1 /* Signal a condition. Generic version. 2 Copyright (C) 2000-2022 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 <https://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 __pthread_cond_signal(pthread_cond_t * cond)26__pthread_cond_signal (pthread_cond_t *cond) 27 { 28 struct __pthread *wakeup; 29 30 __pthread_spin_wait (&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 weak_alias (__pthread_cond_signal, pthread_cond_signal); 43