thread/test/sync/mutual_exclusion/shared_mutex/try_lock_pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// Copyright (C) 2012 Vicente J. Botet Escriba
//
//  Distributed under the Boost Software License, Version 1.0. (See accompanying
//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

// <boost/thread/shared_mutex.hpp>

// class shared_mutex;

// bool try_lock();

#include <boost/thread/shared_mutex.hpp>
#include <boost/thread/thread.hpp>
#include <boost/detail/lightweight_test.hpp>

boost::shared_mutex m;

typedef boost::chrono::system_clock Clock;
typedef Clock::time_point time_point;
typedef Clock::duration duration;
typedef boost::chrono::milliseconds ms;
typedef boost::chrono::nanoseconds ns;

void f()
{
  time_point t0 = Clock::now();
  BOOST_TEST(!m.try_lock());
  BOOST_TEST(!m.try_lock());
  BOOST_TEST(!m.try_lock());
  while (!m.try_lock())
    ;
  time_point t1 = Clock::now();
  m.unlock();
  ns d = t1 - t0 - ms(250);
  // This test is spurious as it depends on the time the thread system switches the threads
  BOOST_TEST(d < ns(50000000)+ms(1000)); // within 50ms
}

int main()
{
  m.lock();
  boost::thread t(f);
  boost::this_thread::sleep_for(ms(250));
  m.unlock();
  t.join();

  return boost::report_errors();
}