1 /* Copyright (C) 2005, 2006 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU OpenMP Library (libgomp). 5 6 Libgomp is free software; you can redistribute it and/or modify it 7 under the terms of the GNU Lesser General Public License as published by 8 the Free Software Foundation; either version 2.1 of the License, or 9 (at your option) any later version. 10 11 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 13 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 14 more details. 15 16 You should have received a copy of the GNU Lesser General Public License 17 along with libgomp; see the file COPYING.LIB. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 19 MA 02110-1301, USA. */ 20 21 /* As a special exception, if you link this library with other files, some 22 of which are compiled with GCC, to produce an executable, this library 23 does not by itself cause the resulting executable to be covered by the 24 GNU General Public License. This exception does not however invalidate 25 any other reasons why the executable file might be covered by the GNU 26 General Public License. */ 27 28 /* This is the default POSIX 1003.1b implementation of a semaphore 29 synchronization mechanism for libgomp. This type is private to 30 the library. 31 32 This is a bit heavy weight for what we need, in that we're not 33 interested in sem_wait as a cancelation point, but it's not too 34 bad for a default. */ 35 36 #include "libgomp.h" 37 38 #ifdef HAVE_BROKEN_POSIX_SEMAPHORES 39 #include <stdlib.h> 40 41 void gomp_sem_init (gomp_sem_t *sem, int value) 42 { 43 int ret; 44 45 ret = pthread_mutex_init (&sem->mutex, NULL); 46 if (ret) 47 return; 48 49 ret = pthread_cond_init (&sem->cond, NULL); 50 if (ret) 51 return; 52 53 sem->value = value; 54 } 55 56 void gomp_sem_wait (gomp_sem_t *sem) 57 { 58 int ret; 59 60 ret = pthread_mutex_lock (&sem->mutex); 61 if (ret) 62 return; 63 64 if (sem->value > 0) 65 { 66 sem->value--; 67 ret = pthread_mutex_unlock (&sem->mutex); 68 return; 69 } 70 71 while (sem->value <= 0) 72 { 73 ret = pthread_cond_wait (&sem->cond, &sem->mutex); 74 if (ret) 75 { 76 pthread_mutex_unlock (&sem->mutex); 77 return; 78 } 79 } 80 81 sem->value--; 82 ret = pthread_mutex_unlock (&sem->mutex); 83 return; 84 } 85 86 void gomp_sem_post (gomp_sem_t *sem) 87 { 88 int ret; 89 90 ret = pthread_mutex_lock (&sem->mutex); 91 if (ret) 92 return; 93 94 sem->value++; 95 96 ret = pthread_mutex_unlock (&sem->mutex); 97 if (ret) 98 return; 99 100 ret = pthread_cond_signal (&sem->cond); 101 102 return; 103 } 104 105 void gomp_sem_destroy (gomp_sem_t *sem) 106 { 107 int ret; 108 109 ret = pthread_mutex_destroy (&sem->mutex); 110 if (ret) 111 return; 112 113 ret = pthread_cond_destroy (&sem->cond); 114 115 return; 116 } 117 #else /* HAVE_BROKEN_POSIX_SEMAPHORES */ 118 void 119 gomp_sem_wait (gomp_sem_t *sem) 120 { 121 /* With POSIX, the wait can be canceled by signals. We don't want that. 122 It is expected that the return value here is -1 and errno is EINTR. */ 123 while (sem_wait (sem) != 0) 124 continue; 125 } 126 #endif 127