topical media & game development
lib-of-vs-libs-Poco-include-Poco-Mutex.h / h
//
// Mutex.h
//
//
//
// Library: Foundation
// Package: Threading
// Module: Mutex
//
// Definition of the Mutex and FastMutex classes.
//
// Copyright (c) 2004-2008, 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_Mutex_INCLUDED
define Foundation_Mutex_INCLUDED
include "Poco/Foundation.h"
include "Poco/Exception.h"
include "Poco/ScopedLock.h"
if defined(POCO_OS_FAMILY_WINDOWS)
include "Poco/Mutex_WIN32.h"
else
include "Poco/Mutex_POSIX.h"
endif
namespace Poco {
class Foundation_API Mutex: private MutexImpl
A Mutex (mutual exclusion) is a synchronization
mechanism used to control access to a shared resource
in a concurrent (multithreaded) scenario.
Mutexes are recursive, that is, the same mutex can be
locked multiple times by the same thread (but, of course,
not by other threads).
Using the ScopedLock class is the preferred way to automatically
lock and unlock a mutex.
{
public:
typedef Poco::ScopedLock<Mutex> ScopedLock;
Mutex();
creates the Mutex.
~Mutex();
destroys the Mutex.
void lock();
Locks the mutex. Blocks if the mutex
is held by another thread.
void lock(long milliseconds);
Locks the mutex. Blocks up to the given number of milliseconds
if the mutex is held by another thread. Throws a TimeoutException
if the mutex can not be locked within the given timeout.
Performance Note: On most platforms (including Windows), this member function is
implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
On POSIX platforms that support pthread_mutex_timedlock(), this is used.
bool tryLock();
Tries to lock the mutex. Returns false immediately
if the mutex is already held by another thread.
Returns true if the mutex was successfully locked.
bool tryLock(long milliseconds);
Locks the mutex. Blocks up to the given number of milliseconds
if the mutex is held by another thread.
Returns true if the mutex was successfully locked.
Performance Note: On most platforms (including Windows), this member function is
implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
On POSIX platforms that support pthread_mutex_timedlock(), this is used.
void unlock();
Unlocks the mutex so that it can be acquired by
other threads.
private:
Mutex(const Mutex&);
Mutex& operator = (const Mutex&);
};
class Foundation_API FastMutex: private FastMutexImpl
A FastMutex (mutual exclusion) is similar to a Mutex.
Unlike a Mutex, however, a FastMutex is not recursive,
which means that a deadlock will occur if the same
thread tries to lock a mutex it has already locked again.
Locking a FastMutex is faster than locking a recursive Mutex.
Using the ScopedLock class is the preferred way to automatically
lock and unlock a mutex.
{
public:
typedef Poco::ScopedLock<FastMutex> ScopedLock;
FastMutex();
creates the Mutex.
~FastMutex();
destroys the Mutex.
void lock();
Locks the mutex. Blocks if the mutex
is held by another thread.
void lock(long milliseconds);
Locks the mutex. Blocks up to the given number of milliseconds
if the mutex is held by another thread. Throws a TimeoutException
if the mutex can not be locked within the given timeout.
Performance Note: On most platforms (including Windows), this member function is
implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
On POSIX platforms that support pthread_mutex_timedlock(), this is used.
bool tryLock();
Tries to lock the mutex. Returns false immediately
if the mutex is already held by another thread.
Returns true if the mutex was successfully locked.
bool tryLock(long milliseconds);
Locks the mutex. Blocks up to the given number of milliseconds
if the mutex is held by another thread.
Returns true if the mutex was successfully locked.
Performance Note: On most platforms (including Windows), this member function is
implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
On POSIX platforms that support pthread_mutex_timedlock(), this is used.
void unlock();
Unlocks the mutex so that it can be acquired by
other threads.
private:
FastMutex(const FastMutex&);
FastMutex& operator = (const FastMutex&);
};
//
// inlines
//
inline void Mutex::lock()
{
lockImpl();
}
inline void Mutex::lock(long milliseconds)
{
if (!tryLockImpl(milliseconds))
throw TimeoutException();
}
inline bool Mutex::tryLock()
{
return tryLockImpl();
}
inline bool Mutex::tryLock(long milliseconds)
{
return tryLockImpl(milliseconds);
}
inline void Mutex::unlock()
{
unlockImpl();
}
inline void FastMutex::lock()
{
lockImpl();
}
inline void FastMutex::lock(long milliseconds)
{
if (!tryLockImpl(milliseconds))
throw TimeoutException();
}
inline bool FastMutex::tryLock()
{
return tryLockImpl();
}
inline bool FastMutex::tryLock(long milliseconds)
{
return tryLockImpl(milliseconds);
}
inline void FastMutex::unlock()
{
unlockImpl();
}
} // namespace Poco
endif // Foundation_Mutex_INCLUDED
(C) Æliens
04/09/2009
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