text: //===----------------------------------------------------------------------===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  //
  // UNSUPPORTED: libcpp-has-no-threads
  //
  // ALLOW_RETRIES: 2
  
  // <mutex>
  
  // class timed_mutex;
  
  // bool try_lock();
  
  #include <mutex>
  #include <thread>
  #include <cstdlib>
  #include <cassert>
  
  #include "test_macros.h"
  
  std::timed_mutex m;
  
  typedef std::chrono::system_clock Clock;
  typedef Clock::time_point time_point;
  typedef Clock::duration duration;
  typedef std::chrono::milliseconds ms;
  typedef std::chrono::nanoseconds ns;
  
  void f()
  {
      time_point t0 = Clock::now();
      assert(!m.try_lock());
      assert(!m.try_lock());
      assert(!m.try_lock());
      while(!m.try_lock())
          ;
      time_point t1 = Clock::now();
      m.unlock();
      ns d = t1 - t0 - ms(250);
      assert(d < ms(200));  // within 200ms
  }
  
  int main(int, char**)
  {
      m.lock();
      std::thread t(f);
      std::this_thread::sleep_for(ms(250));
      m.unlock();
      t.join();
  
    return 0;
  }
  