///////////////////////////////////////////////////////////////////////////

//

// 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,

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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

///////////////////////////////////////////////////////////////////////////

//-----------------------------------------------------------------------------

//

//	class Semaphore -- implementation for platforms

//	that support Posix threads and Posix semaphores

//

//-----------------------------------------------------------------------------

#include "IlmBaseConfig.h"

#if HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES

#include "IlmThreadSemaphore.h"

#include "Iex.h"

#include <assert.h>

#include <errno.h>

ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_ENTER

Semaphore::Semaphore (unsigned int value)

{

    if (::sem_init (&_semaphore, 0, value))

	IEX_NAMESPACE::throwErrnoExc ("Cannot initialize semaphore (%T).");

}

Semaphore::~Semaphore ()

{

    int error = ::sem_destroy (&_semaphore);

    assert (error == 0);

}

void

Semaphore::wait ()

{

    while( ::sem_wait( &_semaphore ) == -1 && errno == EINTR )

    {

    }

}

bool

Semaphore::tryWait ()

{

    return sem_trywait (&_semaphore) == 0;

}

void

Semaphore::post ()

{

    if (::sem_post (&_semaphore))

        IEX_NAMESPACE::throwErrnoExc ("Post operation on semaphore failed (%T).");

}

int

Semaphore::value () const

{

    int value;

    if (::sem_getvalue (&_semaphore, &value))

        IEX_NAMESPACE::throwErrnoExc ("Cannot read semaphore value (%T).");

    return value;

}

ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_EXIT

#endif