条件变量使用

#include 
pthread_cond_t              wakeup_cond;
pthread_mutex_t             tlock;
pthread_t                   tid1;
pthread_t                   tid2;

int a = 100;
static void *smr_thread_handler(void *arg){
        printf("my name is :pthread_self():%d\n",pthread_self());
        while(1){
                pthread_mutex_lock(&tlock);
                if(a != 200){
                        printf("thread wait:%d\n",pthread_self());
                        pthread_cond_wait(&wakeup_cond, &tlock);
                        printf("thread exit:%d\n",pthread_self());
                        pthread_mutex_unlock(&tlock);
                        pthread_exit(NULL);
                }
                pthread_mutex_unlock(&tlock);

        }
}

int main(){
        int i = 0;
        int ret;
        pthread_cond_init(&wakeup_cond, NULL);
        pthread_mutex_init(&tlock, NULL);


        ret = pthread_create(&tid1, NULL,&smr_thread_handler,NULL);
        if (0 != ret) {
                printf("pthread_create 1 success\n");
                return -1;
        }

        ret = pthread_create(&tid2, NULL,&smr_thread_handler,NULL);
        if (0 != ret) {
                printf("pthread_create 2 success\n");
                return -1;
        }

        while(1){
                if(i++ == 10){
                        a = 200;
                        printf("main set broad caset\n");
                        pthread_cond_broadcast(&wakeup_cond);
                }
                printf("main wait\n");
            sleep(1);
        }
}