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///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2005-2012, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Industrial Light & Magic nor the names of
// its contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
///////////////////////////////////////////////////////////////////////////
#ifndef INCLUDED_ILM_THREAD_SEMAPHORE_H
#define INCLUDED_ILM_THREAD_SEMAPHORE_H
//-----------------------------------------------------------------------------
//
// class Semaphore -- a wrapper class for
// system-dependent counting semaphores
//
//-----------------------------------------------------------------------------
#include "IlmBaseConfig.h"
#include "IlmThreadExport.h"
#include "IlmThreadNamespace.h"
#if defined _WIN32 || defined _WIN64
# ifdef NOMINMAX
# undef NOMINMAX
# endif
# define NOMINMAX
# include <windows.h>
#elif HAVE_POSIX_SEMAPHORES
# include <semaphore.h>
#else
# ifdef ILMBASE_FORCE_CXX03
# if HAVE_PTHREAD
# include <pthread.h>
# endif
# else
# include <mutex>
# include <condition_variable>
# endif
#endif
ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER
class ILMTHREAD_EXPORT Semaphore
{
public:
Semaphore (unsigned int value = 0);
virtual ~Semaphore();
void wait();
bool tryWait();
void post();
int value() const;
private:
#if defined _WIN32 || defined _WIN64
mutable HANDLE _semaphore;
#elif defined(HAVE_POSIX_SEMAPHORES)
mutable sem_t _semaphore;
#else
//
// If the platform has Posix threads but no semapohores,
// then we implement them ourselves using condition variables
//
struct sema_t
{
unsigned int count;
unsigned long numWaiting;
# if ILMBASE_FORCE_CXX03
# if HAVE_PTHREAD
pthread_mutex_t mutex;
pthread_cond_t nonZero;
# else
# error unhandled legacy setup
# endif
# else
std::mutex mutex;
std::condition_variable nonZero;
# endif
};
mutable sema_t _semaphore;
#endif
void operator = (const Semaphore& s); // not implemented
Semaphore (const Semaphore& s); // not implemented
};
ILMTHREAD_INTERNAL_NAMESPACE_HEADER_EXIT
#endif // INCLUDED_ILM_THREAD_SEMAPHORE_H
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