pthread_mutexattr_getrobust.c

/*
 * pthread_mutexattr_getrobust.c
 *
 * Description:
 * This translation unit implements mutual exclusion (mutex) primitives.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads-win32 - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999,2012 Pthreads-win32 contributors
 *
 *      Homepage1: http://sourceware.org/pthreads-win32/
 *      Homepage2: http://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:
 *      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
 */

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

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


int
pthread_mutexattr_getrobust (const pthread_mutexattr_t * attr, int * robust)
     /*
      * ------------------------------------------------------
      *
      * DOCPUBLIC
      * The pthread_mutexattr_setrobust() and
      * pthread_mutexattr_getrobust() functions  respectively set and
      * get the mutex robust  attribute. This attribute is set in  the
      * robust parameter to these functions.
      *
      * PARAMETERS
      *      attr
      *              pointer to an instance of pthread_mutexattr_t
      *
      *     robust 
      *              must be one of:
      *
      *                      PTHREAD_MUTEX_STALLED
      *
      *                      PTHREAD_MUTEX_ROBUST
      *
      * DESCRIPTION
      * The pthread_mutexattr_setrobust() and
      * pthread_mutexattr_getrobust() functions  respectively set and
      * get the mutex robust  attribute. This attribute is set in  the
      * robust  parameter to these functions. The default value of the
      * robust  attribute is  PTHREAD_MUTEX_STALLED.
      * 
      * The robustness of mutex is contained in the robustness attribute
      * of the mutex attributes. Valid mutex robustness values are:
      *
      * PTHREAD_MUTEX_STALLED
      * No special actions are taken if the owner of the mutex is
      * terminated while holding the mutex lock. This can lead to
      * deadlocks if no other thread can unlock the mutex.
      * This is the default value.
      * 
      * PTHREAD_MUTEX_ROBUST
      * If the process containing the owning thread of a robust mutex
      * terminates while holding the mutex lock, the next thread that
      * acquires the mutex shall be notified about the termination by
      * the return value [EOWNERDEAD] from the locking function. If the
      * owning thread of a robust mutex terminates while holding the mutex
      * lock, the next thread that acquires the mutex may be notified
      * about the termination by the return value [EOWNERDEAD]. The
      * notified thread can then attempt to mark the state protected by
      * the mutex as consistent again by a call to
      * pthread_mutex_consistent(). After a subsequent successful call to
      * pthread_mutex_unlock(), the mutex lock shall be released and can
      * be used normally by other threads. If the mutex is unlocked without
      * a call to pthread_mutex_consistent(), it shall be in a permanently
      * unusable state and all attempts to lock the mutex shall fail with
      * the error [ENOTRECOVERABLE]. The only permissible operation on such
      * a mutex is pthread_mutex_destroy().
      *
      * RESULTS
      *              0               successfully set attribute,
      *              EINVAL          'attr' or 'robust' is invalid,
      *
      * ------------------------------------------------------
      */
{
  int result = EINVAL;

  if ((attr != NULL && *attr != NULL && robust != NULL))
    {
      *robust = (*attr)->robustness;
      result = 0;
    }

  return (result);
}				/* pthread_mutexattr_getrobust */