1 #ifndef GC_DARWIN_SEMAPHORE_H
2 #define GC_DARWIN_SEMAPHORE_H
4 #if !defined(GC_DARWIN_THREADS)
5 #error darwin_semaphore.h included with GC_DARWIN_THREADS not defined
9 This is a very simple semaphore implementation for darwin. It
10 is implemented in terms of pthreads calls so it isn't async signal
11 safe. This isn't a problem because signals aren't used to
12 suspend threads on darwin.
16 pthread_mutex_t mutex;
21 static int sem_init(sem_t *sem, int pshared, int value) {
24 GC_abort("sem_init with pshared set");
27 ret = pthread_mutex_init(&sem->mutex,NULL);
28 if(ret < 0) return -1;
29 ret = pthread_cond_init(&sem->cond,NULL);
30 if(ret < 0) return -1;
34 static int sem_post(sem_t *sem) {
35 if(pthread_mutex_lock(&sem->mutex) < 0)
38 if(pthread_cond_signal(&sem->cond) < 0) {
39 pthread_mutex_unlock(&sem->mutex);
42 if(pthread_mutex_unlock(&sem->mutex) < 0)
47 static int sem_wait(sem_t *sem) {
48 if(pthread_mutex_lock(&sem->mutex) < 0)
50 while(sem->value == 0) {
51 pthread_cond_wait(&sem->cond,&sem->mutex);
54 if(pthread_mutex_unlock(&sem->mutex) < 0)
59 static int sem_destroy(sem_t *sem) {
61 ret = pthread_cond_destroy(&sem->cond);
62 if(ret < 0) return -1;
63 ret = pthread_mutex_destroy(&sem->mutex);
64 if(ret < 0) return -1;