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

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <mutex>

// template <class Mutex> class unique_lock;

// explicit operator bool() const noexcept;

#include <cassert>
#include <mutex>
#include <type_traits>

#include "checking_mutex.h"
#include "test_macros.h"

#if TEST_STD_VER >= 11
static_assert(noexcept(static_cast<bool>(std::declval<std::unique_lock<checking_mutex>&>())), "");
#endif

int main(int, char**) {
  static_assert(std::is_constructible<bool, std::unique_lock<checking_mutex> >::value, "");
  static_assert(!std::is_convertible<std::unique_lock<checking_mutex>, bool>::value, "");

  checking_mutex mux;
  const std::unique_lock<checking_mutex> lk0; // Make sure `operator bool()` is `const`
  assert(!static_cast<bool>(lk0));
  std::unique_lock<checking_mutex> lk1(mux);
  assert(static_cast<bool>(lk1));
  lk1.unlock();
  assert(!static_cast<bool>(lk1));

  ASSERT_NOEXCEPT(static_cast<bool>(lk0));

  return 0;
}