4 pthread_mutex_t a = PTHREAD_MUTEX_INITIALIZER;
5 pthread_mutex_t b = PTHREAD_MUTEX_INITIALIZER;
8 void *ba_lock(void *arg)
12 pthread_mutex_lock(&b);
14 if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD)
15 pthread_barrier_destroy(&bar);
17 pthread_mutex_lock(&a);
19 pthread_mutex_unlock(&a);
20 pthread_mutex_unlock(&b);
27 pthread_barrier_init(&bar, NULL, 2);
29 if (pthread_create(&t, NULL, ba_lock, NULL)) {
30 fprintf(stderr, "pthread_create() failed\n");
33 pthread_mutex_lock(&a);
35 if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD)
36 pthread_barrier_destroy(&bar);
38 pthread_mutex_lock(&b);
40 pthread_mutex_unlock(&b);
41 pthread_mutex_unlock(&a);
43 pthread_join(t, NULL);