cond.c

基于linux的系统编程程序

#include <stdio.h>
#include <pthread.h>
#include <unistd.h>

pthread_mutex_t mutex;
pthread_cond_t  cond;

void  child1(void)
{
        pthread_cleanup_push(pthread_mutex_unlock,&mutex);  /* comment 1 */
        while(1){
                printf("thread 1 get running \n");
        printf("thread 1 pthread_mutex_lock returns %d\n",
pthread_mutex_lock(&mutex));
        pthread_cond_wait(&cond,&mutex);
                    printf("thread 1 condition applied\n");
        pthread_mutex_unlock(&mutex);
                    sleep(5);
    }
        pthread_cleanup_pop(0);     /* comment 2 */
}

void child2(void)
{
        while(1){
                sleep(3);               /* comment 3 */
                printf("thread 2 get running.\n");
        printf("thread 2 pthread_mutex_lock returns %d\n",
pthread_mutex_lock(&mutex));
        pthread_cond_wait(&cond,&mutex);
        printf("thread 2 condition applied\n");
        pthread_mutex_unlock(&mutex);
        sleep(1);
        }
}

int main(void)
{
        int tid1,tid2;

        printf("hello, condition variable test\n");
        pthread_mutex_init(&mutex,NULL);
        pthread_cond_init(&cond,NULL);
        pthread_create(&tid1,NULL,(void *)child1,NULL);
        pthread_create(&tid2,NULL,(void *)child2,NULL);
        do{
        sleep(2);                   /* comment 4 */
                pthread_cancel(tid1);       /* comment 5 */
                sleep(2);                   /* comment 6 */
        pthread_cond_signal(&cond);
    }while(1);  
        sleep(100);
        pthread_exit(0);
}