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//

// NamedMutex.h

//

// $Id: //poco/1.3/Foundation/include/Poco/NamedMutex.h#1 $

//

// Library: Foundation

// Package: Processes

// Module:  NamedMutex

//

// Definition of the NamedMutex class.

//

// 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.

//

#ifndef Foundation_NamedMutex_INCLUDED

#define Foundation_NamedMutex_INCLUDED

#include "Poco/Foundation.h"

#include "Poco/ScopedLock.h"

#if defined(POCO_OS_FAMILY_WINDOWS) && defined(POCO_WIN32_UTF8)

#include "Poco/NamedMutex_WIN32U.h"

#elif defined(POCO_OS_FAMILY_WINDOWS)

#include "Poco/NamedMutex_WIN32.h"

#elif defined(POCO_OS_FAMILY_UNIX)

#include "Poco/NamedMutex_UNIX.h"

#else

#include "Poco/NamedMutex_VMS.h"

#endif

namespace Poco {

class Foundation_API NamedMutex: private NamedMutexImpl

        /// A NamedMutex (mutual exclusion) is a global synchronization 

        /// mechanism used to control access to a shared resource

        /// in a concurrent (multi process) scenario.

        /// Using the ScopedLock class is the preferred way to automatically

        /// lock and unlock a mutex.

        ///

        /// Unlike a Mutex or a FastMutex, which itself is the unit of synchronization,

        /// a NamedMutex refers to a named operating system resource being the

        /// unit of synchronization.

        /// In other words, there can be multiple instances of NamedMutex referring

        /// to the same actual synchronization object.

        ///

        ///

        /// There should not be more than one instance of NamedMutex for

        /// a given name in a process. Otherwise, the instances may

        /// interfere with each other.

{

public:

        typedef Poco::ScopedLock<NamedMutex> ScopedLock;

        NamedMutex(const std::string& name);

                /// creates the Mutex.

        ~NamedMutex();

                /// destroys the Mutex.

        void lock();

                /// Locks the mutex. Blocks if the mutex

                /// is held by another process or thread.

        bool tryLock();

                /// Tries to lock the mutex. Returns false immediately

                /// if the mutex is already held by another process or thread.

                /// Returns true if the mutex was successfully locked.

        void unlock();

                /// Unlocks the mutex so that it can be acquired by

                /// other threads.

private:

        NamedMutex();

        NamedMutex(const NamedMutex&);

        NamedMutex& operator = (const NamedMutex&);

};

//

// inlines

//

inline void NamedMutex::lock()

{

        lockImpl();

}

inline bool NamedMutex::tryLock()

{

        return tryLockImpl();

}

inline void NamedMutex::unlock()

{

        unlockImpl();

}

} // namespace Poco

#endif // Foundation_NamedMutex_INCLUDED