#include <pthread.h>
int global_value=0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
void *thr_fn1(void *arg)
{
pthread_mutex_lock(&mutex);
global_value=555;
pthread_mutex_unlock(&mutex);
return((void *)1);
}
void *thr_fn2(void *arg)
{
pthread_mutex_lock(&mutex);
if(global_value==555) { printf("5555555555\n"); }
pthread_mutex_unlock(&mutex);
pthread_exit((void *)1);
}
int main(void)
{
int err;
pthread_t tid1, tid2;
void *tret;
err = pthread_create(&tid1, NULL, thr_fn1, NULL);
err = pthread_create(&tid2, NULL, thr_fn2, NULL);
err = pthread_join(tid1, NULL);
err = pthread_join(tid2, NULL);
//当对线程的返回值不感兴趣时,置为NULL
exit(0);
}