libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp

   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
  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 }