text: /*
   * -------------------------------------------------------------
   *
   * Module: sem_post_multiple.c
   *
   * Purpose:
   *	Semaphores aren't actually part of the PThreads standard.
   *	They are defined by the POSIX Standard:
   *
   *		POSIX 1003.1b-1993	(POSIX.1b)
   *
   * -------------------------------------------------------------
   *
   * --------------------------------------------------------------------------
   *
   *      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.,
   *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
   */
  
  #include "pthread.h"
  #include "semaphore.h"
  #include "implement.h"
  
  
  int
  sem_post_multiple (sem_t * sem, int count)
       /*
        * ------------------------------------------------------
        * DOCPUBLIC
        *      This function posts multiple wakeups to a semaphore.
        *
        * PARAMETERS
        *      sem
        *              pointer to an instance of sem_t
        *
        *      count
        *              counter, must be greater than zero.
        *
        * DESCRIPTION
        *      This function posts multiple wakeups to a semaphore. If there
        *      are waiting threads (or processes), n <= count are awakened;
        *      the semaphore value is incremented by count - n.
        *
        * RESULTS
        *              0               successfully posted semaphore,
        *              -1              failed, error in errno
        * ERRNO
        *              EINVAL          'sem' is not a valid semaphore
        *                              or count is less than or equal to zero.
        *              ERANGE          semaphore count is too big
        *
        * ------------------------------------------------------
        */
  {
    int result = 0;
    long waiters;
    sem_t s = *sem;
  
    if (s == NULL || count <= 0)
      {
        result = EINVAL;
      }
    else if ((result = pthread_mutex_lock (&s->lock)) == 0)
      {
        /* See sem_destroy.c
         */
        if (*sem == NULL)
          {
            (void) pthread_mutex_unlock (&s->lock);
            result = EINVAL;
            return -1;
          }
  
        if (s->value <= (SEM_VALUE_MAX - count))
  	{
  	  waiters = -s->value;
  	  s->value += count;
  	  if (waiters > 0)
  	    {
  #if defined(NEED_SEM)
  	      if (SetEvent(s->sem))
  		{
  		  waiters--;
  		  s->leftToUnblock += count - 1;
  		  if (s->leftToUnblock > waiters)
  		    {
  		      s->leftToUnblock = waiters;
  		    }
  		}
  #else
  	      if (ReleaseSemaphore (s->sem,  (waiters<=count)?waiters:count, 0))
  		{
  		  /* No action */
  		}
  #endif
  	      else
  		{
  		  s->value -= count;
  		  result = EINVAL;
  		}
  	    }
  	}
        else
  	{
  	  result = ERANGE;
  	}
        (void) pthread_mutex_unlock (&s->lock);
      }
  
    if (result != 0)
      {
        errno = result;
        return -1;
      }
  
    return 0;
  
  }				/* sem_post_multiple */
  