Implement P0426: Constexpr for std::char_traits

llvm-svn: 291741

1 files changed, 18 insertions, 0 deletions

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 ead3f32fcc7..80aca0ea7f9 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
@@ -12,10 +12,24 @@
 // template<> struct char_traits<wchar_t>
 
 // static const char_type* find(const char_type* s, size_t n, const char_type& a);
+// constexpr in C++17
 
 #include <string>
 #include <cassert>
 
+#include "test_macros.h"
+
+#if TEST_STD_VER > 14
+constexpr bool test_constexpr()
+{
+    constexpr const wchar_t *p = L"123";
+    return std::char_traits<wchar_t>::find(p, 3, L'1') == p
+        && std::char_traits<wchar_t>::find(p, 3, L'2') == p + 1
+        && std::char_traits<wchar_t>::find(p, 3, L'3') == p + 2
+        && std::char_traits<wchar_t>::find(p, 3, L'4') == nullptr;
+}
+#endif
+
 int main()
 {
     wchar_t s1[] = {1, 2, 3};
@@ -25,4 +39,8 @@ int main()
     assert(std::char_traits<wchar_t>::find(s1, 3, wchar_t(4)) == 0);
     assert(std::char_traits<wchar_t>::find(s1, 3, wchar_t(0)) == 0);
     assert(std::char_traits<wchar_t>::find(NULL, 0, wchar_t(0)) == 0);
+
+#if TEST_STD_VER > 14
+    static_assert(test_constexpr(), "" );
+#endif
 }