Only initialize the streams cout/wcout/cerr/wcerr etc once, rather than any time Init::Init is called. Fixes PR#43300

llvm-svn: 371864

1 files changed, 32 insertions, 0 deletions

diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/ios_Init.multiple.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/ios_Init.multiple.pass.cpp
new file mode 100644
index 00000000000..37b4de9def5
--- /dev/null
+++ b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.types/ios_Init/ios_Init.multiple.pass.cpp
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <iostream>
+#include <cassert>
+
+#include "test_macros.h"
+
+// Test to make sure that the streams only get initialized once
+// Taken from https://bugs.llvm.org/show_bug.cgi?id=43300
+
+int main(int, char**)
+{
+
+    std::cout << "Hello!";
+    std::ios_base::fmtflags stock_flags = std::cout.flags();
+
+    std::cout << std::boolalpha << true;
+    std::ios_base::fmtflags ba_flags = std::cout.flags();
+    assert(stock_flags != ba_flags);
+
+    std::ios_base::Init init_streams;
+    std::ios_base::fmtflags after_init = std::cout.flags();
+    assert(after_init == ba_flags);
+
+    return 0;
+}