1 /* All OK */ 2 3 #include <pthread.h> 4 5 static pthread_mutex_t mx = PTHREAD_MUTEX_INITIALIZER; 6 7 static int shared; 8 th(void * v)9static void *th(void *v) 10 { 11 pthread_mutex_lock(&mx); 12 shared++; 13 pthread_mutex_unlock(&mx); 14 15 return 0; 16 } 17 main()18int main() 19 { 20 pthread_t a, b; 21 22 pthread_mutex_lock(&mx); 23 pthread_mutex_unlock(&mx); 24 25 pthread_create(&a, NULL, th, NULL); 26 pthread_create(&b, NULL, th, NULL); 27 28 pthread_join(a, NULL); 29 pthread_join(b, NULL); 30 31 return 0; 32 } 33