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 // <mutex>
  10
  11 // template <class Mutex> class unique_lock;
  12
  13 // explicit operator bool() const noexcept;
  14
  15 #include <cassert>
  16 #include <mutex>
  17 #include <type_traits>
  18
  19 #include "checking_mutex.h"
  20 #include "test_macros.h"
  21
  22 #if TEST_STD_VER >= 11
  23 static_assert(noexcept(static_cast<bool>(std::declval<std::unique_lock<checking_mutex>&>())), "");
  24 #endif
  25
  26 int main(int, char**) {
  27   static_assert(std::is_constructible<bool, std::unique_lock<checking_mutex> >::value, "");
  28   static_assert(!std::is_convertible<std::unique_lock<checking_mutex>, bool>::value, "");
  29
  30   checking_mutex mux;
  31   const std::unique_lock<checking_mutex> lk0; // Make sure `operator bool()` is `const`
  32   assert(!static_cast<bool>(lk0));
  33   std::unique_lock<checking_mutex> lk1(mux);
  34   assert(static_cast<bool>(lk1));
  35   lk1.unlock();
  36   assert(!static_cast<bool>(lk1));
  37
  38   ASSERT_NOEXCEPT(static_cast<bool>(lk0));
  39
  40   return 0;
  41 }