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//
// Semaphore_POSIX.h
//
// Library: Foundation
// Package: Threading
// Module: Semaphore
//
// Definition of the SemaphoreImpl class for POSIX Threads.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_Semaphore_POSIX_INCLUDED
#define Foundation_Semaphore_POSIX_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Exception.h"
#include <pthread.h>
#include <errno.h>
#include <atomic>
namespace Poco {
class Foundation_API SemaphoreImpl
{
protected:
SemaphoreImpl(int n, int max);
~SemaphoreImpl();
void setImpl();
void waitImpl();
bool waitImpl(long milliseconds);
private:
std::atomic<int> _n;
int _max;
pthread_mutex_t _mutex;
pthread_cond_t _cond;
};
//
// inlines
//
inline void SemaphoreImpl::setImpl()
{
if (pthread_mutex_lock(&_mutex))
throw SystemException("cannot signal semaphore (lock)");
if (_n < _max)
{
++_n;
}
else
{
pthread_mutex_unlock(&_mutex);
throw SystemException("cannot signal semaphore: count would exceed maximum");
}
if (pthread_cond_signal(&_cond))
{
pthread_mutex_unlock(&_mutex);
throw SystemException("cannot signal semaphore");
}
pthread_mutex_unlock(&_mutex);
}
} // namespace Poco
#endif // Foundation_Semaphore_POSIX_INCLUDED
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