sysdeps/htl/pt-cond-signal.c

   1 /* Signal a condition.  Generic version.
   2    Copyright (C) 2000-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <pthread.h>
  20
  21 #include <pt-internal.h>
  22
  23 /* Unblock at least one of the threads that are blocked on condition
  24    variable COND.  */
  25 int
  26 __pthread_cond_signal (pthread_cond_t *cond)
  27 {
  28   struct __pthread *wakeup;
  29
  30   __pthread_spin_lock (&cond->__lock);
  31   wakeup = cond->__queue;
  32   if (wakeup != NULL)
  33     __pthread_dequeue (wakeup);
  34   __pthread_spin_unlock (&cond->__lock);
  35
  36   if (wakeup != NULL)
  37     __pthread_wakeup (wakeup);
  38
  39   return 0;
  40 }
  41
  42 strong_alias (__pthread_cond_signal, pthread_cond_signal);