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 unique_lock;
14 
15 // explicit operator bool() const noexcept;
16 
17 #include <mutex>
18 #include <cassert>
19 #include <type_traits>
20 
21 #include "test_macros.h"
22 
23 std::mutex m;
24 
main(int,char **)25 int main(int, char**)
26 {
27     static_assert(std::is_constructible<bool, std::unique_lock<std::mutex> >::value, "");
28     static_assert(!std::is_convertible<std::unique_lock<std::mutex>, bool>::value, "");
29 
30     std::unique_lock<std::mutex> lk0;
31     assert(static_cast<bool>(lk0) == false);
32     std::unique_lock<std::mutex> lk1(m);
33     assert(static_cast<bool>(lk1) == true);
34     lk1.unlock();
35     assert(static_cast<bool>(lk1) == false);
36     ASSERT_NOEXCEPT(static_cast<bool>(lk0));
37 
38   return 0;
39 }
40