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

   1 /*
   2  * pthread_cond_init.c
   3  *
   4  * Description:
   5  * This translation unit implements condition variables and their primitives.
   6  *
   7  *
   8  * --------------------------------------------------------------------------
   9  *
  10  *      Pthreads-win32 - POSIX Threads Library for Win32
  11  *      Copyright(C) 1998 John E. Bossom
  12  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  13  *
  14  *      Contact Email: rpj@callisto.canberra.edu.au
  15  *
  16  *      The current list of contributors is contained
  17  *      in the file CONTRIBUTORS included with the source
  18  *      code distribution. The list can also be seen at the
  19  *      following World Wide Web location:
  20  *      http://sources.redhat.com/pthreads-win32/contributors.html
  21  *
  22  *      This library is free software; you can redistribute it and/or
  23  *      modify it under the terms of the GNU Lesser General Public
  24  *      License as published by the Free Software Foundation; either
  25  *      version 2 of the License, or (at your option) any later version.
  26  *
  27  *      This library is distributed in the hope that it will be useful,
  28  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  30  *      Lesser General Public License for more details.
  31  *
  32  *      You should have received a copy of the GNU Lesser General Public
  33  *      License along with this library in the file COPYING.LIB;
  34  *      if not, write to the Free Software Foundation, Inc.,
  35  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  36  */
  37
  38 #include "pthread.h"
  39 #include "implement.h"
  40
  41
  42 int
  43 pthread_cond_init (pthread_cond_t * cond, const pthread_condattr_t * attr)
  44      /*
  45       * ------------------------------------------------------
  46       * DOCPUBLIC
  47       *      This function initializes a condition variable.
  48       *
  49       * PARAMETERS
  50       *      cond
  51       *              pointer to an instance of pthread_cond_t
  52       *
  53       *      attr
  54       *              specifies optional creation attributes.
  55       *
  56       *
  57       * DESCRIPTION
  58       *      This function initializes a condition variable.
  59       *
  60       * RESULTS
  61       *              0               successfully created condition variable,
  62       *              EINVAL          'attr' is invalid,
  63       *              EAGAIN          insufficient resources (other than
  64       *                              memory,
  65       *              ENOMEM          insufficient memory,
  66       *              EBUSY           'cond' is already initialized,
  67       *
  68       * ------------------------------------------------------
  69       */
  70 {
  71   int result;
  72   pthread_cond_t cv = NULL;
  73
  74   if (cond == NULL)
  75     {
  76       return EINVAL;
  77     }
  78
  79   if ((attr != NULL && *attr != NULL) &&
  80       ((*attr)->pshared == PTHREAD_PROCESS_SHARED))
  81     {
  82       /*
  83        * Creating condition variable that can be shared between
  84        * processes.
  85        */
  86       result = ENOSYS;
  87       goto DONE;
  88     }
  89
  90   cv = (pthread_cond_t) calloc (1, sizeof (*cv));
  91
  92   if (cv == NULL)
  93     {
  94       result = ENOMEM;
  95       goto DONE;
  96     }
  97
  98   cv->nWaitersBlocked = 0;
  99   cv->nWaitersToUnblock = 0;
 100   cv->nWaitersGone = 0;
 101
 102   if (sem_init (&(cv->semBlockLock), 0, 1) != 0)
 103     {
 104       result = errno;
 105       goto FAIL0;
 106     }
 107
 108   if (sem_init (&(cv->semBlockQueue), 0, 0) != 0)
 109     {
 110       result = errno;
 111       goto FAIL1;
 112     }
 113
 114   if ((result = pthread_mutex_init (&(cv->mtxUnblockLock), 0)) != 0)
 115     {
 116       goto FAIL2;
 117     }
 118
 119   result = 0;
 120
 121   goto DONE;
 122
 123   /*
 124    * -------------
 125    * Failed...
 126    * -------------
 127    */
 128 FAIL2:
 129   (void) sem_destroy (&(cv->semBlockQueue));
 130
 131 FAIL1:
 132   (void) sem_destroy (&(cv->semBlockLock));
 133
 134 FAIL0:
 135   (void) free (cv);
 136   cv = NULL;
 137
 138 DONE:
 139   if (0 == result)
 140     {
 141       ptw32_mcs_local_node_t node;
 142
 143       ptw32_mcs_lock_acquire(&ptw32_cond_list_lock, &node);
 144
 145       cv->next = NULL;
 146       cv->prev = ptw32_cond_list_tail;
 147
 148       if (ptw32_cond_list_tail != NULL)
 149         {
 150           ptw32_cond_list_tail->next = cv;
 151         }
 152
 153       ptw32_cond_list_tail = cv;
 154
 155       if (ptw32_cond_list_head == NULL)
 156         {
 157           ptw32_cond_list_head = cv;
 158         }
 159
 160       ptw32_mcs_lock_release(&node);
 161     }
 162
 163   *cond = cv;
 164
 165   return result;
 166
 167 }                               /* pthread_cond_init */