pthread_rwlock_init.c

/*
 * pthread_rwlock_init.c
 *
 * Description:
 * This translation unit implements read/write lock primitives.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads4w - POSIX Threads for Windows
 *      Copyright 1998 John E. Bossom
 *      Copyright 1999-2018, Pthreads4w contributors
 *
 *      Homepage: https://sourceforge.net/projects/pthreads4w/
 *
 *      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:
 *
 *      https://sourceforge.net/p/pthreads4w/wiki/Contributors/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <limits.h>

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

int
pthread_rwlock_init (pthread_rwlock_t * rwlock,
		     const pthread_rwlockattr_t * attr)
{
  int result;
  pthread_rwlock_t rwl = 0;

  if (rwlock == NULL)
    {
      return EINVAL;
    }

  if (attr != NULL && *attr != NULL)
    {
      result = EINVAL;		/* Not supported */
      goto DONE;
    }

  rwl = (pthread_rwlock_t) calloc (1, sizeof (*rwl));

  if (rwl == NULL)
    {
      result = ENOMEM;
      goto DONE;
    }

  rwl->nSharedAccessCount = 0;
  rwl->nExclusiveAccessCount = 0;
  rwl->nCompletedSharedAccessCount = 0;

  result = pthread_mutex_init (&rwl->mtxExclusiveAccess, NULL);
  if (result != 0)
    {
      goto FAIL0;
    }

  result = pthread_mutex_init (&rwl->mtxSharedAccessCompleted, NULL);
  if (result != 0)
    {
      goto FAIL1;
    }

  result = pthread_cond_init (&rwl->cndSharedAccessCompleted, NULL);
  if (result != 0)
    {
      goto FAIL2;
    }

  rwl->nMagic =  __PTW32_RWLOCK_MAGIC;

  result = 0;
  goto DONE;

FAIL2:
  (void) pthread_mutex_destroy (&(rwl->mtxSharedAccessCompleted));

FAIL1:
  (void) pthread_mutex_destroy (&(rwl->mtxExclusiveAccess));

FAIL0:
  (void) free (rwl);
  rwl = NULL;

DONE:
  *rwlock = rwl;

  return result;
}