Wrestling with the slowly dawning realization that <atomic> isn't implementable on any compiler at my disposal...

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@115054 91177308-0d34-0410-b5e6-96231b3b80d8

test/atomics/atomics.flag/test_and_set.pass.cpp

@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <atomic>
+
+// struct atomic_flag
+
+// bool test_and_set(memory_order = memory_order_seq_cst);
+// bool test_and_set(memory_order = memory_order_seq_cst) volatile;
+
+#include <atomic>
+#include <cassert>
+
+int main()
+{
+    std::atomic_flag f = ATOMIC_FLAG_INIT;
+    assert(f.test_and_set() == 0);
+    assert(f.test_and_set() == 1);
+}