1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // UNSUPPORTED: no-threads
10 
11 // <mutex>
12 
13 // template <class Mutex> class lock_guard;
14 
15 // explicit lock_guard(mutex_type& m);
16 
17 // template<class _Mutex> lock_guard(lock_guard<_Mutex>)
18 //     -> lock_guard<_Mutex>;  // C++17
19 
20 #include <mutex>
21 #include <cstdlib>
22 #include <cassert>
23 
24 #include "make_test_thread.h"
25 #include "test_macros.h"
26 
27 std::mutex m;
28 
do_try_lock()29 void do_try_lock() {
30   assert(m.try_lock() == false);
31 }
32 
main(int,char **)33 int main(int, char**) {
34   {
35     std::lock_guard<std::mutex> lg(m);
36     std::thread t = support::make_test_thread(do_try_lock);
37     t.join();
38   }
39 
40   m.lock();
41   m.unlock();
42 
43 #if TEST_STD_VER >= 17
44   std::lock_guard lg(m);
45   static_assert((std::is_same<decltype(lg), std::lock_guard<decltype(m)>>::value), "" );
46 #endif
47 
48   return 0;
49 }
50