nptl/old_pthread_cond_wait.c

   1 /* Copyright (C) 2002-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <stdlib.h>
  21 #include "pthreadP.h"
  22 #include <atomic.h>
  23 #include <shlib-compat.h>
  24
  25
  26 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
  27 int
  28 __pthread_cond_wait_2_0 (pthread_cond_2_0_t *cond, pthread_mutex_t *mutex)
  29 {
  30   if (cond->cond == NULL)
  31     {
  32       pthread_cond_t *newcond;
  33
  34 #if LLL_LOCK_INITIALIZER == 0
  35       newcond = (pthread_cond_t *) calloc (sizeof (pthread_cond_t), 1);
  36       if (newcond == NULL)
  37         return ENOMEM;
  38 #else
  39       newcond = (pthread_cond_t *) malloc (sizeof (pthread_cond_t));
  40       if (newcond == NULL)
  41         return ENOMEM;
  42
  43       /* Initialize the condvar.  */
  44       (void) pthread_cond_init (newcond, NULL);
  45 #endif
  46
  47       if (atomic_compare_and_exchange_bool_acq (&cond->cond, newcond, NULL))
  48         /* Somebody else just initialized the condvar.  */
  49         free (newcond);
  50     }
  51
  52   return __pthread_cond_wait (cond->cond, mutex);
  53 }
  54 compat_symbol (libpthread, __pthread_cond_wait_2_0, pthread_cond_wait,
  55                GLIBC_2_0);
  56 #endif