pthread_barrier_destroy.c

/*
 * pthread_barrier_destroy.c
 *
 * Description:
 * This translation unit implements barrier 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.,
 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include "pthread.h"
#include "implement.h"

int
pthread_barrier_destroy (pthread_barrier_t * barrier)
{
  int result = 0;
  pthread_barrier_t b;
  ptw32_mcs_local_node_t node;

  if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)
    {
      return EINVAL;
    }

  if (0 != ptw32_mcs_lock_try_acquire(&(*barrier)->lock, &node))
    {
      return EBUSY;
    }

  b = *barrier;

  if (b->nCurrentBarrierHeight < b->nInitialBarrierHeight)
    {
      result = EBUSY;
    }
  else
	{
      if (0 == (result = sem_destroy (&(b->semBarrierBreeched))))
        {
          *barrier = (pthread_barrier_t) PTW32_OBJECT_INVALID;
          /*
           * Release the lock before freeing b.
           *
           * FIXME: There may be successors which, when we release the lock,
           * will be linked into b->lock, which will be corrupted at some
           * point with undefined results for the application. To fix this
           * will require changing pthread_barrier_t from a pointer to
           * pthread_barrier_t_ to an instance. This is a change to the ABI
           * and will require a major version number increment.
           */
          ptw32_mcs_lock_release(&node);
	  (void) free (b);
	  return 0;
	}
      else
        {
          /*
           * This should not ever be reached.
           * Restore the barrier to working condition before returning.
           */
          (void) sem_init (&(b->semBarrierBreeched), b->pshared, 0);
        }

      if (result != 0)
        {
          /*
           * The barrier still exists and is valid
           * in the event of any error above.
           */
          result = EBUSY;
        }
    }

  ptw32_mcs_lock_release(&node);
  return (result);
}