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

   1 /*
   2  * -------------------------------------------------------------
   3  *
   4  * Module: sem_getvalue.c
   5  *
   6  * Purpose:
   7  *      Semaphores aren't actually part of PThreads.
   8  *      They are defined by the POSIX Standard:
   9  *
  10  *              POSIX 1003.1-2001
  11  *
  12  * -------------------------------------------------------------
  13  *
  14  * --------------------------------------------------------------------------
  15  *
  16  *      Pthreads-win32 - POSIX Threads Library for Win32
  17  *      Copyright(C) 1998 John E. Bossom
  18  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  19  *
  20  *      Contact Email: rpj@callisto.canberra.edu.au
  21  *
  22  *      The current list of contributors is contained
  23  *      in the file CONTRIBUTORS included with the source
  24  *      code distribution. The list can also be seen at the
  25  *      following World Wide Web location:
  26  *      http://sources.redhat.com/pthreads-win32/contributors.html
  27  *
  28  *      This library is free software; you can redistribute it and/or
  29  *      modify it under the terms of the GNU Lesser General Public
  30  *      License as published by the Free Software Foundation; either
  31  *      version 2 of the License, or (at your option) any later version.
  32  *
  33  *      This library is distributed in the hope that it will be useful,
  34  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  35  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  36  *      Lesser General Public License for more details.
  37  *
  38  *      You should have received a copy of the GNU Lesser General Public
  39  *      License along with this library in the file COPYING.LIB;
  40  *      if not, write to the Free Software Foundation, Inc.,
  41  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  42  */
  43
  44 #include "pthread.h"
  45 #include "semaphore.h"
  46 #include "implement.h"
  47
  48
  49 int
  50 sem_getvalue (sem_t * sem, int *sval)
  51      /*
  52       * ------------------------------------------------------
  53       * DOCPUBLIC
  54       *      This function stores the current count value of the
  55       *      semaphore.
  56       * RESULTS
  57       *
  58       * Return value
  59       *
  60       *       0                  sval has been set.
  61       *      -1                  failed, error in errno
  62       *
  63       *  in global errno
  64       *
  65       *      EINVAL              'sem' is not a valid semaphore,
  66       *      ENOSYS              this function is not supported,
  67       *
  68       *
  69       * PARAMETERS
  70       *
  71       *      sem                 pointer to an instance of sem_t
  72       *
  73       *      sval                pointer to int.
  74       *
  75       * DESCRIPTION
  76       *      This function stores the current count value of the semaphore
  77       *      pointed to by sem in the int pointed to by sval.
  78       */
  79 {
  80   if (sem == NULL || *sem == NULL || sval == NULL)
  81     {
  82       errno = EINVAL;
  83       return -1;
  84     }
  85   else
  86     {
  87       long value;
  88       register sem_t s = *sem;
  89       int result = 0;
  90
  91       if ((result = pthread_mutex_lock(&s->lock)) == 0)
  92         {
  93           /* See sem_destroy.c
  94            */
  95           if (*sem == NULL)
  96             {
  97               (void) pthread_mutex_unlock (&s->lock);
  98               errno = EINVAL;
  99               return -1;
 100             }
 101
 102           value = s->value;
 103           (void) pthread_mutex_unlock(&s->lock);
 104           *sval = value;
 105         }
 106
 107       return result;
 108     }
 109
 110 }                               /* sem_getvalue */