semaphore-private.h

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/*
  Copyright 1999-2010 ImageMagick Studio LLC, a non-profit organization
  dedicated to making software imaging solutions freely available.

  You may not use this file except in compliance with the License.
  obtain a copy of the License at

    http://www.wizards-toolkit.org/script/license.php

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

  Wizard's Toolkit private methods to lock and unlock semaphores.
*/
#ifndef _WIZARDSTOOLKIT_SEMAPHORE_PRIVATE_H
#define _WIZARDSTOOLKIT_SEMAPHORE_PRIVATE_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#include "wizard/exception-private.h"

#if defined(WIZARDSTOOLKIT_HAVE_PTHREAD)
static pthread_mutex_t
  semaphore_mutex = PTHREAD_MUTEX_INITIALIZER;
#elif defined(WIZARDSTOOLKIT_HAVE_WINTHREADS)
static LONG
  semaphore_mutex = 0;
#else
static ssize_t
  semaphore_mutex = 0;
#endif

static inline void LockWizardMutex(void)
{
#if defined(WIZARDSTOOLKIT_HAVE_PTHREAD)
  {
    int
      status;

    status=pthread_mutex_lock(&semaphore_mutex);
    if (status != 0)
      { 
        errno=status;
        ThrowFatalException(ResourceFatalError,
          "unable to lock semaphore `%s'");
      }
  }
#elif defined(WIZARDSTOOLKIT_HAVE_WINTHREADS)
  while (InterlockedCompareExchange(&semaphore_mutex,1L,0L) != 0)
    Sleep(10);
#endif
}

static inline void UnlockWizardMutex(void)
{
#if defined(WIZARDSTOOLKIT_HAVE_PTHREAD)
  {
    int
      status;

    status=pthread_mutex_unlock(&semaphore_mutex);
    if (status != 0)
      {
        errno=status;
        ThrowFatalException(ResourceFatalError,
          "unable to unlock semaphore `%s'");
      }
  }
#elif defined(WIZARDSTOOLKIT_HAVE_WINTHREADS)
  InterlockedExchange(&semaphore_mutex,0L);
#endif
}

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#endif