Mutex_WIN32.cpp

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//
// Mutex_WIN32.cpp
//
// $Id: //poco/1.3/Foundation/src/Mutex_WIN32.cpp#3 $
//
// Library: Foundation
// Package: Threading
// Module:  Mutex
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#include "Poco/Mutex_WIN32.h"
#include "Poco/Timestamp.h"


namespace Poco {


MutexImpl::MutexImpl()
{
        // the fct has a boolean return value under WInnNt/2000/XP but not on Win98
        // the return only checks if the input address of &_cs was valid, so it is safe to omit it
        InitializeCriticalSectionAndSpinCount(&_cs, 4000);
}


MutexImpl::~MutexImpl()
{
        DeleteCriticalSection(&_cs);
}


bool MutexImpl::tryLockImpl(long milliseconds)
{
        const int sleepMillis = 5;
        Timestamp now;
        Timestamp::TimeDiff diff(Timestamp::TimeDiff(milliseconds)*1000);
        do
        {
                try
                {
                        if (TryEnterCriticalSection(&_cs) == TRUE)
                                return true;
                }
                catch (...)
                {
                        throw SystemException("cannot lock mutex");
                }
                Sleep(sleepMillis);
        }
        while (!now.isElapsed(diff));
        return false;
}


} // namespace Poco