xref: /relibc/pthreads-emb/pthread_rwlockattr_setpshared.c (revision 062c5bc4dfeed2c1bed58ed4810dd27adb32c68d)

/*
 * pthread_rwlockattr_setpshared.c
 *
 * Description:
 * This translation unit implements read/write lock primitives.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
 *      Copyright(C) 2008 Jason Schmidlapp
 *
 *      Contact Email: jschmidlapp@users.sourceforge.net
 *
 *
 *      Based upon 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 original list of contributors to the Pthreads-win32 project
 *      is contained in the file CONTRIBUTORS.ptw32 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 <errno.h>
#include <limits.h>

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

int
pthread_rwlockattr_setpshared (pthread_rwlockattr_t * attr, int pshared)
/*
 * ------------------------------------------------------
 * DOCPUBLIC
 *      Rwlocks created with 'attr' can be shared between
 *      processes if pthread_rwlock_t variable is allocated
 *      in memory shared by these processes.
 *
 * PARAMETERS
 *      attr
 *              pointer to an instance of pthread_rwlockattr_t
 *
 *      pshared
 *              must be 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 set attribute,
 *              EINVAL          'attr' or pshared is invalid,
 *              ENOSYS          PTHREAD_PROCESS_SHARED not supported,
 *
 * ------------------------------------------------------
 */
{
  int result;

  if ((attr != NULL && *attr != NULL) &&
      ((pshared == PTHREAD_PROCESS_SHARED) ||
       (pshared == PTHREAD_PROCESS_PRIVATE)))
    {
      if (pshared == PTHREAD_PROCESS_SHARED)
        {

#if !defined( _POSIX_THREAD_PROCESS_SHARED )

          result = ENOSYS;
          pshared = PTHREAD_PROCESS_PRIVATE;

#else

          result = 0;

#endif /* _POSIX_THREAD_PROCESS_SHARED */

        }
      else
        {
          result = 0;
        }

      (*attr)->pshared = pshared;
    }
  else
    {
      result = EINVAL;
    }

  return (result);

}				/* pthread_rwlockattr_setpshared */