text: /*
   * pthread_mutex_unlock.c
   *
   * Description:
   * This translation unit implements mutual exclusion (mutex) primitives.
   *
   * --------------------------------------------------------------------------
   *
   *      Pthreads-win32 - POSIX Threads Library for Win32
   *      Copyright(C) 1998 John E. Bossom
   *      Copyright(C) 1999,2005 Pthreads-win32 contributors
   * 
   *      Contact Email: rpj@callisto.canberra.edu.au
   * 
   *      The current list of contributors is contained
   *      in the file CONTRIBUTORS included with the source
   *      code distribution. The list can also be seen at the
   *      following World Wide Web location:
   *      http://sources.redhat.com/pthreads-win32/contributors.html
   * 
   *      This library is free software; you can redistribute it and/or
   *      modify it under the terms of the GNU Lesser General Public
   *      License as published by the Free Software Foundation; either
   *      version 2 of the License, or (at your option) any later version.
   * 
   *      This library is distributed in the hope that it will be useful,
   *      but WITHOUT ANY WARRANTY; without even the implied warranty of
   *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *      Lesser General Public License for more details.
   * 
   *      You should have received a copy of the GNU Lesser General Public
   *      License along with this library in the file COPYING.LIB;
   *      if not, write to the Free Software Foundation, Inc.,
   *      51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
   */
  
  #include "pthread.h"
  #include "implement.h"
  
  
  int
  pthread_mutex_unlock (pthread_mutex_t * mutex)
  {
    int result = 0;
    int kind;
    pthread_mutex_t mx;
  
    /*
     * Let the system deal with invalid pointers.
     */
  
    mx = *mutex;
  
    /*
     * If the thread calling us holds the mutex then there is no
     * race condition. If another thread holds the
     * lock then we shouldn't be in here.
     */
    if (mx < PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
      {
        kind = mx->kind;
  
        if (kind >= 0)
          {
            if (kind == PTHREAD_MUTEX_NORMAL)
  	    {
  	      LONG idx;
  
  	      idx = (LONG) PTW32_INTERLOCKED_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR)&mx->lock_idx,
  							    (PTW32_INTERLOCKED_LONG)0);
  	      if (idx != 0)
  	        {
  	          if (idx < 0)
  		    {
  		      /*
  		       * Someone may be waiting on that mutex.
  		       */
  		      if (SetEvent (mx->event) == 0)
  		        {
  		          result = EINVAL;
  		        }
  		    }
  	        }
  	    }
            else
  	    {
  	      if (pthread_equal (mx->ownerThread, pthread_self()))
  	        {
  	          if (kind != PTHREAD_MUTEX_RECURSIVE
  		      || 0 == --mx->recursive_count)
  		    {
  		      mx->ownerThread.p = NULL;
  
  		      if ((LONG) PTW32_INTERLOCKED_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR)&mx->lock_idx,
  							          (PTW32_INTERLOCKED_LONG)0) < 0L)
  		        {
  		          /* Someone may be waiting on that mutex */
  		          if (SetEvent (mx->event) == 0)
  			    {
  			      result = EINVAL;
  			    }
  		        }
  		    }
  	        }
  	      else
  	        {
  	          result = EPERM;
  	        }
  	    }
          }
        else
          {
            /* Robust types */
            pthread_t self = pthread_self();
            kind = -kind - 1; /* Convert to non-robust range */
  
            /*
             * The thread must own the lock regardless of type if the mutex
             * is robust.
             */
            if (pthread_equal (mx->ownerThread, self))
              {
                PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG((PTW32_INTERLOCKED_LONGPTR) &mx->robustNode->stateInconsistent,
                                                        (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_NOTRECOVERABLE,
                                                        (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_INCONSISTENT);
                if (PTHREAD_MUTEX_NORMAL == kind)
                  {
                    ptw32_robust_mutex_remove(mutex, NULL);
  
                    if ((LONG) PTW32_INTERLOCKED_EXCHANGE_LONG((PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx,
                                                               (PTW32_INTERLOCKED_LONG) 0) < 0)
                      {
                        /*
                         * Someone may be waiting on that mutex.
                         */
                        if (SetEvent (mx->event) == 0)
                          {
                            result = EINVAL;
                          }
                      }
                  }
                else
                  {
                    if (kind != PTHREAD_MUTEX_RECURSIVE
                        || 0 == --mx->recursive_count)
                      {
                        ptw32_robust_mutex_remove(mutex, NULL);
  
                        if ((LONG) PTW32_INTERLOCKED_EXCHANGE_LONG((PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx,
                                                                   (PTW32_INTERLOCKED_LONG) 0) < 0)
                          {
                            /*
                             * Someone may be waiting on that mutex.
                             */
                            if (SetEvent (mx->event) == 0)
                              {
                                result = EINVAL;
                              }
                          }
                      }
                  }
              }
            else
              {
                result = EPERM;
              }
          }
      }
    else if (mx != PTHREAD_MUTEX_INITIALIZER)
      {
        result = EINVAL;
      }
  
    return (result);
  }
  