pthread_rwlockattr_getpshared.c

/*
 * pthread_rwlockattr_getpshared.c
 *
 * Description:
 * This translation unit implements read/write lock 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 <limits.h>

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

int
pthread_rwlockattr_getpshared (const pthread_rwlockattr_t * attr,
			       int *pshared)
     /*
      * ------------------------------------------------------
      * DOCPUBLIC
      *      Determine whether rwlocks created with 'attr' can be
      *      shared between processes.
      *
      * PARAMETERS
      *      attr
      *              pointer to an instance of pthread_rwlockattr_t
      *
      *      pshared
      *              will be set to one of:
      *
      *                      PTHREAD_PROCESS_SHARED
      *                              May be shared if in shared memory
      *
      *                      PTHREAD_PROCESS_PRIVATE
      *                              Cannot be shared.
      *
      *
      * DESCRIPTION
      *      Rwlocks creatd with 'attr' can be shared between
      *      processes if pthread_rwlock_t variable is allocated
      *      in memory shared by these processes.
      *      NOTES:
      *              1)      pshared rwlocks MUST be allocated in shared
      *                      memory.
      *              2)      The following macro is defined if shared rwlocks
      *                      are supported:
      *                              _POSIX_THREAD_PROCESS_SHARED
      *
      * RESULTS
      *              0               successfully retrieved attribute,
      *              EINVAL          'attr' is invalid,
      *
      * ------------------------------------------------------
      */
{
  int result;

  if ((attr != NULL && *attr != NULL) && (pshared != NULL))
    {
      *pshared = (*attr)->pshared;
      result = 0;
    }
  else
    {
      result = EINVAL;
    }

  return (result);

}				/* pthread_rwlockattr_getpshared */