native_client_sdk/src/libraries/third_party/pthreads-win32/pthread_mutexattr_getrobust.c

   1 /*
   2  * pthread_mutexattr_getrobust.c
   3  *
   4  * Description:
   5  * This translation unit implements mutual exclusion (mutex) primitives.
   6  *
   7  * --------------------------------------------------------------------------
   8  *
   9  *      Pthreads-win32 - POSIX Threads Library for Win32
  10  *      Copyright(C) 1998 John E. Bossom
  11  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  12  *
  13  *      Contact Email: rpj@callisto.canberra.edu.au
  14  *
  15  *      The current list of contributors is contained
  16  *      in the file CONTRIBUTORS included with the source
  17  *      code distribution. The list can also be seen at the
  18  *      following World Wide Web location:
  19  *      http://sources.redhat.com/pthreads-win32/contributors.html
  20  *
  21  *      This library is free software; you can redistribute it and/or
  22  *      modify it under the terms of the GNU Lesser General Public
  23  *      License as published by the Free Software Foundation; either
  24  *      version 2 of the License, or (at your option) any later version.
  25  *
  26  *      This library is distributed in the hope that it will be useful,
  27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  29  *      Lesser General Public License for more details.
  30  *
  31  *      You should have received a copy of the GNU Lesser General Public
  32  *      License along with this library in the file COPYING.LIB;
  33  *      if not, write to the Free Software Foundation, Inc.,
  34  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  35  */
  36
  37 #include "pthread.h"
  38 #include "implement.h"
  39
  40
  41 int
  42 pthread_mutexattr_getrobust (const pthread_mutexattr_t * attr, int * robust)
  43      /*
  44       * ------------------------------------------------------
  45       *
  46       * DOCPUBLIC
  47       * The pthread_mutexattr_setrobust() and
  48       * pthread_mutexattr_getrobust() functions  respectively set and
  49       * get the mutex robust  attribute. This attribute is set in  the
  50       * robust parameter to these functions.
  51       *
  52       * PARAMETERS
  53       *      attr
  54       *              pointer to an instance of pthread_mutexattr_t
  55       *
  56       *     robust
  57       *              must be one of:
  58       *
  59       *                      PTHREAD_MUTEX_STALLED
  60       *
  61       *                      PTHREAD_MUTEX_ROBUST
  62       *
  63       * DESCRIPTION
  64       * The pthread_mutexattr_setrobust() and
  65       * pthread_mutexattr_getrobust() functions  respectively set and
  66       * get the mutex robust  attribute. This attribute is set in  the
  67       * robust  parameter to these functions. The default value of the
  68       * robust  attribute is  PTHREAD_MUTEX_STALLED.
  69       *
  70       * The robustness of mutex is contained in the robustness attribute
  71       * of the mutex attributes. Valid mutex robustness values are:
  72       *
  73       * PTHREAD_MUTEX_STALLED
  74       * No special actions are taken if the owner of the mutex is
  75       * terminated while holding the mutex lock. This can lead to
  76       * deadlocks if no other thread can unlock the mutex.
  77       * This is the default value.
  78       *
  79       * PTHREAD_MUTEX_ROBUST
  80       * If the process containing the owning thread of a robust mutex
  81       * terminates while holding the mutex lock, the next thread that
  82       * acquires the mutex shall be notified about the termination by
  83       * the return value [EOWNERDEAD] from the locking function. If the
  84       * owning thread of a robust mutex terminates while holding the mutex
  85       * lock, the next thread that acquires the mutex may be notified
  86       * about the termination by the return value [EOWNERDEAD]. The
  87       * notified thread can then attempt to mark the state protected by
  88       * the mutex as consistent again by a call to
  89       * pthread_mutex_consistent(). After a subsequent successful call to
  90       * pthread_mutex_unlock(), the mutex lock shall be released and can
  91       * be used normally by other threads. If the mutex is unlocked without
  92       * a call to pthread_mutex_consistent(), it shall be in a permanently
  93       * unusable state and all attempts to lock the mutex shall fail with
  94       * the error [ENOTRECOVERABLE]. The only permissible operation on such
  95       * a mutex is pthread_mutex_destroy().
  96       *
  97       * RESULTS
  98       *              0               successfully set attribute,
  99       *              EINVAL          'attr' or 'robust' is invalid,
 100       *
 101       * ------------------------------------------------------
 102       */
 103 {
 104   int result = EINVAL;
 105
 106   if ((attr != NULL && *attr != NULL && robust != NULL))
 107     {
 108       *robust = (*attr)->robustness;
 109       result = 0;
 110     }
 111
 112   return (result);
 113 }                               /* pthread_mutexattr_getrobust */