chrono::month;
     std::cout << month_day_last{month{1}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp
index e3f02a88549..c6eebc42de1 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day_last = std::chrono::month_day_last;
 
     static_assert(std::is_trivially_copyable_v<month_day_last>, "");
     static_assert(std::is_standard_layout_v<month_day_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp
index d0ed4d37d01..6800a03e18a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -42,4 +42,6 @@ int main()
         month m(i);
         assert(static_cast<unsigned>(m) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
index 2cab328cfcb..6d7edc508c1 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -49,4 +49,6 @@ int main()
         assert(static_cast<unsigned>(month--) == i - 1);
         assert(static_cast<unsigned>(month)   == i - 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
index 81162edf6ca..7bcd5bed716 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
     ASSERT_NOEXCEPT(++(std::declval<month&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<unsigned>(month++) == i + 1);
         assert(static_cast<unsigned>(month)   == i + 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp
index 7cb5edad47f..a001c74a3fa 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -34,4 +34,6 @@ int main()
         assert(month{i}.ok());
     for (unsigned i = 13; i <= 255; ++i)
         assert(!month{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
index 7ca4a6e5f4c..a792072afa2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month  = std::chrono::month;
     using months = std::chrono::months;
@@ -63,4 +63,6 @@ int main()
         assert(static_cast<unsigned>(month -= months{ 9}) == static_cast<unsigned>(exp));
         assert(static_cast<unsigned>(month)               == static_cast<unsigned>(exp));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp
index aa37fde3b29..f69fec8aaac 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_comparisons.h"
 
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -43,4 +43,6 @@ int main()
     for (unsigned i = 1; i < 10; ++i)
         for (unsigned j = 10; j < 10; ++j)
             assert(testComparisons6Values<month>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp
index 807cf29881b..9832fe37681 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 
     ASSERT_SAME_TYPE(const std::chrono::month, decltype(std::chrono::January));
@@ -83,4 +83,6 @@ int main()
     assert(static_cast<unsigned>(std::chrono::October)   == 10);
     assert(static_cast<unsigned>(std::chrono::November)  == 11);
     assert(static_cast<unsigned>(std::chrono::December)  == 12);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp
index 291d299e3af..cda36412741 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp
@@ -44,7 +44,7 @@ constexpr bool testConstexpr()
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
     using month  = std::chrono::month;
     using months = std::chrono::months;
@@ -68,4 +68,6 @@ static_assert(testConstexpr<month, months>(), "");
         assert(static_cast<unsigned>(m1) == static_cast<unsigned>(exp));
 //          assert(off.count()               == static_cast<unsigned>(exp));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp
index 87b39003b1e..58a951e1b0e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp
@@ -43,7 +43,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month  = std::chrono::month;
     using months = std::chrono::months;
@@ -68,4 +68,6 @@ int main()
         assert(static_cast<unsigned>(m1) == exp);
         assert(static_cast<unsigned>(m2) == exp);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp
index 5f3f3884f6b..1d3aa7ce4e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp
@@ -45,8 +45,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using month = std::chrono::month;
    std::cout << month{1};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp
index b3e5024656f..a6e67f10134 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
     static_assert(std::is_trivially_copyable_v<month>, "");
     static_assert(std::is_standard_layout_v<month>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp
index 8d0b560b1fd..8804e71e3e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -42,4 +42,6 @@ int main()
     static_assert( md1.month() == std::chrono::January,                              "");
     static_assert( md1.weekday_indexed() == weekday_indexed{std::chrono::Friday, 4}, "");
     static_assert( md1.ok(),                                                         "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp
index 99bdcb1607c..35e7c83c792 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -38,4 +38,6 @@ int main()
         month_weekday md(month{i}, weekday_indexed{Sunday, 1});
         assert( static_cast<unsigned>(md.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp
index b4999652fd5..2ff1bf735f2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -47,4 +47,6 @@ int main()
 //  If the month is not ok, all the weekday_indexed are bad
     for (unsigned i = 1; i <= 10; ++i)
         assert(!(month_weekday{month{13}, weekday_indexed{Sunday, i}}.ok()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp
index d80ae29d048..13a1bba53dd 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -39,4 +39,6 @@ int main()
         assert( static_cast<unsigned>(md.weekday_indexed().weekday() == Sunday));
         assert( static_cast<unsigned>(md.weekday_indexed().index() == i));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp
index 64df8840e74..46f756de06c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -82,4 +82,6 @@ int main()
                 month_weekday{month{2}, weekday_indexed{weekday{i}, 2}},
                 month_weekday{month{2}, weekday_indexed{weekday{j}, 2}},
                 i == j)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp
index e7981b5713a..11a1d4ecd04 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -32,4 +32,6 @@ int main()
     using weekday         = std::chrono::weekday;
 
     std::cout << month_weekday{month{1}, weekday_indexed{weekday{3}, 3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp
index 67c3f17b946..bd4f4e1d492 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday = std::chrono::month_weekday;
 
     static_assert(std::is_trivially_copyable_v<month_weekday>, "");
     static_assert(std::is_standard_layout_v<month_weekday>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp
index fa5ca044358..d83bbe92f11 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -56,4 +56,6 @@ int main()
     static_assert( mwdl3.month() == January,                         "");
     static_assert( mwdl3.weekday_last() == weekday_last{weekday{4}}, "");
     static_assert( mwdl3.ok(),                                       "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp
index 3561651c28a..a32b0899615 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -38,4 +38,6 @@ int main()
         month_weekday_last mdl(month{i}, weekday_last{Tuesday});
         assert( static_cast<unsigned>(mdl.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp
index 10245f938d6..02df5fbd22b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -48,4 +48,6 @@ int main()
         month_weekday_last mwdl{January, weekday_last{weekday{i}}};
         assert( mwdl.ok() == weekday_last{weekday{i}}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
index 4afa6cca734..4ecf6d24628 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -40,4 +40,6 @@ int main()
         month_weekday_last mdl(January, weekday_last{weekday{i}});
         assert( static_cast<unsigned>(mdl.weekday_last().weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp
index 4d0e935f11a..911693c25bf 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday_last       = std::chrono::weekday_last;
@@ -69,4 +69,6 @@ int main()
             month_weekday_last{month{1}, weekday_last{weekday{1}}},
             month_weekday_last{month{2}, weekday_last{weekday{2}}},
         false)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp
index 2bf0e1ec43b..75654b1b3a2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday_last = std::chrono::month_weekday_last;
     using month              = std::chrono::month;
@@ -33,4 +33,6 @@ int main()
     using weekday_last       = std::chrono::weekday_last;
 
     std::cout << month_weekday_last{month{1}, weekday_last{weekday{3}}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp
index 2271f42c031..2f2676d7a52 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday_last = std::chrono::month_weekday_last;
 
     static_assert(std::is_trivially_copyable_v<month_weekday_last>, "");
     static_assert(std::is_standard_layout_v<month_weekday_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp
index e51fb4fa47e..e9eb80bfd98 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp
@@ -38,7 +38,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_day = std::chrono::month_day;
     using month     = std::chrono::month;
@@ -104,4 +104,6 @@ int main()
                 assert(md1 == md2);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp
index 27043b88c63..84c2c6eaa39 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp
@@ -46,7 +46,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month          = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -103,4 +103,6 @@ int main()
         }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp
index 4dc6db768e2..60b788de1e4 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp
@@ -44,7 +44,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -111,4 +111,6 @@ int main()
                     assert(mwd1 == mwd2);
                 }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp
index 25d25b26d9b..07e5d8d75d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp
@@ -36,7 +36,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday      = std::chrono::month_weekday;
     using month              = std::chrono::month;
@@ -103,4 +103,6 @@ int main()
                 assert(mwd1 == mwd2);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp
index 6ef320ebb79..ba2b5c187f6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using year       = std::chrono::year;
@@ -64,4 +64,6 @@ int main()
                 assert(static_cast<unsigned>(ym.month()) == j);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp
index a8df7009632..a5aa4d0ef59 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp
@@ -42,7 +42,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -187,4 +187,6 @@ int main()
                 }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp
index 2556bb93f36..fd55e38b4c4 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp
@@ -38,7 +38,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month               = std::chrono::month;
     using year_month          = std::chrono::year_month;
@@ -121,4 +121,6 @@ int main()
                 assert(ymdl1 == ymdl2);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp
index af27c945e09..4e71435805a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp
@@ -37,7 +37,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using year_month         = std::chrono::year_month;
@@ -141,4 +141,6 @@ int main()
                         assert(ymd1 == ymd2);
                     }
      }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp
index ff467aa60c3..62b1f46765c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp
@@ -39,7 +39,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year_month         = std::chrono::year_month;
     using year               = std::chrono::year;
@@ -149,4 +149,6 @@ int main()
                     assert(ymwdl1 == ymwdl2);
                 }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp
index b9facef63e7..4a64b932b68 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday  = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -57,4 +57,6 @@ int main()
         weekday_indexed wdi(std::chrono::Tuesday, i);
         assert(!wdi.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp
index 043a98accf5..4942f716480 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -34,4 +34,6 @@ int main()
         weekday_indexed wdi(weekday{2}, i);
         assert( static_cast<unsigned>(wdi.index()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp
index 1cdfb29c96e..a2b5b48e4fc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -45,4 +45,6 @@ int main()
 
 //  Not a valid weekday
     assert(!(weekday_indexed(weekday{9U}, 1).ok()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
index 47f50b6d672..e9c204d08b1 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -35,4 +35,6 @@ int main()
         weekday_indexed wdi(weekday{i}, 2);
         assert( static_cast<unsigned>(wdi.weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp
index 963f9f15ec8..104c59abf78 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -44,4 +44,6 @@ int main()
     static_assert( (weekday_indexed{weekday{1}, 2} != weekday_indexed{weekday{1}, 1}), "");
     static_assert(!(weekday_indexed{weekday{1}, 2} == weekday_indexed{weekday{2}, 2}),  "");
     static_assert( (weekday_indexed{weekday{1}, 2} != weekday_indexed{weekday{2}, 2}),  "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp
index 810b2cb0c49..5052a182458 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp
@@ -26,10 +26,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday_indexed = std::chrono::weekday_indexed;
     using weekday         = std::chrono::weekday;
 
     std::cout << weekday_indexed{weekday{3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp
index 74634da8a58..260b50f465d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday_indexed = std::chrono::weekday_indexed;
 
     static_assert(std::is_trivially_copyable_v<weekday_indexed>, "");
     static_assert(std::is_standard_layout_v<weekday_indexed>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp
index f7fa6632041..a569144d068 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -43,4 +43,6 @@ int main()
         weekday_last wdl{weekday{i}};
         assert(wdl.weekday() == weekday{i});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
index d708a812463..eb0636aa9cf 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -33,4 +33,6 @@ int main()
 
     for (unsigned i = 0; i <= 255; ++i)
         assert(weekday_last{weekday{i}}.ok() == weekday{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp
index 48767b3b86e..c5eb6e13201 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -29,4 +29,6 @@ int main()
 
     for (unsigned i = 0; i <= 255; ++i)
         assert(weekday_last{weekday{i}}.weekday() == weekday{i});
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp
index 1a9fc97eb51..c5ca36e8288 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -39,4 +39,6 @@ int main()
     for (unsigned i = 0; i < 6; ++i)
         for (unsigned j = 0; j < 6; ++j)
             assert(testComparisons2Values<weekday_last>(weekday{i}, weekday{j}));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp
index efb59847255..85a40a3dc4c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp
@@ -24,10 +24,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using weekday_last = std::chrono::weekday_last;
    using weekday      = std::chrono::weekday;
 
    std::cout << weekday_last{weekday{3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp
index c986f99c332..ff9d54f88da 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday_last = std::chrono::weekday_last;
 
     static_assert(std::is_trivially_copyable_v<weekday_last>, "");
     static_assert(std::is_standard_layout_v<weekday_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
index ee241c8e7c9..06656fb442a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using local_days = std::chrono::local_days;
     using days       = std::chrono::days;
@@ -69,4 +69,6 @@ int main()
     assert( wd.ok());
     assert(static_cast<unsigned>(wd) == 3);
     }
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
index 9ec3afb2144..470b9d79d23 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
@@ -47,4 +47,6 @@ int main()
     }
 
 // TODO - sys_days and local_days ctor tests
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
index 920b53e783c..e00184a9915 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using sys_days  = std::chrono::sys_days;
     using days      = std::chrono::days;
@@ -69,4 +69,6 @@ int main()
     assert( wd.ok());
     assert(static_cast<unsigned>(wd) == 3);
     }
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
index c8b023a37c5..d574e1db9b6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
@@ -31,7 +31,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     ASSERT_NOEXCEPT(--(std::declval<weekday&>())  );
@@ -49,4 +49,6 @@ int main()
         assert((static_cast<unsigned>(wd--) == euclidian_subtraction<unsigned, 0, 6>(i, 1)));
         assert((static_cast<unsigned>(wd)   == euclidian_subtraction<unsigned, 0, 6>(i, 2)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
index d9239ff8f90..bb62e0120ef 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
@@ -31,7 +31,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     ASSERT_NOEXCEPT(++(std::declval<weekday&>())  );
@@ -49,4 +49,6 @@ int main()
         assert((static_cast<unsigned>(wd++) == euclidian_addition<unsigned, 0, 6>(i, 1)));
         assert((static_cast<unsigned>(wd)   == euclidian_addition<unsigned, 0, 6>(i, 2)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
index f8bd9d43a25..f2f6e2e9802 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
@@ -34,4 +34,6 @@ int main()
         assert(weekday{i}.ok());
     for (unsigned i = 7; i <= 255; ++i)
         assert(!weekday{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp
index aa0f3f7e59e..d7d2d6faf30 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "../../euclidian.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_last    = std::chrono::weekday_last;
@@ -55,4 +55,6 @@ int main()
         assert(wdi.index() == j);
         assert(wdi.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
index e0963540cf2..d99b0349399 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     using days    = std::chrono::days;
@@ -59,4 +59,6 @@ int main()
         assert((static_cast<unsigned>(wd -= days{4}) == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
         assert((static_cast<unsigned>(wd)            == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp
index c042ac14778..982b3bccbc6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
@@ -38,4 +38,6 @@ int main()
     for (unsigned i = 0; i < 6; ++i)
         for (unsigned j = 0; j < 6; ++j)
             assert(testComparisons2Values<weekday>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
index 8f713aad280..7529864a5bb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 
     ASSERT_SAME_TYPE(const std::chrono::weekday, decltype(std::chrono::Sunday));
@@ -58,4 +58,6 @@ int main()
     assert(static_cast<unsigned>(std::chrono::Thursday)  ==  4);
     assert(static_cast<unsigned>(std::chrono::Friday)    ==  5);
     assert(static_cast<unsigned>(std::chrono::Saturday)  ==  6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
index 2bf0ed78995..f296fc6d68e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
@@ -44,7 +44,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday  = std::chrono::weekday;
     using days     = std::chrono::days;
@@ -72,4 +72,6 @@ int main()
             assert(weekday{i} + d == weekday{j});
         }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
index 287834cd7e8..78d332b96cb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
@@ -44,7 +44,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     using days    = std::chrono::days;
@@ -66,4 +66,6 @@ int main()
             assert((static_cast<unsigned>(wd1) == euclidian_addition<unsigned, 0, 6>(i, j)));
             assert((static_cast<unsigned>(wd2) == euclidian_addition<unsigned, 0, 6>(i, j)));
         }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp
index aef5a82e78d..43825b60e99 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp
@@ -47,9 +47,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using weekday = std::chrono::weekday;
 
    std::cout << weekday{3};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp
index ed355b02515..7264a210f59 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
     static_assert(std::is_trivially_copyable_v<weekday>, "");
     static_assert(std::is_standard_layout_v<weekday>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
index 5f8b4660a24..e46b5563064 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -42,4 +42,6 @@ int main()
         year year(i);
         assert(static_cast<int>(year) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
index e8473bf9810..893c48aab47 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
     ASSERT_NOEXCEPT(--(std::declval<year&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<int>(year--) == i - 1);
         assert(static_cast<int>(year)   == i - 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
index 759fb66617b..ef2a6f3fbee 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
     ASSERT_NOEXCEPT(++(std::declval<year&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<int>(year++) == i + 1);
         assert(static_cast<int>(year)   == i + 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp
index b1785b86c59..37031dbbabc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -49,4 +49,6 @@ int main()
     assert(!year{ 2003}.is_leap());
     assert( year{ 2004}.is_leap());
     assert(!year{ 2100}.is_leap());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp
index dfc2ad3ffe4..f56ee34d598 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -49,4 +49,6 @@ int main()
     assert(year{ 20001}.ok());
 
     static_assert(!year{-32768}.ok(), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
index 65b1494587b..0adb0f9fe58 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
 
@@ -46,4 +46,6 @@ int main()
         assert(static_cast<int>(+year) ==  i);
         assert(static_cast<int>(-year) == -i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
index a00a36f2dca..b79713ed1c8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
     using years = std::chrono::years;
@@ -53,4 +53,6 @@ int main()
         assert(static_cast<int>(year -= years{ 9}) == i +  1);
         assert(static_cast<int>(year)              == i +  1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp
index 8d675f4db39..9e84fe36ee0 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_comparisons.h"
 
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -43,4 +43,6 @@ int main()
     for (int i = 1; i < 10; ++i)
         for (int j = 1; j < 10; ++j)
             assert(testComparisons6Values<year>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp
index c6138c7af1c..50c7b7bc0a6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::chrono::year;
     year d1 = 1234y; // expected-error-re {{no matching literal operator for call to 'operator""y' {{.*}}}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp
index 6ebd0e66fdd..a2bec73e696 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     using namespace std::chrono;
@@ -40,4 +40,6 @@ int main()
     std::chrono::year y1 = 2020y;
     assert (y1 == std::chrono::year(2020));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp
index 3e3e0b77db4..f112345c0ad 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp
@@ -37,7 +37,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
     using years = std::chrono::years;
@@ -58,4 +58,6 @@ int main()
         assert(static_cast<int>(y1) == 1223 - i);
         assert(ys1.count()          == 1223 - i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp
index 15c713defb4..d73f6fc88b3 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
     using years = std::chrono::years;
@@ -55,4 +55,6 @@ int main()
         assert(static_cast<int>(y1) == i + 1223);
         assert(static_cast<int>(y2) == i + 1223);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp
index 2c52cde0a43..1b278f2b903 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp
@@ -46,9 +46,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using year = std::chrono::year;
 
    std::cout << year{2018};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp
index 10bea23a035..2acb0f104d3 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
     static_assert(std::is_trivially_copyable_v<year>, "");
     static_assert(std::is_standard_layout_v<year>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp
index 090a1ac212c..1c05cf7a6b6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -48,4 +48,6 @@ int main()
     static_assert( ym2.year()  == year{2018}, "");
     static_assert( ym2.month() == month{},    "");
     static_assert(!ym2.ok(),                  "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp
index 97334b20503..7e0cd17f467 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -35,4 +35,6 @@ int main()
         year_month ym(year{1234}, month{i});
         assert( static_cast<unsigned>(ym.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp
index 54e67dff9a3..463289ee43f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using year       = std::chrono::year;
@@ -46,4 +46,6 @@ int main()
         year_month ym{year{i}, January};
         assert( ym.ok() == year{i}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp
index 76f3b3355d2..a403462ff79 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using months     = std::chrono::months;
@@ -60,4 +60,6 @@ int main()
         assert(static_cast<unsigned>((ym             ).month()) == i + 1);
         assert(ym.year() == y);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp
index 05cd60844d9..adf08fc24b8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using year       = std::chrono::year;
@@ -61,4 +61,6 @@ int main()
         assert(static_cast<int>((ym            ).year()) == i + 1);
         assert(ym.month() == m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp
index e8476b04280..024f3140425 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -35,4 +35,6 @@ int main()
         year_month ym(year{i}, month{});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp
index e1ab033c7c7..d102b0a5620 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -65,4 +65,6 @@ int main()
             year_month{year{i}, std::chrono::January},
             year_month{year{j}, std::chrono::January},
             i == j, i < j )));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp
index 2999560f16f..d7756d10d25 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp
@@ -29,7 +29,7 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using years      = std::chrono::years;
@@ -86,4 +86,6 @@ int main()
 //  TODO: different year
 
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
index dc721adeedb..5698e724470 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
@@ -51,7 +51,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using years      = std::chrono::years;
@@ -102,4 +102,6 @@ int main()
         assert(ym1 == ym2);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp
index e75fc21bf88..43af6c2f719 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp
@@ -46,11 +46,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month = std::chrono::year_month;
     using year       = std::chrono::year;
     using month      = std::chrono::month;
 
     std::cout << year_month{year{2018}, month{3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp
index a3b9999f8fd..2e88c6bb6b6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month = std::chrono::year_month;
 
     static_assert(std::is_trivially_copyable_v<year_month>, "");
     static_assert(std::is_standard_layout_v<year_month>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp
index 9cebaa6836a..274cb6a266f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using day            = std::chrono::day;
@@ -81,4 +81,6 @@ int main()
     assert( ymd.month() == std::chrono::November);
     assert( ymd.day()   == day{29});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp
index a5818849add..fdef9517e4a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -52,4 +52,6 @@ int main()
     static_assert( ym1.day()   == day{12},    "");
     static_assert( ym1.ok(),                  "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp
index 7344c10c1ad..433468477d5 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using day            = std::chrono::day;
@@ -80,4 +80,6 @@ int main()
     assert( ymd.month() == std::chrono::November);
     assert( ymd.day()   == day{29});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp
index 913b403952b..d4e8fc83d5b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -76,4 +76,6 @@ int main()
     assert( ymd.day()   == day{28});
     assert( ymd.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp
index 12e1515b171..9a068737ddc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_day ymd(year{1234}, month{2}, day{i});
         assert( static_cast<unsigned>(ymd.day()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp
index 8c091d05165..f1dd2e6893a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_day ymd(year{1234}, month{i}, day{12});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp
index edb55f58b4c..cab639b820a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -92,4 +92,6 @@ int main()
         year_month_day ym{year{i}, January, day{12}};
         assert( ym.ok() == year{i}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp
index 02212dc9094..038d21c4670 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp
@@ -44,7 +44,7 @@ void RunTheExample()
     static_assert(year_month_day{local_days{year{2017}/January/32}} == year{2017}/February/1);  
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -90,4 +90,5 @@ int main()
     assert( year_month_day{sd} == ymd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp
index 5925cb0cb5c..a9568455085 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp
@@ -44,7 +44,7 @@ void RunTheExample()
     static_assert(year_month_day{sys_days{year{2017}/January/32}} == year{2017}/February/1);  
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -90,4 +90,5 @@ int main()
     assert( year_month_day{sd} == ymd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp
index 173b8b6a2fb..8530248d1d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -66,4 +66,6 @@ int main()
         assert(ym.year() == y);
         assert(ym.day()  == d);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp
index 1d995129152..ae134d1a240 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -66,4 +66,6 @@ int main()
         assert(ym.month() == m);
         assert(ym.day()   == d);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp
index 465fa9d93db..fc5a4072493 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_day ym(year{i}, month{}, day{});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp
index 8d5bf89553c..0d15589252a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using day        = std::chrono::day;
     using year       = std::chrono::year;
@@ -114,4 +114,6 @@ int main()
             year_month_day{year{i}, January, day{12}},
             year_month_day{year{j}, January, day{12}},
             i == j, i < j )));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp
index 4d5625ba739..3c921def3b8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool test_constexpr ()
         ;
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -56,4 +56,6 @@ int main()
         assert(ym1.month() == January);
         assert(ym1.day() == day{10});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp
index 2913eb23743..8d5e02543aa 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp
@@ -51,7 +51,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_day ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using day        = std::chrono::day;
     using year       = std::chrono::year;
@@ -108,4 +108,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp
index cce42bc616d..47b6f02490d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp
@@ -46,7 +46,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_day = std::chrono::year_month_day;
     using year           = std::chrono::year;
@@ -54,4 +54,6 @@ int main()
     using day            = std::chrono::day;
 
     std::cout << year_month_day{year{2018}, month{3}, day{12}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp
index c61d1c9960f..58acd143df9 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_day = std::chrono::year_month_day;
 
     static_assert(std::is_trivially_copyable_v<year_month_day>, "");
     static_assert(std::is_standard_layout_v<year_month_day>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp
index d27c3c67e5e..bd4729f6a0e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -49,4 +49,6 @@ int main()
     static_assert( ymdl1.month()          == January,                 "");
     static_assert( ymdl1.month_day_last() == month_day_last{January}, "");
     static_assert( ymdl1.ok(),                                        "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp
index 24682b6957f..2f0e2ba17a7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -47,4 +47,6 @@ int main()
     assert((year_month_day_last{year{2019}, month_day_last{month{ 2}}}.day() == day{28}));
     assert((year_month_day_last{year{2020}, month_day_last{month{ 2}}}.day() == day{29}));
     assert((year_month_day_last{year{2021}, month_day_last{month{ 2}}}.day() == day{28}));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp
index cf1024a8ce3..5b68aa1d95c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -34,4 +34,6 @@ int main()
         year_month_day_last ymd(year{1234}, month_day_last{month{i}});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp
index 5c99d947124..cca9026b650 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -34,4 +34,6 @@ int main()
         year_month_day_last ymdl(year{1234}, month_day_last{month{i}});
         assert( static_cast<unsigned>(ymdl.month_day_last().month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp
index bb4c410d449..d40de103c2a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -48,4 +48,6 @@ int main()
         year_month_day_last ym{year{i}, month_day_last{January}};
         assert( ym.ok() == year{i}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp
index 83f8b70dc79..a96dff338be 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month_day_last      = std::chrono::month_day_last;
@@ -57,4 +57,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+33)});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp
index 9a32112c901..250ca0f1123 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month_day_last      = std::chrono::month_day_last;
@@ -57,4 +57,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+33)});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp
index 2c4d1ff1f17..7091f64ea33 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -62,4 +62,6 @@ int main()
         assert(static_cast<unsigned>((ym             ).month()) == i + 1);
         assert(ym.year() == y);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp
index 00335e15d54..3c1ad352737 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -61,4 +61,6 @@ int main()
         assert(static_cast<int>((ymdl            ).year()) == i + 1);
         assert(ymdl.month_day_last() == mdl);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp
index 49387091d76..c0db150f96d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -34,4 +34,6 @@ int main()
         year_month_day_last ym(year{i}, month_day_last{month{}});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp
index 9db4b6aa6d9..c56491f96cb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -83,4 +83,6 @@ int main()
             year_month_day_last{year{i}, month_day_last{January}},
             year_month_day_last{year{j}, month_day_last{January}},
             i == j, i < j )));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp
index 7f5a796dfab..8ea3025d607 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp
@@ -47,7 +47,7 @@ constexpr bool testConstexprMonths (std::chrono::year_month_day_last ymdl)
         ;
 }
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -87,4 +87,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp
index c494620df6e..75cabbdcd28 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp
@@ -63,7 +63,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_day_last ymdl)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -118,4 +118,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp
index 268eb88fe17..eca8d3d6851 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_day_last = std::chrono::year_month_day_last;
     using year                = std::chrono::year;
@@ -33,4 +33,6 @@ int main()
     using month_day_last      = std::chrono::month_day_last;
 
     std::cout << year_month_day_last{year{2018}, month_day_last{month{3}}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp
index 0eae24e459c..bb4e7d04405 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using days               = std::chrono::days;
@@ -91,4 +91,6 @@ int main()
     assert((ymwd.weekday_indexed() == weekday_indexed{std::chrono::Wednesday, 5}));
     assert( ymwd                   == year_month_weekday{local_days{ymwd}}); // round trip
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp
index dab8b21577b..81030ff559d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -60,4 +60,6 @@ int main()
     static_assert( ym1.weekday_indexed() == weekday_indexed{Tuesday, 1}, "");
     static_assert( ym1.ok(),                                             "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp
index 96261c54e3c..5ae9900a983 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using days               = std::chrono::days;
@@ -90,4 +90,6 @@ int main()
     assert((ymwd.weekday_indexed() == weekday_indexed{std::chrono::Wednesday, 5}));
     assert( ymwd                   == year_month_weekday{sys_days{ymwd}}); // round trip
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp
index 4c0bc13c186..ecbd8aec830 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday ymwd0(year{1234}, month{2}, weekday_indexed{weekday{2}, i});
         assert(ymwd0.index() == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp
index 0e2d41a771f..c300fd5d36a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_weekday ymd(year{1234}, month{i}, weekday_indexed{});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp
index f66d6a083c4..7e8599e0509 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -71,4 +71,6 @@ int main()
         year_month_weekday ym{year{i}, January, weekday_indexed{Tuesday, 1}};
         assert((ym.ok() == year{i}.ok()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp
index 788af653555..e86e5b0fa6e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -70,4 +70,5 @@ int main()
     assert( year_month_weekday{sd} == ymwd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp
index 111cf5f38db..afb1d70148a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -70,4 +70,5 @@ int main()
     assert( year_month_weekday{sd} == ymwd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp
index 7e20a8eb05a..fd53279ddde 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -76,4 +76,6 @@ int main()
         assert(ymwd.weekday()  == Tuesday);
         assert(ymwd.index()    == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp
index 4deee9bc35d..cf229febe08 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -76,4 +76,6 @@ int main()
         assert(ymwd.weekday()  == Tuesday);
         assert(ymwd.index()    == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
index 1b9c8ad1041..dac1f7cc049 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday ymwd0(year{1234}, month{2}, weekday_indexed{weekday{i}, 1});
         assert(static_cast<unsigned>(ymwd0.weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
index 4a9832323f1..f089a8cb93e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -41,4 +41,6 @@ int main()
         assert( static_cast<unsigned>(ymwd1.weekday_indexed().weekday()) == 2);
         assert( static_cast<unsigned>(ymwd1.weekday_indexed().index()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp
index 8103c28aa60..1ead67570cf 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_weekday ym(year{i}, month{1}, weekday_indexed{});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp
index 847699b2516..5631127222b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -109,4 +109,6 @@ int main()
             year_month_weekday{year{i}, January, weekday_indexed{Tuesday, 1}},
             year_month_weekday{year{j}, January, weekday_indexed{Tuesday, 1}},
             i == j)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp
index ff472fdc6ce..47cfbea6a67 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp
@@ -50,7 +50,7 @@ constexpr bool testConstexprMonths ()
 }
 
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -96,4 +96,6 @@ int main()
         assert(ym1.index()   == 2);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp
index bc72d958ca0..29df4776e2b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp
@@ -51,7 +51,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_weekday ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -116,4 +116,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp
index eb92cf05e47..411e4335fd0 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp
@@ -45,7 +45,7 @@
 #include <iostream>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday = std::chrono::year_month_weekday;
     using year                = std::chrono::year;
@@ -53,4 +53,6 @@ int main()
     using weekday             = std::chrono::weekday;
 
     std::cout << year_month_weekday{year{2018}, month{3}, weekday{4}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp
index 449098c4f18..76e2e0f237e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday = std::chrono::year_month_weekday;
 
     static_assert(std::is_trivially_copyable_v<year_month_weekday>, "");
     static_assert(std::is_standard_layout_v<year_month_weekday>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp
index 1db6850dbce..31d2e9ca706 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -48,4 +48,6 @@ int main()
     static_assert( ym1.weekday_last() == weekday_last{Tuesday}, "");
     static_assert( ym1.ok(),                                    "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp
index 7b95084b214..df62d010ab6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday_last ymd(year{1234}, month{i}, weekday_last{weekday{}});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
index 1cffb4565b7..c18b926704c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -69,4 +69,6 @@ int main()
         year_month_weekday_last ym{year{i}, January, weekday_last{Tuesday}};
         assert((ym.ok() == year{i}.ok()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp
index 83f8b70dc79..c663406ee43 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month_day_last      = std::chrono::month_day_last;
@@ -57,4 +57,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+33)});
     }
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp
index cc3da2992e8..cb75842c64c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp
@@ -22,7 +22,7 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -65,4 +65,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+35)});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp
index ad513c5d0cf..b2bb1361b6b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -71,4 +71,6 @@ int main()
         assert(ymwd.year()     == y);
         assert(ymwd.weekday()  == Tuesday);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp
index 7d9255fe494..8ced182d6c8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -72,4 +72,6 @@ int main()
         assert(ymwd.month()    == January);
         assert(ymwd.weekday()  == Tuesday);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
index cc0521354f9..1de0b832309 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday_last ymwdl(year{1}, month{1}, weekday_last{weekday{i}});
         assert(static_cast<unsigned>(ymwdl.weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp
index 4011f0673ff..4e940791145 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday_last ymwdl(year{i}, month{1}, weekday_last{weekday{}});
         assert(static_cast<int>(ymwdl.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp
index a13b11f8c10..24074f33cbc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -110,4 +110,6 @@ int main()
             year_month_weekday_last{year{i}, January, weekday_last{Tuesday}},
             year_month_weekday_last{year{j}, January, weekday_last{Tuesday}},
             i == j)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp
index 20a58152f33..d58c461be8b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp
@@ -40,7 +40,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_weekday_last ym)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -89,4 +89,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp
index 45dd7562dc0..fe246cf42ba 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp
@@ -47,7 +47,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_weekday_last ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -112,4 +112,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp
index 6e4409c7138..cdfe55f1650 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday_last = std::chrono::year_month_weekday_last;
     using year                    = std::chrono::year;
@@ -34,4 +34,6 @@ int main()
     using weekday_last            = std::chrono::weekday_last;
 
     std::cout << year_month_weekday_last{year{2018}, month{3}, weekday_last{weekday{4}}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp
index e0580fac76f..70dea7bf922 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday_last = std::chrono::year_month_weekday_last;
 
     static_assert(std::is_trivially_copyable_v<year_month_weekday_last>, "");
     static_assert(std::is_standard_layout_v<year_month_weekday_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp
index 332d8163cb6..165bec2e117 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp
@@ -22,7 +22,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::file_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<C::time_point::clock, C>::value), "");
     static_assert(!C::is_steady, "");
     test(std::chrono::file_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp
index 75652f3ecd0..61d92381fc8 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp
@@ -21,8 +21,10 @@ void test() {
   ASSERT_SAME_TYPE(std::chrono::file_time<Dur>, std::chrono::time_point<std::chrono::file_clock, Dur>);
 }
 
-int main() {
+int main(int, char**) {
   test<std::chrono::nanoseconds>();
   test<std::chrono::minutes>();
   test<std::chrono::hours>();
+
+  return 0;
 }
\ No newline at end of file
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
index 3b51b91b501..79cdf06120c 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::file_clock C;
     ASSERT_NOEXCEPT(C::now());
@@ -31,4 +31,6 @@ int main()
     assert(t1.time_since_epoch().count() != 0);
     assert(C::time_point::min() < t1);
     assert(C::time_point::max() > t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp
index c36649a5d41..821072e6df6 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp
@@ -20,9 +20,11 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_signed<std::chrono::file_clock::rep>::value, "");
     assert(std::chrono::file_clock::duration::min() <
            std::chrono::file_clock::duration::zero());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
index 6f06e718e25..1650d3b6b5f 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
@@ -27,7 +27,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -35,4 +35,6 @@ int main()
     static_assert((std::is_same<C::duration, C::time_point::duration>::value), "");
     static_assert(C::is_steady || !C::is_steady, "");
     test(std::chrono::high_resolution_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
index c1d879c6f3b..ddf3ced87da 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
@@ -15,11 +15,13 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock C;
     C::time_point t1 = C::now();
     assert(t1.time_since_epoch().count() != 0);
     assert(C::time_point::min() < t1);
     assert(C::time_point::max() > t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
index 1577bc18008..0797f2cb5bc 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
@@ -29,7 +29,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::steady_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -37,4 +37,6 @@ int main()
     static_assert((std::is_same<C::duration, C::time_point::duration>::value), "");
     static_assert(C::is_steady, "");
     test(std::chrono::steady_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
index 248f1523f87..7d268fd67de 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
@@ -17,10 +17,12 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::steady_clock C;
     C::time_point t1 = C::now();
     C::time_point t2 = C::now();
     assert(t2 >= t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
index b15a8e2124d..b92652134ad 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
@@ -27,7 +27,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -36,4 +36,6 @@ int main()
     static_assert((std::is_same<C::time_point::clock, C>::value), "");
     static_assert((C::is_steady || !C::is_steady), "");
     test(std::chrono::system_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
index e6acef241c6..54252718d4a 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
@@ -15,9 +15,11 @@
 #include <chrono>
 #include <ctime>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     C::time_point t1 = C::from_time_t(C::to_time_t(C::now()));
     ((void)t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp
index 398cdb9d760..5802166c876 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using local_t = std::chrono::local_t;
     using year    = std::chrono::year;
@@ -61,4 +61,6 @@ int main()
     ASSERT_SAME_TYPE(decltype(s0.time_since_epoch()), seconds);
     assert( s0.time_since_epoch().count() == 0);
     assert( s1.time_since_epoch().count() == 946684800L);
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
index 00a163685f6..9d74541f989 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
@@ -15,11 +15,13 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     C::time_point t1 = C::now();
     assert(t1.time_since_epoch().count() != 0);
     assert(C::time_point::min() < t1);
     assert(C::time_point::max() > t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp
index cae8375d873..967af52e11d 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp
@@ -15,8 +15,10 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::system_clock::duration::min() <
            std::chrono::system_clock::duration::zero());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp
index 516f54914fd..174fbe94144 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using system_clock = std::chrono::system_clock;
     using year         = std::chrono::year;
@@ -60,4 +60,6 @@ int main()
     ASSERT_SAME_TYPE(decltype(s0.time_since_epoch()), seconds);
     assert( s0.time_since_epoch().count() == 0);
     assert( s1.time_since_epoch().count() == 946684800L);
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
index 0819a7b547f..86b37bb6bd1 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
@@ -15,9 +15,11 @@
 #include <chrono>
 #include <ctime>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     std::time_t t1 = C::to_time_t(C::now());
     ((void)t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp b/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp
index 92c015eef32..08870488c16 100644
--- a/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp
@@ -18,8 +18,10 @@
 #include <chrono>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::chrono::duration<int, std::ratio<1> >,
                    std::chrono::duration<int> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp b/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp
index 94e239c1f7c..02029c02bbe 100644
--- a/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp
@@ -15,8 +15,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<std::chrono::milliseconds> D;
     D d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp b/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp
index 6e78f776561..737576205cf 100644
--- a/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<int, std::ratio<5, -1> > D;
     D d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp b/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp
index 21873788a36..20298b772cb 100644
--- a/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp
@@ -22,8 +22,10 @@ public:
     static const int den = D;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<int, Ratio<1> > D;
     D d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp
index 6331dc95a9a..8d807c7a9b3 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp
@@ -20,7 +20,9 @@
 
 typedef std::chrono::duration<unsigned> unsigned_secs;
 
-int main()
+int main(int, char**)
 {
     std::chrono::abs(unsigned_secs(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp
index 5cb52ba7623..06f9a7c7f03 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp
@@ -30,7 +30,7 @@ test(const Duration& f, const Duration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::milliseconds( 7290000));
@@ -46,4 +46,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::abs(std::chrono::hours(3));
     static_assert(h2.count() == 3, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp
index 9d6566a082c..d0e47b7fa8d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h(3);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp
index 78beffe2617..084819af3ce 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h1(3);
@@ -38,4 +38,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
index 0b8f49fc38f..a9d136f792a 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::chrono::minutes m(3);
@@ -42,4 +42,6 @@ int main()
     static_assert( (std::is_same< decltype(zero+one), D1>::value), "");
     static_assert( (std::is_same< decltype(+one),     D1>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp
index 0e907b573b2..4247f2d5689 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s(3);
@@ -41,4 +41,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp
index c9f1278a376..cfdb7075b37 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h(3);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp
index 5abecee1648..4afb86e0caf 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h1(3);
@@ -39,4 +39,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
index f7ab6d2e299..fe065ff5f99 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::chrono::minutes m(3);
@@ -43,4 +43,6 @@ int main()
     static_assert( (std::is_same< decltype(-one),     D1>::value), "");
     static_assert( (std::is_same< decltype(+one),     D1>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp
index 1752d5257b8..b457619e154 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s(3);
@@ -41,4 +41,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp
index 4f79398f73b..753ea5a8bc1 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(15);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp
index 89b550d015c..649f4aa1a4c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::microseconds us1(11);
@@ -41,4 +41,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp
index 8ef16c7ff7c..0eb73ee674f 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::microseconds us(11);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp
index b4b76fb6f50..51c20c50764 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(3);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp
index e557bc21fb5..a9711f448c8 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::ceil<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp
index b509182c41e..a6e1982d044 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp
@@ -32,7 +32,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 3));
@@ -47,4 +47,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::ceil<std::chrono::hours>(std::chrono::milliseconds(-9000000));
     static_assert(h2.count() == -2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
index 5187d3d0e7c..4151756764a 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
@@ -32,7 +32,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test(std::chrono::milliseconds(7265000), std::chrono::hours(2));
     test(std::chrono::milliseconds(7265000), std::chrono::minutes(121));
@@ -50,4 +50,6 @@ int main()
     static_assert(h.count() == 2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp
index 62dd5a51d60..c119a800cfa 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::floor<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp
index 29142bdcf3e..6783b1f67ed 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp
@@ -31,7 +31,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -46,4 +46,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::floor<std::chrono::hours>(std::chrono::milliseconds(-9000000));
     static_assert(h2.count() == -3, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp
index aadfbfdc47e..93366b83618 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::round<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp
index b0789b7917d..ebd2e3194a4 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp
@@ -31,7 +31,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -46,4 +46,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::round<std::chrono::hours>(std::chrono::milliseconds(-9000000));
     static_assert(h2.count() == -2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp
index a46aa526bda..0f52c36d86c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp
@@ -18,7 +18,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration_cast<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
index 912d22fdf0e..c27b528017e 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -113,4 +113,6 @@ int main()
     static_assert(!(s1 != s2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
index 9eea6ceb3bd..de476357650 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
@@ -35,7 +35,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -151,4 +151,6 @@ int main()
     static_assert( (s1 >= s2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
index 0f6fb8d3590..4c0af92b23d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::milliseconds ms(1);
@@ -34,4 +34,6 @@ int main()
     static_assert(us.count() == 1000, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp
index b35c01c40ec..4311c1bde38 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp
@@ -17,8 +17,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<double> d;
     std::chrono::duration<int> i = d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp
index b66b2f3c601..fb0b488f7d8 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp
@@ -17,8 +17,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::microseconds us(1);
     std::chrono::milliseconds ms = us;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
index 5624327badc..f72c69c7ef1 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::duration<double, std::micro> us(1);
@@ -34,4 +34,6 @@ int main()
     static_assert(ms.count() == 1./1000, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
index a63471bc37d..fb127226a6c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::duration<int> i(3);
@@ -34,4 +34,6 @@ int main()
     static_assert(d.count() == 3000, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp
index 68484d1fb51..5b963f2b1f4 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp
@@ -26,11 +26,13 @@ void f(std::chrono::seconds)
     called = true;
 }
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::duration<int, std::exa> r(1);
     f(r);
     assert(called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp
index 9edcd46f902..c598afa3651 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp
@@ -32,7 +32,9 @@ test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
index f89263bf9b0..d1a808ba154 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
@@ -31,10 +31,12 @@ test(R r)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >(5);
     test<std::chrono::duration<int, std::ratio<3, 2> > >(5);
     test<std::chrono::duration<Rep, std::ratio<3, 2> > >(Rep(3));
     test<std::chrono::duration<double, std::ratio<2, 3> > >(5.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp
index fc6f5700a6a..f1e60f5e54d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp
@@ -19,7 +19,9 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<int> d = 1;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp
index bdbe7211b81..4a09325065c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp
@@ -19,7 +19,9 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d(1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
index 3ecb76135e1..1719b1302ba 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<double> d(5);
     assert(d.count() == 5);
@@ -28,4 +28,6 @@ int main()
     constexpr std::chrono::duration<double> d2(5);
     static_assert(d2.count() == 5, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp
index 831370994ee..6b4d0020379 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp
@@ -17,7 +17,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<int> d(1.);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp
index 13ad165b7bf..0d924f8f70b 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::chrono_literals;
 
@@ -57,4 +57,6 @@ int main()
     auto ns2 = 645.ns;
     assert ( ns == ns2 );
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp
index 025100c5928..97e29e87682 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp
@@ -11,8 +11,10 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::chrono::hours h  = 4h;  // should fail w/conversion operator not found
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp
index 9ca29086777..2e5b7bbb87b 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp
@@ -11,7 +11,7 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::chrono;
 
@@ -67,4 +67,6 @@ int main()
     assert(November  == month(11));
     assert(December  == month(12));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp
index 5c38db52713..dbc91559031 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp
@@ -11,9 +11,11 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using std::chrono::hours;
 
     hours foo  =  4h;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp
index 40709103254..d0b8b33e493 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp
@@ -13,7 +13,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals;
 
@@ -46,4 +46,6 @@ int main()
     assert ( ns == std::chrono::nanoseconds(645));
     auto ns2 = 645.ns;
     assert ( ns == ns2 );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
index 30aa62cd9d1..ad381f00565 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -71,4 +71,6 @@ int main()
     static_assert(r.count() == 75, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
index cb0a53fdf54..86ced3fbcbd 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -72,4 +72,6 @@ int main()
     static_assert(r.count() == -15, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
index 40f521bae01..e4190fe3385 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "truncate_fp.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns1(15);
@@ -65,4 +65,6 @@ int main()
     static_assert(s1 / s2 == 20./3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp
index 41c55fccaeb..327ff563567 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp
@@ -18,8 +18,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d(Rep(15));
     d = d / 5;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
index 8718ad75730..94da11302bf 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(15);
@@ -34,4 +34,6 @@ int main()
     static_assert(ns2.count() == 3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
index 7a2063ca54e..e7007c1fe35 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns1(15);
@@ -60,4 +60,6 @@ int main()
     static_assert(r.count() == 24, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp
index 3ee0578f805..f2a5885aba6 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp
@@ -18,8 +18,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d(Rep(15));
     d = d % 5;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
index 6d7e285d9b8..754b9800a7d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(15);
@@ -34,4 +34,6 @@ int main()
     static_assert(ns2.count() == 3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
index 19e33366f71..c3e49963808 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(3);
@@ -43,4 +43,6 @@ int main()
     static_assert(ns3.count() == 18, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp
index 6ad3c7928a9..44a77cea18a 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp
@@ -22,8 +22,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d;
     d = d * 5;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp
index 5cc717c5c04..9ce82582cf3 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp
@@ -22,8 +22,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d;
     d = 5 * d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
index c6f3f1e6547..58de66a0158 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
@@ -40,8 +40,10 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >();
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
index b16e608dcc7..9b0113b2980 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
@@ -40,8 +40,10 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >();
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
index f3065c30542..34a05b5f071 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
@@ -39,8 +39,10 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >();
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/types.pass.cpp b/libcxx/test/std/utilities/time/time.duration/types.pass.cpp
index 9e5abbc20a7..250e532859e 100644
--- a/libcxx/test/std/utilities/time/time.duration/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/types.pass.cpp
@@ -18,9 +18,11 @@
 #include <chrono>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<long, std::ratio<3, 2> > D;
     static_assert((std::is_same<D::rep, long>::value), "");
     static_assert((std::is_same<D::period, std::ratio<3, 2> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp b/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp
index e645e2970c6..8a58413a0aa 100644
--- a/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp
@@ -18,8 +18,10 @@
 #include <chrono>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::chrono::system_clock::duration,
                    std::chrono::time_point<std::chrono::system_clock>::duration>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/duration.fail.cpp b/libcxx/test/std/utilities/time/time.point/duration.fail.cpp
index a4881acc931..6461eb3d96f 100644
--- a/libcxx/test/std/utilities/time/time.point/duration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/duration.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::time_point<std::chrono::system_clock, int> T;
     T t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp
index 999071b72c6..002fffc3882 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool constexpr_test()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::chrono::system_clock Clock;
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(constexpr_test(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp
index 3d62cdedaac..2365d539ca7 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool constexpr_test()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::chrono::system_clock Clock;
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(constexpr_test(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp
index 4a90ec870cf..fb82fdffe4d 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::ceil<int>(std::chrono::system_clock::now());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp
index efd2a3e592b..8dfd1bdaa38 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp
@@ -49,7 +49,7 @@ void test_constexpr ()
 }
 
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 3));
@@ -65,4 +65,6 @@ int main()
 
     test_constexpr<std::chrono::milliseconds, 9000000, std::chrono::seconds, 9000> ();
     test_constexpr<std::chrono::milliseconds,-9000000, std::chrono::seconds,-9000> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp
index c5dfba6c4f1..12b1dec9fd5 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::floor<int>(std::chrono::system_clock::now());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp
index db2391d2518..d50fff4a1c8 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp
@@ -48,7 +48,7 @@ void test_constexpr ()
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -64,4 +64,6 @@ int main()
 
     test_constexpr<std::chrono::milliseconds, 9000000, std::chrono::seconds, 9000> ();
     test_constexpr<std::chrono::milliseconds,-9000000, std::chrono::seconds,-9000> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp
index 6c6f9c5bf5c..a5436c68404 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::round<int>(std::chrono::system_clock::now());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp
index e68e233969d..d8bb1b505b1 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp
@@ -48,7 +48,7 @@ void test_constexpr ()
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -64,4 +64,6 @@ int main()
 
     test_constexpr<std::chrono::milliseconds, 9000000, std::chrono::seconds, 9000> ();
     test_constexpr<std::chrono::milliseconds,-9000000, std::chrono::seconds,-9000> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp
index 5779ef9208a..90e6ccef666 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp
@@ -54,7 +54,7 @@ void test_constexpr ()
 
 #endif
 
-int main()
+int main(int, char**)
 {
     test(std::chrono::milliseconds(7265000), std::chrono::hours(2));
     test(std::chrono::milliseconds(7265000), std::chrono::minutes(121));
@@ -78,4 +78,6 @@ int main()
     test_constexpr<std::chrono::duration<int, std::ratio<2, 3>>, 9, T1, 10> ();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp
index 9e1f903b93f..c16492f730a 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp
@@ -18,10 +18,12 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::time_point<Clock, std::chrono::milliseconds> FromTimePoint;
     typedef std::chrono::time_point<Clock, std::chrono::minutes> ToTimePoint;
     std::chrono::time_point_cast<ToTimePoint>(FromTimePoint(std::chrono::milliseconds(3)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp
index e2b3508e000..2b5795026b3 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp
@@ -24,7 +24,7 @@
 
 #include "../../clock.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock1;
     typedef Clock                     Clock2;
@@ -36,4 +36,6 @@ int main()
     T1 t1(Duration1(3));
     T2 t2(Duration2(3000));
     t1 == t2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp
index cc2ef333763..f110ec5d406 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -82,4 +82,6 @@ int main()
     static_assert( (t1 != t2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp
index 04f7639d605..3d158ea890f 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp
@@ -32,7 +32,7 @@
 
 #include "../../clock.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock1;
     typedef Clock                     Clock2;
@@ -44,4 +44,6 @@ int main()
     T1 t1(Duration1(3));
     T2 t2(Duration2(3000));
     t1 < t2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp
index 57d24d08d02..3b4aa6abecf 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp
@@ -31,7 +31,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -106,4 +106,6 @@ int main()
     static_assert(!(t1 >= t2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp
index a68d4b0f304..2e601179a7d 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp
@@ -17,7 +17,7 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -26,4 +26,6 @@ int main()
     std::chrono::time_point<Clock, Duration2> t2(Duration2(3));
     std::chrono::time_point<Clock, Duration1> t1 = t2;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp
index 91bcebb1a91..f9b35c95738 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::microseconds Duration1;
@@ -35,4 +35,6 @@ int main()
     static_assert(t1.time_since_epoch() == Duration1(3000), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp
index 2deb8ae298c..b40113999a5 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::duration<Rep, std::milli> Duration;
@@ -32,4 +32,6 @@ int main()
     static_assert(t.time_since_epoch() == Duration::zero(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp
index 4a42eef3057..b28116236d0 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp
@@ -16,9 +16,11 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
     std::chrono::time_point<Clock, Duration> t = Duration(3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp
index 0830eea9119..078c6641e76 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
@@ -39,4 +39,6 @@ int main()
     static_assert(t.time_since_epoch() == Duration(3000), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp
index df6c691572e..7d78f7f4329 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -44,4 +44,6 @@ int main()
     static_assert(t3.time_since_epoch() == Duration2(3006), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp
index 876d42d560d..6fe8769695b 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp
@@ -30,7 +30,7 @@ void test2739()  // LWG2739
     assert(t1 < t0);
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -49,4 +49,6 @@ int main()
 #endif
     test2739<int32_t>();
     test2739<uint32_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp
index 851869d4d0d..22e4520f360 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -36,4 +36,6 @@ int main()
     static_assert((t1 - t2) == Duration2(2995), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp
index c8f2d41be97..e7826b1a610 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
@@ -27,4 +27,6 @@ int main()
     ASSERT_NOEXCEPT(       TP::max());
 #endif
     assert(TP::max() == TP(Duration::max()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp
index 1cac230624f..fae3339b03d 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
@@ -27,4 +27,6 @@ int main()
     ASSERT_NOEXCEPT(       TP::max());
 #endif
     assert(TP::min() == TP(Duration::min()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
index f44a7964f02..8d244c77346 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::duration_values<int>::max() ==
            std::numeric_limits<int>::max());
@@ -42,4 +42,6 @@ int main()
     ASSERT_NOEXCEPT(std::chrono::duration_values<double>::max());
     ASSERT_NOEXCEPT(std::chrono::duration_values<Rep>::max());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
index c64746d9fc7..4ff03c62286 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::duration_values<int>::min() ==
            std::numeric_limits<int>::lowest());
@@ -42,4 +42,6 @@ int main()
     ASSERT_NOEXCEPT(std::chrono::duration_values<double>::min());
     ASSERT_NOEXCEPT(std::chrono::duration_values<Rep>::min());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
index 6eec47ce3b0..d9de07b414e 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::duration_values<int>::zero() == 0);
     assert(std::chrono::duration_values<Rep>::zero() == 0);
@@ -31,4 +31,6 @@ int main()
     ASSERT_NOEXCEPT(std::chrono::duration_values<int>::zero());
     ASSERT_NOEXCEPT(std::chrono::duration_values<Rep>::zero());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp
index cf588f5c0af..9db3d96d26d 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp
@@ -29,7 +29,7 @@ test()
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<unsigned>();
@@ -39,4 +39,6 @@ int main()
     test<double>();
     test<long double>();
     test<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp
index 39afe6a5f53..3dde5404727 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert((std::is_same<Dc, De>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int, std::ratio<1, 100> >,
          std::chrono::duration<long, std::ratio<1, 1000> >,
@@ -38,4 +38,6 @@ int main()
     test<std::chrono::duration<double, std::ratio<21, 1> >,
          std::chrono::duration<short, std::ratio<15, 1> >,
          std::chrono::duration<double, std::ratio<3, 1> > >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp
index bf880fcd2b7..d73bb8ae6fd 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp
@@ -28,7 +28,7 @@ test()
     static_assert((std::is_same<Tc, Te>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int, std::ratio<1, 100> >,
          std::chrono::duration<long, std::ratio<1, 1000> >,
@@ -42,4 +42,6 @@ int main()
     test<std::chrono::duration<double, std::ratio<21, 1> >,
          std::chrono::duration<short, std::ratio<15, 1> >,
          std::chrono::duration<double, std::ratio<3, 1> > >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/weeks.pass.cpp b/libcxx/test/std/utilities/time/weeks.pass.cpp
index 2231c69550c..5a0cf3417f5 100644
--- a/libcxx/test/std/utilities/time/weeks.pass.cpp
+++ b/libcxx/test/std/utilities/time/weeks.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::weeks D;
     typedef D::rep Rep;
@@ -24,4 +24,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 22, "");
     static_assert(std::is_same_v<Period, std::ratio_multiply<std::ratio<7>, std::chrono::days::period>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/years.pass.cpp b/libcxx/test/std/utilities/time/years.pass.cpp
index c2229caee63..5016369268a 100644
--- a/libcxx/test/std/utilities/time/years.pass.cpp
+++ b/libcxx/test/std/utilities/time/years.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::years D;
     typedef D::rep Rep;
@@ -24,4 +24,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 17, "");
     static_assert(std::is_same_v<Period, std::ratio_multiply<std::ratio<146097, 400>, std::chrono::days::period>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
index d216c19fc54..5d0409a7ca3 100644
--- a/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
@@ -39,7 +39,7 @@ constexpr bool test_ignore_constexpr()
     return true;
 }
 
-int main() {
+int main(int, char**) {
     {
         constexpr auto& ignore_v = std::ignore;
         ((void)ignore_v);
@@ -50,4 +50,6 @@ int main() {
     {
         LIBCPP_STATIC_ASSERT(std::is_trivial<decltype(std::ignore)>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp
index 326d7bb589e..d57e7ad1825 100644
--- a/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp
@@ -15,7 +15,7 @@
 #include <tuple>
 #include <memory>
 
-int main () {
+int main(int, char**) {
     {
     std::tuple<std::unique_ptr<char>> up;
     std::tuple<std::shared_ptr<char>> sp;
@@ -29,4 +29,6 @@ int main () {
     // Smart pointers of type 'T[N]' are not tested here since they are not
     // supported by the standard nor by libc++'s implementation.
     // See https://reviews.llvm.org/D21320 for more information.
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp
index b9e6e111ca1..27f3d59349b 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp
@@ -25,11 +25,13 @@ struct X
     void operator()() {}
 };
 
-int main()
+int main(int, char**)
 {
     X x;
     std::function<void()> f(x);
+
+  return 0;
 }
 #else
-int main () {}
+int main(int, char**) { return 0; }
 #endif
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
index 2daef09fb08..52e94cc0b61 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
@@ -265,9 +265,11 @@ void test_return_type()
     test<13, int const volatile *>();
 }
 
-int main() {
+int main(int, char**) {
     test_constexpr_evaluation();
     test_call_quals_and_arg_types();
     test_return_type();
     test_noexcept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp
index 978c923ef0c..851a535eb49 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp
@@ -360,7 +360,7 @@ void test_ext_int_2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         test_ext_int_0<
@@ -422,4 +422,6 @@ int main()
           , std::tuple<A_base_2, int, int>, std::tuple<A_base_2 const, int, int>
           >();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp
index 138f074b243..004a5d46435 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp
@@ -129,7 +129,7 @@ void test_one()
     }
 }
 
-int main()
+int main(int, char**)
 {
     // Instantiate with 1-5 arguments.
     test_all<1>();
@@ -140,4 +140,6 @@ int main()
 
     // Stress test with 256
     test_one<256>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
index 6afd8882512..53574ee1d80 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
@@ -205,9 +205,11 @@ void test_noexcept() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_constexpr_construction();
     test_perfect_forwarding();
     test_noexcept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp
index bf4a8cc0dbb..9353add370f 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp
@@ -19,7 +19,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, char> T0;
@@ -30,4 +30,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1) == short('a'));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp
index e21118a2f55..8b9447c9900 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp
@@ -32,7 +32,7 @@ struct D
     explicit D(int i = 0) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -85,4 +85,6 @@ int main()
         assert(std::get<0>(t) == 43);
         assert(&std::get<0>(t) == &x);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp
index 95b1e2769de..71855a309c5 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp
@@ -43,7 +43,7 @@ struct E {
   }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -106,4 +106,6 @@ int main()
         assert(std::get<0>(t) == 43);
         assert(&std::get<0>(t) == &x);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp
index 167d442b726..c3fa6495ff7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp
@@ -19,7 +19,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<MoveOnly> T;
@@ -27,4 +27,6 @@ int main()
         T t;
         t = t0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp
index 5162c40533d..f6ff1041e5c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp
@@ -35,7 +35,7 @@ struct MoveAssignable {
   MoveAssignable& operator=(MoveAssignable&&) = default;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -100,4 +100,6 @@ int main()
         using T = std::tuple<int, MoveAssignable>;
         static_assert(!std::is_copy_assignable<T>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp
index 4545cf4df2b..575c3b1dfad 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp
@@ -48,7 +48,7 @@ int CountAssign::copied = 0;
 int CountAssign::moved = 0;
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -122,4 +122,6 @@ int main()
         assert(CountAssign::copied == 1);
         assert(CountAssign::moved == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp
index 2dec9fffae5..9681a238a9d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp
@@ -35,7 +35,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, std::unique_ptr<D>> T0;
@@ -46,4 +46,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1)->id_ == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
index 5e31090c9d5..5796e8dbe08 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
@@ -25,9 +25,11 @@
 typedef std::array<char, 1256> array_t;
 typedef std::tuple<array_t> tuple_t;
 
-int main()
+int main(int, char**)
 {
     array_t arr;
     tuple_t tup;
     tup = arr;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp
index b6e444c659f..973aa93df3c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp
@@ -131,7 +131,9 @@ void allocator_tests() {
 }
 
 
-int main() {
+int main(int, char**) {
   compile_tests();
   allocator_tests();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp
index 79064fb09c4..1e1b0846cc2 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp
@@ -78,7 +78,7 @@ struct ConvertibleFromInt {
   ConvertibleFromInt(int) : state(FromInt) {}
 };
 
-int main()
+int main(int, char**)
 {
     // Test for the creation of dangling references when a tuple is used to
     // store a reference to another tuple as its only element.
@@ -174,4 +174,6 @@ int main()
         std::tuple<VT> t2 = {t1};
         assert(std::get<0>(t2).state == VT::FromInt);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp
index 8992f7b8205..919d88e46a3 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp
@@ -57,7 +57,7 @@ struct ExplicitUnconstrainedCtor {
 
 };
 
-int main() {
+int main(int, char**) {
     typedef UnconstrainedCtor A;
     typedef ExplicitUnconstrainedCtor ExplicitA;
     {
@@ -94,4 +94,6 @@ int main() {
         std::tuple<ExplicitA&&> t2(std::forward_as_tuple(ExplicitA{}));
         ((void)t2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp
index 9f8658aa642..1493f4f8160 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp
@@ -29,7 +29,7 @@ extern IncompleteType inc2;
 IncompleteType const& cinc1 = inc1;
 IncompleteType const& cinc2 = inc2;
 
-int main() {
+int main(int, char**) {
     using IT = IncompleteType;
     { // try calling tuple(Tp const&...)
         using Tup = std::tuple<const IT&, const IT&>;
@@ -43,6 +43,8 @@ int main() {
         assert(&std::get<0>(t) == &inc1);
         assert(&std::get<1>(t) == &inc2);
     }
+
+  return 0;
 }
 
 struct IncompleteType {};
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp
index b0dd392f171..6c44f7027ee 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp
@@ -44,7 +44,7 @@ struct ExplicitDerived : std::tuple<T> {
   explicit operator std::tuple<U>() && { ++count; return {}; }
 };
 
-int main() {
+int main(int, char**) {
   {
     std::tuple<Explicit> foo = Derived<int>{42}; ((void)foo);
     assert(count == 1);
@@ -84,4 +84,6 @@ int main() {
   }
   count = 0;
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp
index 3a0e0f888e9..3b9d0beead9 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp
@@ -42,9 +42,11 @@ public:
     bool operator< (const MoveOnly& x) const {return data_ <  x.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<MoveOnly> t = 1;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp
index f43e6d8bced..916255c967a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp
@@ -102,7 +102,7 @@ void test_default_constructible_extension_sfinae()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<MoveOnly> t(MoveOnly(0));
@@ -156,4 +156,6 @@ int main()
     // Check that SFINAE is properly applied with the default reduced arity
     // constructor extensions.
     test_default_constructible_extension_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp
index e4ed4769002..c5f52a92846 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp
@@ -39,7 +39,7 @@ struct NonDefaultConstructible {
 
 struct DerivedFromAllocArgT : std::allocator_arg_t {};
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<> t(std::allocator_arg, A1<int>());
@@ -105,4 +105,6 @@ int main()
         std::tuple<T, T> t2(42, 42);
         (void)t2;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp
index 99155823b3a..57e2f1b4188 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp
@@ -77,7 +77,7 @@ struct Explicit {
   explicit Explicit(int x) : value(x) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<Explicit> t{std::allocator_arg, std::allocator<void>{}, 42};
@@ -148,4 +148,6 @@ int main()
     // ensure that the "reduced-arity-initialization" extension is not offered
     // for these constructors.
     test_uses_allocator_sfinae_evaluation();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp
index 1759ba4f3c4..76f99e1978d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp
@@ -35,8 +35,10 @@ std::tuple<ExplicitCopy> non_const_explicity_copy_test() {
     return {std::allocator_arg, std::allocator<void>{}, e};
     // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
 }
-int main()
+int main(int, char**)
 {
     const_explicit_copy_test();
     non_const_explicity_copy_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp
index 10647a49d14..3b5b27f7b15 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp
@@ -40,7 +40,7 @@ std::tuple<ImplicitCopy> testImplicitCopy2() {
     return {std::allocator_arg, std::allocator<void>{}, i};
 }
 
-int main()
+int main(int, char**)
 {
     {
         // check that the literal '0' can implicitly initialize a stored pointer.
@@ -94,4 +94,6 @@ int main()
         assert(!alloc_last::allocator_constructed);
         assert(std::get<2>(t) == alloc_last(3));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp
index baafee879f9..a7cffa72db6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp
@@ -23,7 +23,7 @@
 #include "../alloc_first.h"
 #include "../alloc_last.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, int> T0;
@@ -55,4 +55,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1) == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp
index 8d0482859a0..ca9518d6b2b 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp
@@ -36,7 +36,9 @@ std::tuple<ExplicitCopy> non_const_explicit_copy_test() {
     // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
 }
 
-int main()
+int main(int, char**)
 {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp
index bcece609830..083e15797f6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp
@@ -33,7 +33,7 @@ struct Implicit {
   Implicit(int x) : value(x) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -86,4 +86,6 @@ int main()
         std::tuple<Implicit> t2 = {std::allocator_arg, std::allocator<void>{}, t1};
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp
index ed485c90107..7a2a5ffff5d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp
@@ -29,7 +29,9 @@ std::tuple<ExplicitCopy> explicit_move_test() {
     // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
 }
 
-int main()
+int main(int, char**)
 {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp
index e86ec8aea92..1f33ef2fc6e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp
@@ -49,7 +49,7 @@ struct Implicit {
   Implicit(int x) : value(x) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<int> T0;
@@ -100,4 +100,6 @@ int main()
         std::tuple<Implicit> t2 = {std::allocator_arg, std::allocator<void>{}, std::move(t1)};
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp
index 19829a967bb..1db842b8d91 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp
@@ -22,7 +22,7 @@
 #include "../alloc_first.h"
 #include "../alloc_last.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -77,4 +77,6 @@ int main()
         assert(std::get<2>(t) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp
index c77484de54b..fc25a4fc6a4 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp
@@ -23,7 +23,7 @@
 #include "../alloc_first.h"
 #include "../alloc_last.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -76,4 +76,6 @@ int main()
         assert(std::get<2>(t) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp
index 3da2d8a466d..e45702d88b7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp
@@ -39,7 +39,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, std::unique_ptr<D>> T0;
@@ -51,4 +51,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1)->id_ == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp
index 2a405c1a4af..bb7c5573505 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp
@@ -42,6 +42,8 @@ std::tuple<ExplicitCopy> const_explicit_copy_no_brace() {
     // expected-error@-1 {{no viable conversion}}
 }
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp
index 955a83a6e88..d4c29c93c37 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp
@@ -76,7 +76,7 @@ std::tuple<ImplicitCopy> testImplicitCopy3() {
     return i;
 }
 
-int main()
+int main(int, char**)
 {
     {
         // check that the literal '0' can implicitly initialize a stored pointer.
@@ -159,4 +159,6 @@ int main()
         assert(std::get<3>(t) == 0.0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp
index 35e82277f8d..8804c27b8a2 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp
@@ -18,9 +18,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<int, char*, std::string, double&> t(2, nullptr, "text");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
index 0fd29b22fd7..bbe51e39254 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, char> T0;
@@ -42,4 +42,6 @@ int main()
         static_assert(std::get<1>(t1) == short('a'), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
index 98d002b8042..41f73328ab7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
@@ -64,7 +64,7 @@ struct C
 
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -136,4 +136,6 @@ int main()
         std::tuple<Implicit> t2 = t1;
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp
index 79332841eb8..071f13cf913 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp
@@ -44,7 +44,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -100,4 +100,6 @@ int main()
         std::tuple<Implicit> t2 = std::move(t1);
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp
index f82dc6b1ff2..7eeb65a8fdd 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp
@@ -19,11 +19,13 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<MoveOnly> T;
         T t0(MoveOnly(2));
         T t = t0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp
index 7c581cb7714..01278130400 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp
@@ -22,7 +22,7 @@
 
 struct Empty {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -66,4 +66,6 @@ int main()
         ((void)e); // Prevent unused warning
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp
index 15bcde7e973..ae296f73945 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp
@@ -44,7 +44,7 @@ struct IllFormedDefault {
     int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<> t;
@@ -106,4 +106,6 @@ int main()
         IllFormedDefault v(0);
         std::tuple<IllFormedDefault> t(v);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp
index 1d4779aae36..80b09b87180 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp
@@ -23,7 +23,7 @@
 #include <cassert>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
   static_assert(std::is_trivially_destructible<
       std::tuple<> >::value, "");
@@ -35,4 +35,6 @@ int main()
       std::tuple<std::string> >::value, "");
   static_assert(!std::is_trivially_destructible<
       std::tuple<int, std::string> >::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp
index ea393abafe4..3ff089a0b31 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp
@@ -149,7 +149,9 @@ void test_empty_specialization()
   }
 }
 
-int main() {
+int main(int, char**) {
   test_primary_template();
   test_empty_specialization();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp
index 98a12a972f8..977dc4c3264 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp
@@ -80,7 +80,7 @@ void test_sfinae() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -121,4 +121,6 @@ int main()
         test_sfinae<move_only_ebo>();
         test_sfinae<move_only_large>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp
index 3953ee150a2..635be614b9a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp
@@ -34,7 +34,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, std::unique_ptr<D>> T0;
@@ -44,4 +44,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1)->id_ == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp
index 24868515643..bdbe4fc4b44 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp
@@ -95,7 +95,9 @@ void test_const_Types_lazy_sfinae()
     assert(std::get<0>(t).value == 42);
 }
 
-int main() {
+int main(int, char**) {
     test_tuple_like_lazy_sfinae();
     test_const_Types_lazy_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
index b84dba37899..2f9447f2a7d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
@@ -28,8 +28,10 @@
 typedef std::array<char, 1256> array_t;
 typedef std::tuple<array_t> tuple_t;
 
-int main()
+int main(int, char**)
 {
     array_t arr;
     tuple_t tup(arr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp
index 5a7940da656..8dc1e48f867 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp
@@ -64,7 +64,7 @@ test3(const Tuple&)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         test0(std::forward_as_tuple());
@@ -84,4 +84,6 @@ int main()
         static_assert ( test3 (std::forward_as_tuple(i, c)) == 2, "" );
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp
index 3f0dae093f0..444e978b01e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         int i = 0;
@@ -50,4 +50,6 @@ int main()
         static_assert (d1 == 3.14, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
index f703ef2c849..53ccc23b97c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
@@ -39,7 +39,7 @@ constexpr bool test_tie_constexpr() {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         int i = 0;
@@ -60,4 +60,6 @@ int main()
         static_assert(test_tie_constexpr(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
index 927fc2ab891..40efbd1b801 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<> t = std::tuple_cat();
@@ -238,4 +238,6 @@ int main()
         );
         assert(t2 == std::make_tuple(std::make_tuple(1), std::make_tuple(2)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp
index 4c0b5a6b460..650303ff7b2 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp
@@ -20,7 +20,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<double&, std::string, int> T;
@@ -37,4 +37,6 @@ int main()
 
         std::get<1>(t) = "four";
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp
index 5ca0bd8e963..a280c500ba5 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp
@@ -24,7 +24,7 @@
 
 struct Empty {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<int> T;
@@ -64,4 +64,6 @@ int main()
         assert(std::get<2>(t) == 5);
         assert(d == 2.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp
index 373d84bad99..cf0e88246d3 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp
@@ -23,11 +23,13 @@ template <class T> void cref(T const&&) = delete;
 
 std::tuple<int> const tup4() { return std::make_tuple(4); }
 
-int main()
+int main(int, char**)
 {
     // LWG2485: tuple should not open a hole in the type system, get() should
     // imitate [expr.ref]'s rules for accessing data members
     {
         cref(std::get<0>(tup4()));  // expected-error {{call to deleted function 'cref'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp
index 4c2654cd735..5801d5a5e65 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::tuple<int> T;
@@ -76,4 +76,6 @@ int main()
     static_assert(std::get<1>(std::move(t)) == 5, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp
index 3708e5cb0ca..3cbf01b25f8 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp
@@ -36,7 +36,7 @@ struct S {
 constexpr std::tuple<int, int> getP () { return { 3, 4 }; }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<int> T;
@@ -81,4 +81,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp
index 114672b7c7a..ae968403b01 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp
@@ -21,7 +21,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<std::unique_ptr<int> > T;
@@ -29,4 +29,6 @@ int main()
         std::unique_ptr<int> p = std::get<0>(std::move(t));
         assert(*p == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp
index f85c8098f7d..51bf1d550cd 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp
@@ -31,8 +31,10 @@ void test_bad_return_type() {
     upint p = std::get<upint>(t); // expected-error{{deleted copy constructor}}
 }
 
-int main()
+int main(int, char**)
 {
     test_bad_index();
     test_bad_return_type();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp
index 9df8ce381a7..7dd4e8f10ad 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     {
@@ -90,4 +90,6 @@ int main()
     static_assert(std::get<int>(std::move(t)) == 1, "");
     static_assert(std::get<const int>(std::move(t)) == 2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp
index e56f86a1cca..a97e60ca779 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp
@@ -40,7 +40,7 @@ void test()
     static_assert((std::is_same<typename std::tuple_element<idx, const volatile T>::type, const volatile U>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::array<int, 5>, 5, int, 0>();
     test<std::array<int, 5>, 5, int, 1>();
@@ -48,4 +48,6 @@ int main()
     test<std::array<volatile int, 4>, 4, volatile int, 3>();
     test<std::array<char *, 3>, 3, char *, 1>();
     test<std::array<char *, 3>, 3, char *, 2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp
index eb1704c943b..fdfb8b8b0a8 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp
@@ -38,7 +38,7 @@ void test()
     static_assert((std::is_same<typename std::tuple_element<idx, const volatile T>::type, const volatile U>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::pair<int, int>, 2, int, 0>();
     test<std::pair<int, int>, 2, int, 1>();
@@ -46,4 +46,6 @@ int main()
     test<std::pair<int, volatile int>, 2, volatile int, 1>();
     test<std::pair<char *, int>, 2, char *, 0>();
     test<std::pair<char *, int>, 2, int,    1>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp
index a1c42921ba2..24b735b7e68 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp
@@ -22,7 +22,7 @@
 #include <tuple>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     using T =  std::tuple<int, long, void*>;
     using E1 = typename std::tuple_element<1, T &>::type; // expected-error{{undefined template}}
@@ -30,4 +30,6 @@ int main()
     using E3 = typename std::tuple_element<4, T const>::type;
         // expected-error@__tuple:* 2 {{static_assert failed}}
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
index ecb6ea087ef..5ad2b08220e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
@@ -39,7 +39,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::tuple<int>, 0, int>();
     test<std::tuple<char, int>, 0, char>();
@@ -47,4 +47,6 @@ int main()
     test<std::tuple<int*, char, int>, 0, int*>();
     test<std::tuple<int*, char, int>, 1, char>();
     test<std::tuple<int*, char, int>, 2, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
index aa20818393b..9b065b3b9f6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
@@ -18,9 +18,11 @@
 
 #include <tuple>
 
-int main()
+int main(int, char**)
 {
     (void)std::tuple_size<std::tuple<> &>::value; // expected-error {{implicit instantiation of undefined template}}
     (void)std::tuple_size<int>::value; // expected-error {{implicit instantiation of undefined template}}
     (void)std::tuple_size<std::tuple<>*>::value; // expected-error {{implicit instantiation of undefined template}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
index 2a602b1ca26..f27c7eb470a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
@@ -32,10 +32,12 @@ void test()
                                    std::tuple_size<const volatile T> >::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::tuple<>, 0>();
     test<std::tuple<int>, 1>();
     test<std::tuple<char, int>, 2>();
     test<std::tuple<char, char*, int>, 3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp
index 3d092506828..83b773abf22 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp
@@ -39,7 +39,7 @@ public:
 template <>
 struct std::tuple_size<Dummy3> {};
 
-int main()
+int main(int, char**)
 {
   // Test that tuple_size<const T> is not incomplete when tuple_size<T>::value
   // is well-formed but not a constant expression.
@@ -59,4 +59,6 @@ int main()
     // expected-error@__tuple:* 1 {{no member named 'value'}}
     (void)std::tuple_size<const Dummy3>::value; // expected-note {{here}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp
index 44e100c6d36..32bad3317bc 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp
@@ -50,7 +50,7 @@ void test_incomplete() {
 }
 
 
-int main()
+int main(int, char**)
 {
   test_complete<std::tuple<> >();
   test_complete<std::tuple<int&> >();
@@ -63,4 +63,6 @@ int main()
   test_incomplete<int>();
   test_incomplete<std::tuple<int>&>();
   test_incomplete<Dummy2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp
index f191f9f64d7..00f7ff26972 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp
@@ -139,11 +139,13 @@ void test_after_tuple_size_specialization() {
   assert(p == -1);
 }
 
-int main() {
+int main(int, char**) {
   test_decomp_user_type();
   test_decomp_tuple();
   test_decomp_pair();
   test_decomp_array();
   test_before_tuple_size_specialization();
   test_after_tuple_size_specialization();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
index 820cb0443f8..8bd3fbd579e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
@@ -16,10 +16,12 @@
 
 #include <tuple>
 
-int main()
+int main(int, char**)
 {
     (void)std::tuple_size_v<std::tuple<> &>; // expected-note {{requested here}}
     (void)std::tuple_size_v<int>; // expected-note {{requested here}}
     (void)std::tuple_size_v<std::tuple<>*>; // expected-note {{requested here}}
     // expected-error@tuple:* 3 {{implicit instantiation of undefined template}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp
index b2b3e72b9be..bd01f49497c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp
@@ -26,7 +26,7 @@ void test()
     static_assert(std::tuple_size_v<Tuple const volatile> == std::tuple_size<Tuple>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::tuple<>, 0>();
 
@@ -39,4 +39,6 @@ int main()
 
     test<std::tuple<int, int, int>, 3>();
     test<std::array<int, 3>, 3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp
index 9c00418768f..2efbfa50e15 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp
@@ -27,7 +27,7 @@ template <class T> constexpr bool has_value() { return has_value<T>(0); }
 
 struct Dummy {};
 
-int main() {
+int main(int, char**) {
   // Test that the ::value member does not exist
   static_assert(has_value<std::tuple<int> const>(), "");
   static_assert(has_value<std::pair<int, long> volatile>(), "");
@@ -35,4 +35,6 @@ int main() {
   static_assert(!has_value<const int>(), "");
   static_assert(!has_value<volatile void>(), "");
   static_assert(!has_value<const volatile std::tuple<int>&>(), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
index 709f747c744..0302c839e74 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T1;
@@ -154,4 +154,6 @@ int main()
         static_assert(t1 != t2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp
index 9f29c6c4a1b..64ed9b4a90e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp
@@ -34,7 +34,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T1;
@@ -208,4 +208,6 @@ int main()
         static_assert(!(t1 >= t2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp
index 079977016b8..eee8f18196a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -58,4 +58,6 @@ int main()
         assert(std::get<1>(t1) == 1);
         assert(std::get<2>(t1) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp
index 097f69b42ea..951a8872609 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -57,4 +57,6 @@ int main()
         assert(std::get<1>(t1) == 1);
         assert(std::get<2>(t1) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp
index 5e4722874af..b04c491ede6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp
@@ -20,7 +20,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -42,4 +42,6 @@ int main()
         static_assert((std::is_base_of<std::true_type,
                                        std::uses_allocator<T, A>>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
index daa287e3e01..710b33878d9 100644
--- a/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp
index 139847fdae5..8192a9020f7 100644
--- a/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::hash<std::type_index> H;
     static_assert((std::is_same<typename H::argument_type, std::type_index>::value), "" );
@@ -29,4 +29,6 @@ int main()
 
     std::type_index t1 = typeid(int);
     assert(std::hash<std::type_index>()(t1) == t1.hash_code());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp
index cafeebb0930..c133130f10e 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp
@@ -16,9 +16,11 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_info const & info = typeid(int);
     std::type_index t1(info);
     assert(t1.name() == info.name());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp
index 210d0ab028c..97f6448b73e 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp
@@ -16,11 +16,13 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1 = typeid(int);
     std::type_index t2 = typeid(int);
     std::type_index t3 = typeid(long);
     assert(t1 == t2);
     assert(t1 != t3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp
index f5b6cc35c7d..0619ff75443 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp
@@ -15,9 +15,11 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::type_info& ti = typeid(int);
     std::type_index t1 = typeid(int);
     assert(t1.hash_code() == ti.hash_code());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp
index 1f631b7b997..e24b3975e66 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp
@@ -18,7 +18,7 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1 = typeid(int);
     std::type_index t2 = typeid(int);
@@ -41,4 +41,6 @@ int main()
         assert( (t1 >  t3));
         assert( (t1 >= t3));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp
index 1b01f52f9f7..ee91629b35c 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp
@@ -16,9 +16,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::type_info& ti = typeid(int);
     std::type_index t1 = typeid(int);
     assert(std::string(t1.name()) == ti.name());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp
index b7fbb6f91cf..72cae39d045 100644
--- a/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp
@@ -15,11 +15,13 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1(typeid(int));
     std::type_index t2(typeid(double));
     assert(t2 != t1);
     t2 = t1;
     assert(t2 == t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp
index 9520cd8f67e..df0df2e8c92 100644
--- a/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp
@@ -15,9 +15,11 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1(typeid(int));
     std::type_index t2 = t1;
     assert(t2 == t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp
index 333e04b1811..e8ce292cca0 100644
--- a/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp
@@ -22,7 +22,7 @@
 #include "poisoned_hash_helper.hpp"
 #endif
 
-int main()
+int main(int, char**)
 {
   {
     typedef std::hash<std::type_index> H;
@@ -34,4 +34,6 @@ int main()
     test_hash_enabled_for_type<std::type_index>(std::type_index(typeid(int)));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp b/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp
index 5f3b78b7245..1bb2e64c371 100644
--- a/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp
+++ b/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp
@@ -15,7 +15,9 @@
 
 struct S {int i;};
 
-int main()
+int main(int, char**)
 {
     std::as_const(S{});
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp b/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp
index 284e5b7b3d6..32d240a0b41 100644
--- a/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp
+++ b/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp
@@ -34,7 +34,7 @@ void test(T& t)
     assert(std::as_const<const volatile T>(t) == t);
 }
 
-int main()
+int main(int, char**)
 {
     int i = 3;
     double d = 4.0;
@@ -42,4 +42,6 @@ int main()
     test(i);
     test(d);
     test(s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/declval/declval.pass.cpp b/libcxx/test/std/utilities/utility/declval/declval.pass.cpp
index b298d58a018..6509fd4377c 100644
--- a/libcxx/test/std/utilities/utility/declval/declval.pass.cpp
+++ b/libcxx/test/std/utilities/utility/declval/declval.pass.cpp
@@ -21,11 +21,13 @@ class A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<decltype(std::declval<A>()), A&&>::value), "");
 #else
     static_assert((std::is_same<decltype(std::declval<A>()), A&>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp b/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp
index 1defcbfb339..41e8abb43e5 100644
--- a/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp
+++ b/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp
@@ -39,7 +39,7 @@ TEST_CONSTEXPR bool test_constexpr() {
 
 
 
-int main()
+int main(int, char**)
 {
     {
     int v = 12;
@@ -80,4 +80,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/forward.fail.cpp b/libcxx/test/std/utilities/utility/forward/forward.fail.cpp
index a689b1d0dfe..4efc1b6aad1 100644
--- a/libcxx/test/std/utilities/utility/forward/forward.fail.cpp
+++ b/libcxx/test/std/utilities/utility/forward/forward.fail.cpp
@@ -19,7 +19,7 @@ struct A
 A source() {return A();}
 const A csource() {return A();}
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -49,4 +49,6 @@ int main()
         A a;
         std::forward(a); // expected-error {{no matching function for call to 'forward'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/forward.pass.cpp b/libcxx/test/std/utilities/utility/forward/forward.pass.cpp
index 394c016e2c3..b2f7c960392 100644
--- a/libcxx/test/std/utilities/utility/forward/forward.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/forward.pass.cpp
@@ -41,7 +41,7 @@ constexpr bool test_constexpr_forward() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     A a;
     const A ca = A();
@@ -87,4 +87,6 @@ int main()
     static_assert(std::forward<const int&>(i2) == 42, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp b/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp
index c5a2507a750..522382dc7ed 100644
--- a/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp
@@ -28,7 +28,7 @@ struct eight {one _[8];};
 one test(A&);
 two test(const A&);
 
-int main()
+int main(int, char**)
 {
     A a;
     const A ca = A();
@@ -54,4 +54,6 @@ int main()
     static_assert(sizeof(test(std::forward<const A>(ca))) == 2, "");
     static_assert(sizeof(test(std::forward<const A>(csource()))) == 2, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/move.fail.cpp b/libcxx/test/std/utilities/utility/forward/move.fail.cpp
index bd8fd46a97e..86f3cc3e5d0 100644
--- a/libcxx/test/std/utilities/utility/forward/move.fail.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move.fail.cpp
@@ -24,10 +24,12 @@ const move_only csource() {return move_only();}
 
 void test(move_only) {}
 
-int main()
+int main(int, char**)
 {
     move_only a;
     const move_only ca = move_only();
 
     test(std::move(ca)); // c
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/move.pass.cpp b/libcxx/test/std/utilities/utility/forward/move.pass.cpp
index c98efa1c345..3db61cda27d 100644
--- a/libcxx/test/std/utilities/utility/forward/move.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move.pass.cpp
@@ -62,7 +62,7 @@ constexpr bool test_constexpr_move() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     { // Test return type and noexcept.
         static_assert(std::is_same<decltype(std::move(x)), int&&>::value, "");
@@ -117,4 +117,6 @@ int main()
         static_assert(std::move(y) == 42, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp b/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp
index 52a276c2412..11ea3c58f09 100644
--- a/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp
@@ -39,7 +39,7 @@ struct legacy
     legacy(const legacy&);
 };
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     const int ci = 0;
@@ -71,4 +71,6 @@ int main()
     static_assert(i2 == 23, "" );
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp b/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp
index 9c8dbedcc65..42e80866562 100644
--- a/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp
+++ b/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp
@@ -32,7 +32,7 @@ operator < (const A& x, const A& y)
     return x.data_ < y.data_;
 }
 
-int main()
+int main(int, char**)
 {
     using namespace std::rel_ops;
     A a1(1);
@@ -45,4 +45,6 @@ int main()
     assert(a1 <= a2);
     assert(a2 >= a2);
     assert(a2 >= a1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp
index e14a1c46a7b..e186514f0ea 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp
@@ -17,7 +17,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -26,4 +26,6 @@ int main()
         assert(std::get<1>(p) == 4);
         std::get<0>(p) = 5;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
index 2b164deb457..d9747b337e8 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -36,4 +36,6 @@ int main()
         static_assert(std::get<1>(p1) == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp
index 05c81a23b58..a477c5150ab 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<std::unique_ptr<int>, short> P;
@@ -62,4 +62,6 @@ int main()
     static_assert(std::get<1>(std::move(p1)) == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp
index 45fb7aa7942..6119cd5c8ce 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp
@@ -29,7 +29,7 @@ struct S {
 constexpr std::pair<int, int> getP () { return { 3, 4 }; }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -49,4 +49,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp
index 9ca7b4df6df..e0ce55bba90 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp
@@ -20,7 +20,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<int>, short> P;
@@ -28,4 +28,6 @@ int main()
         std::unique_ptr<int> ptr = std::get<0>(std::move(p));
         assert(*ptr == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp
index 99fb2cd2259..f2d3359e7a5 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp
@@ -16,7 +16,7 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     {
@@ -81,4 +81,6 @@ int main()
     static_assert(std::get<int>(std::move(p)) == 1, "");
     static_assert(std::get<const int>(std::move(p)) == 2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp
index bba71cb8de2..dce209921b8 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp
@@ -12,9 +12,11 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     auto t1 = std::make_pair<int, double> ( 42, 3.4 );
     assert (( std::get<cf>(t1) == cf {1,2} ));  // no such type
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp
index c79e0788ce0..4c2ea88e6b8 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp
@@ -12,9 +12,11 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     auto t1 = std::make_pair<int, int> ( 42, 43 );
     assert ( std::get<int>(t1) == 42 ); // two ints
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp
index 4787d0e2edd..e30b787e1fd 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp
@@ -12,9 +12,11 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::unique_ptr<int> upint;
     std::pair<upint, int> t(upint(new int(4)), 23);
     upint p = std::get<upint>(t);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
index ba571fda1eb..e53ca898d26 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <utility>
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<int, short> T;
     std::tuple_element<2, T>::type foo; // expected-error@utility:* {{Index out of bounds in std::tuple_element<std::pair<T1, T2>>}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp
index 4ba58143442..1e41e3fda5d 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp
@@ -47,8 +47,10 @@ void test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<int, short>();
     test<int*, char>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp
index a88b8459692..3b95b4749dd 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <utility>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -32,4 +32,6 @@ int main()
         typedef std::pair<int, short> const volatile P1;
         static_assert((std::tuple_size<P1>::value == 2), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp
index 72eb312081e..98f864caf1f 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp
@@ -41,7 +41,7 @@ public:
     unsigned get_u2() const {return u2_;}
 };
 
-int main()
+int main(int, char**)
 {
     std::pair<A, B> p(std::piecewise_construct,
                       std::make_tuple(4, 'a'),
@@ -51,4 +51,6 @@ int main()
     assert(p.second.get_d() == 3.5);
     assert(p.second.get_u1() == 6u);
     assert(p.second.get_u2() == 2u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp
index 11403c91de0..0f22808de48 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp
@@ -46,7 +46,7 @@ struct ImplicitT {
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<int>, short*> P;
@@ -96,4 +96,6 @@ int main()
         static_assert(p.second.value == 43, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp
index 5af432b991a..834d73dd7f5 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp
@@ -20,7 +20,7 @@
 #include "archetypes.hpp"
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -48,4 +48,6 @@ int main()
        assert(p.second.value == -42);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
index db671a1501a..f4dfe5e1b94 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
@@ -49,7 +49,7 @@ int CountAssign::moved = 0;
 struct Incomplete;
 extern Incomplete inc_obj;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<CopyAssignable, short> P;
@@ -94,6 +94,8 @@ int main()
         P p(42, inc_obj);
         assert(&p.second == &inc_obj);
     }
+
+  return 0;
 }
 
 struct Incomplete {};
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
index 53cc49183f7..47f85eaa6b4 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
@@ -27,7 +27,7 @@ private:
 struct Incomplete;
 extern Incomplete inc_obj;
 
-int main()
+int main(int, char**)
 {
     {
     // Test that we don't constrain the assignment operator in C++03 mode.
@@ -42,6 +42,8 @@ int main()
     P p(42, inc_obj);
     assert(&p.second == &inc_obj);
     }
+
+  return 0;
 }
 
 struct Incomplete {};
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
index 91427ca7f2c..b4f0c01094d 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
@@ -45,7 +45,7 @@ struct CountAssign {
 int CountAssign::copied = 0;
 int CountAssign::moved = 0;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<int>, int> P;
@@ -92,4 +92,6 @@ int main()
         assert(CountAssign::moved == 1);
         assert(CountAssign::copied == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp
index 7248c2ffa02..0be0a4e9526 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp
@@ -29,7 +29,7 @@ struct Derived
 {
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<Derived>, short> P1;
@@ -55,4 +55,6 @@ int main()
        assert(p.first == 42);
        assert(p.second.value == -42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp
index fcaa44849cb..e147d755856 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp
@@ -46,7 +46,7 @@ void test_sfinae() {
     static_assert(test_convertible<P2,   T2,   T1Arg>() == CanConvert, "");
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<float, short*> P;
@@ -94,4 +94,6 @@ int main()
         static_assert(p.second == 10, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp
index 4759303d663..880179723fb 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp
@@ -24,7 +24,7 @@ public:
     bool operator==(const A& a) const {return data_ == a.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<float, short*> P;
@@ -38,4 +38,6 @@ int main()
         assert(p.first == A(1));
         assert(p.second == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp
index c9c733d8cbe..ce1e86c1a8b 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp
@@ -53,7 +53,7 @@ struct ImplicitT {
   int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, int> P1;
@@ -177,4 +177,6 @@ int main()
         static_assert(p2.second.value == 101, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp
index 8a3fca758eb..9f6498806f3 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp
@@ -15,7 +15,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -25,4 +25,6 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp
index bee96000e52..81a32901abe 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -35,4 +35,6 @@ int main()
         static_assert(p2.second == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp
index b3a248c8862..70557aa923c 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp
@@ -139,7 +139,7 @@ void test_illformed_default()
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         // Check that pair<T, U> can still be used even if
@@ -160,4 +160,6 @@ int main()
         test_is_default_constructible<int>();
         test_is_default_constructible<DefaultSFINAES<int>>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp
index 9a07814b123..dc1f37b666b 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_macros.h"
 #include "archetypes.hpp"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<float, short*> P;
@@ -51,4 +51,6 @@ int main()
         static_assert(!std::is_default_constructible<P2>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp
index df9cbc75756..268ec4294c7 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp
@@ -26,10 +26,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   static_assert((std::is_trivially_destructible<
       std::pair<int, float> >::value), "");
   static_assert((!std::is_trivially_destructible<
       std::pair<int, std::string> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp
index 4b7529388cd..ca5a728844e 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp
@@ -39,7 +39,7 @@
 // (6)  explicit pair(pair<U1, U2> const&) -> pair<U1, U2>
 // (7)  pair(pair<U1, U2> &&) -> pair<U1, U2>
 // (8)  explicit pair(pair<U1, U2> &&) -> pair<U1, U2>
-int main()
+int main(int, char**)
 {
   using E = ExplicitTestTypes::TestType;
   static_assert(!std::is_convertible<E const&, E>::value, "");
@@ -76,4 +76,6 @@ int main()
     std::pair p1(std::move(p));
     ASSERT_SAME_TYPE(decltype(p1), std::pair<std::string, E>);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp
index 92a0aa42b14..53d81ac7aac 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp
@@ -25,7 +25,7 @@ struct Dummy {
   Dummy(Dummy &&) = default;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -40,4 +40,6 @@ int main()
         static_assert(!std::is_copy_constructible<P>::value, "");
         static_assert(std::is_move_constructible<P>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp
index 325499eafaf..88d0f964939 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp
@@ -27,7 +27,7 @@ struct ImplicitT {
   int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         using P = std::pair<int, int>;
@@ -53,4 +53,6 @@ int main()
         constexpr P U_V = {42, 101}; // expected-error {{must be initialized by a constant expression}}
         constexpr P pair_U_V = other; // expected-error {{must be initialized by a constant expression}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp
index 3c93eeb3dca..26b02f383ad 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp
@@ -21,7 +21,7 @@
 #include <utility>
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, int*> P1;
@@ -32,4 +32,6 @@ int main()
         assert(p3.first == P1(3, nullptr));
         assert(p3.second == P2(nullptr, 4));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp
index b38ca2a3b72..0e3d9a1cb70 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp
@@ -63,7 +63,7 @@ struct ImplicitT {
   int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<Derived>, int> P1;
@@ -173,4 +173,6 @@ int main()
         static_assert(p2.second.value == 43, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp
index 48ea5fac6e9..db174e829bd 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp
@@ -120,7 +120,9 @@ void test_assignment_operator_exists() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_constructors_exist();
   test_assignment_operator_exists();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp
index 58a5c29326a..faaae1bc255 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp
@@ -24,7 +24,7 @@ struct S {
     bool operator==(int x) const { return i == x; }
     };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -46,4 +46,6 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp
index e4b444a349f..6841f286553 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp
@@ -26,7 +26,7 @@ struct Dummy {
   Dummy(Dummy &&) = default;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<int, short> P;
     {
@@ -52,4 +52,6 @@ int main()
 #endif
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp
index abda1d8c3b9..25108de5bbe 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp
@@ -17,9 +17,11 @@
 #include <utility>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<float, short*> P;
     static_assert((std::is_same<P::first_type, float>::value), "");
     static_assert((std::is_same<P::second_type, short*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp
index 3b994dfd4df..12d6ab01917 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -94,4 +94,6 @@ int main()
         static_assert( (p1 >= p2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
index 3586243f8ba..dff26e57f0b 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -49,4 +49,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp
index 62fa9424794..87432767217 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -28,4 +28,6 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/synopsis.pass.cpp b/libcxx/test/std/utilities/utility/synopsis.pass.cpp
index 90c5e32186d..5a703e1b2e5 100644
--- a/libcxx/test/std/utilities/utility/synopsis.pass.cpp
+++ b/libcxx/test/std/utilities/utility/synopsis.pass.cpp
@@ -13,9 +13,11 @@
 
 #include <utility>
 
-int main()
+int main(int, char**)
 {
     std::initializer_list<int> x;
     (void)x;
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp b/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp
index 53fa3cf6655..155b2c0eb21 100644
--- a/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp
@@ -42,7 +42,7 @@ constexpr bool check_tag(Up) {
         && std::is_same<Tp, Up>::value;
 }
 
-int main() {
+int main(int, char**) {
     // test in_place_t
     {
         using T = std::in_place_t;
@@ -70,4 +70,6 @@ int main() {
         static_assert(check_tag<T2>(std::in_place_index<1>));
         static_assert(check_tag<T3>(std::in_place_index<static_cast<size_t>(-1)>));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp b/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp
index 9dda5a42c1f..f52af4cb896 100644
--- a/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp
@@ -62,7 +62,7 @@ constexpr bool can_swap() {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -99,4 +99,6 @@ int main()
         static_assert(noexcept(std::swap(nm, nm)), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp b/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp
index 202e8d33f23..015e85a0135 100644
--- a/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp
@@ -54,7 +54,7 @@ constexpr bool can_swap() {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
         int i[3] = {1, 2, 3};
@@ -97,4 +97,6 @@ int main()
         static_assert(noexcept(std::swap(ma, ma)), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp b/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp
index 1585e1745ba..cb66771fc43 100644
--- a/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp
@@ -35,11 +35,13 @@ public:
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
   static_assert(std::is_base_of<std::exception, std::bad_variant_access>::value,
                 "");
   static_assert(noexcept(std::bad_variant_access{}), "must be noexcept");
   static_assert(noexcept(std::bad_variant_access{}.what()), "must be noexcept");
   std::bad_variant_access ex;
   assert(ex.what());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp
index 0c118a0f5f5..8002e55766c 100644
--- a/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp
@@ -7,4 +7,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp
index 505a8cb8e65..5210c5f9d84 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp
@@ -125,7 +125,9 @@ void test_get_if() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_get_if();
   test_get_if();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp
index 3cb0fc7054e..e7c9671f95c 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp
@@ -123,7 +123,9 @@ void test_get_if() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_get_if();
   test_get_if();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp
index a5a629adb96..5519c4263b7 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp
@@ -285,10 +285,12 @@ void test_throws_for_all_value_categories() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_lvalue_get();
   test_lvalue_get();
   test_rvalue_get();
   test_const_rvalue_get();
   test_throws_for_all_value_categories();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp
index b4cae102705..76bbbb026e4 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp
@@ -285,10 +285,12 @@ void test_throws_for_all_value_categories() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_lvalue_get();
   test_lvalue_get();
   test_rvalue_get();
   test_const_rvalue_get();
   test_throws_for_all_value_categories();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp
index 3e9cfbe9c47..b37462069df 100644
--- a/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include <variant>
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int>;
     constexpr V v;
@@ -34,4 +34,6 @@ int main() {
     const V v;
     ASSERT_NOEXCEPT(std::holds_alternative<int>(v));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp
index 404f3e7e5b4..7e9ffbfa06e 100644
--- a/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp b/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
index 5acf168ad8c..edda8d21a24 100644
--- a/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
@@ -150,9 +150,11 @@ void test_hash_variant_enabled() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_hash_variant();
   test_hash_variant_duplicate_elements();
   test_hash_monostate();
   test_hash_variant_enabled();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp
index f7db0d86bee..48d5e14e260 100644
--- a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp
@@ -25,7 +25,9 @@
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
     using V = std::variant<int, void *, const void *, long double>;
     std::variant_alternative<4, V>::type foo;  // expected-error@variant:* {{Index out of bounds in std::variant_alternative<>}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp
index 841f65cb127..7db07b6b0d4 100644
--- a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp
@@ -55,7 +55,7 @@ template <class V, size_t I, class E> void test() {
                 "");
 }
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, void *, const void *, long double>;
     test<V, 0, int>();
@@ -73,4 +73,6 @@ int main() {
     test<V, 4, long double>();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp b/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp
index f7e200b241a..fb027fb6380 100644
--- a/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp
@@ -36,8 +36,10 @@ template <class V, size_t E> void test() {
                 "");
 };
 
-int main() {
+int main(int, char**) {
   test<std::variant<>, 0>();
   test<std::variant<void *>, 1>();
   test<std::variant<long, long, void *, double>, 4>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp b/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp
index 2df4b2bacf5..255f6d0342e 100644
--- a/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp
@@ -23,7 +23,7 @@
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
   using M = std::monostate;
   constexpr M m1{};
   constexpr M m2{};
@@ -51,4 +51,6 @@ int main() {
     static_assert((m1 != m2) == false, "");
     ASSERT_NOEXCEPT(m1 != m2);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp b/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp
index 1d7bcaca4db..1ba75a77907 100644
--- a/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp
@@ -16,7 +16,7 @@
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
   using M = std::monostate;
   static_assert(std::is_trivially_default_constructible<M>::value, "");
   static_assert(std::is_trivially_copy_constructible<M>::value, "");
@@ -24,4 +24,6 @@ int main() {
   static_assert(std::is_trivially_destructible<M>::value, "");
   constexpr M m{};
   ((void)m);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp b/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
index 1950b5a383d..ed32215ffdc 100644
--- a/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
@@ -269,7 +269,9 @@ void test_relational() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_equality();
   test_relational();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp b/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
index d03a6b5d5b1..e46893465bc 100644
--- a/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
@@ -72,7 +72,7 @@ inline constexpr MyBoolExplicit operator>=(const ComparesToMyBoolExplicit& LHS,
 }
 
 
-int main() {
+int main(int, char**) {
   using V = std::variant<int, ComparesToMyBoolExplicit>;
   V v1(42);
   V v2(101);
@@ -84,4 +84,6 @@ int main() {
   (void)(v1 <= v2); // expected-note {{here}}
   (void)(v1 > v2); // expected-note {{here}}
   (void)(v1 >= v2); // expected-note {{here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp b/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp
index aadda7eacbb..310b6980c1a 100644
--- a/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp
@@ -15,6 +15,8 @@
 
 #include <variant>
 
-int main() {
+int main(int, char**) {
   static_assert(std::variant_npos == static_cast<std::size_t>(-1), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp
index 67deb3f2c62..6a4bb048627 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp
@@ -254,10 +254,12 @@ void test_T_assignment_performs_assignment() {
 #endif // TEST_HAS_NO_EXCEPTIONS
 }
 
-int main() {
+int main(int, char**) {
   test_T_assignment_basic();
   test_T_assignment_performs_construction();
   test_T_assignment_performs_assignment();
   test_T_assignment_noexcept();
   test_T_assignment_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp
index 6a59989ddad..c36375cf299 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp
@@ -590,7 +590,7 @@ void test_constexpr_copy_assignment() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_copy_assignment_empty_empty();
   test_copy_assignment_non_empty_empty();
   test_copy_assignment_empty_non_empty();
@@ -599,4 +599,6 @@ int main() {
   test_copy_assignment_sfinae();
   test_copy_assignment_not_noexcept();
   test_constexpr_copy_assignment();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp
index 833883d294f..c213af4b2e7 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp
@@ -506,7 +506,7 @@ void test_constexpr_move_assignment() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_move_assignment_empty_empty();
   test_move_assignment_non_empty_empty();
   test_move_assignment_empty_non_empty();
@@ -515,4 +515,6 @@ int main() {
   test_move_assignment_sfinae();
   test_move_assignment_noexcept();
   test_constexpr_move_assignment();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp
index 7357b9b56c0..4ebfe052de1 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp
@@ -126,8 +126,10 @@ void test_T_ctor_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_T_ctor_basic();
   test_T_ctor_noexcept();
   test_T_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp
index b6471052f64..00c94ee33c3 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp
@@ -260,7 +260,7 @@ void test_constexpr_copy_ctor() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_copy_ctor_basic();
   test_copy_ctor_valueless_by_exception();
   test_copy_ctor_sfinae();
@@ -274,4 +274,6 @@ int main() {
   (void) v2;
 }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp
index ec6eb289ba6..1766ee1dbc0 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp
@@ -122,9 +122,11 @@ void test_default_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_default_ctor_basic();
   test_default_ctor_sfinae();
   test_default_ctor_noexcept();
   test_default_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp
index a268adcea50..cb7d68a659f 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp
@@ -104,7 +104,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
index 9c7e3faf862..4b78bf5690a 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
@@ -110,7 +110,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp
index 05b2a29ce8f..ab8fe068831 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp
@@ -114,7 +114,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp
index c3f3e58d346..4061cfb2528 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp
@@ -111,7 +111,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp
index ecb4a720755..f146e16d3c0 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp
@@ -331,10 +331,12 @@ void test_constexpr_move_ctor() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_move_ctor_basic();
   test_move_ctor_valueless_by_exception();
   test_move_noexcept();
   test_move_ctor_sfinae();
   test_constexpr_move_ctor();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
index 8ced5321b69..b26ab0c29bf 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
@@ -44,7 +44,7 @@ struct TDtor {
 static_assert(!std::is_trivially_copy_constructible<TDtor>::value, "");
 static_assert(std::is_trivially_destructible<TDtor>::value, "");
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, long, TDtor>;
     static_assert(std::is_trivially_destructible<V>::value, "");
@@ -71,4 +71,6 @@ int main() {
     assert(NonTDtor::count == 0);
     assert(NonTDtor1::count == 1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
index ea84ac94072..b688c8e7a54 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
@@ -159,7 +159,9 @@ void test_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
index 13e3c927c28..9d96a1dc272 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
@@ -92,7 +92,9 @@ void test_basic() {
   assert(&ref3 == &std::get<1>(v));
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
index 7c9034f10a7..0719f5e7bdc 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
@@ -159,7 +159,9 @@ void test_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
index 85cd25d04de..49839eda4f3 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
@@ -92,7 +92,9 @@ void test_basic() {
   assert(&ref3 == &std::get<InitList>(v));
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
index 0afa10138e3..6d463ad2788 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
@@ -25,7 +25,7 @@
 #include "variant_test_helpers.hpp"
 
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, long>;
     constexpr V v;
@@ -57,4 +57,6 @@ int main() {
     assert(v.index() == std::variant_npos);
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
index 147f380a19f..2cb730cb0ff 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
@@ -25,7 +25,7 @@
 #include "variant_test_helpers.hpp"
 
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, long>;
     constexpr V v;
@@ -50,4 +50,6 @@ int main() {
     assert(v.valueless_by_exception());
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
index e05cd13e69f..4e273f52e5e 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
@@ -589,10 +589,12 @@ void test_swap_noexcept() {
 template class std::variant<int, NotSwappable>;
 #endif
 
-int main() {
+int main(int, char**) {
   test_swap_valueless_by_exception();
   test_swap_same_alternative();
   test_swap_different_alternatives();
   test_swap_sfinae();
   test_swap_noexcept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp
index a9caeb8b2db..ce79e9c4254 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp
@@ -23,10 +23,12 @@
 #include "variant_test_helpers.hpp"
 #include "test_convertible.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 3 {{static_assert failed}}
     std::variant<int, int[]> v; // expected-note {{requested here}}
     std::variant<int, int[42]> v2; // expected-note {{requested here}}
     std::variant<int, int[][42]> v3; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp
index 85a10eff9af..3b93cb0ab70 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp
@@ -18,8 +18,10 @@
 #include "test_macros.h"
 #include "variant_test_helpers.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 1 {{static_assert failed}}
     std::variant<> v; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp
index e659f47600a..7c2c4669083 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp
@@ -18,10 +18,12 @@
 #include "test_macros.h"
 #include "variant_test_helpers.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 3 {{static_assert failed}}
     std::variant<int, int&> v; // expected-note {{requested here}}
     std::variant<int, const int &> v2; // expected-note {{requested here}}
     std::variant<int, int&&> v3; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp
index ce0675d73c6..27e9c399f8d 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp
@@ -23,10 +23,12 @@
 #include "variant_test_helpers.hpp"
 #include "test_convertible.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 3 {{static_assert failed}}
     std::variant<int, void> v; // expected-note {{requested here}}
     std::variant<int, const void> v2; // expected-note {{requested here}}
     std::variant<const volatile void, int> v3; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp b/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp
index 198f310e9af..15a1de9842c 100644
--- a/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp
@@ -310,10 +310,12 @@ void test_caller_accepts_nonconst() {
   std::visit(Visitor{}, v);
 }
 
-int main() {
+int main(int, char**) {
   test_call_operator_forwarding();
   test_argument_forwarding();
   test_constexpr();
   test_exceptions();
   test_caller_accepts_nonconst();
+
+  return 0;
 }