pthread_cleanup_push 问题-转载

#if 0
线程结束时清理函数
pthread_cleanup_push()，应该在线程开始的时候尽快执行初始化
pthread_cleanup_pop()，当遇到以下三种各件会自动调用该函数，不需要PC执行到此函数
1.调用pthread_exit()
2.响应取消请求例如pthread_cancel()
3.当pthread_cleanup_pop(arg)参数arg为非0时会线程退出时自动执行
 
如果没有以上三种情况，则不会执行；
#endif
 
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <semaphore.h>
 
sem_t sm0,sm1,sm2,sm3; //信号量定义 信号量为控制线程的执行
 
void ret_fn(void*str)//线程退出调用的回调函数
{
    fputs(str,stdout);
}
 
 
void thread0(void)
{
    if(0 != sem_wait(&sm0))//信号量进行阻塞
    {
        perror("sem_wait_0");
    }
      
    char *str = "thead0_return_FN is runing\n";
    pthread_cleanup_push(ret_fn,str);//将回调函数入栈
    fputs("thread0 is runing\n",stdout);
    pthread_cleanup_pop(0);//将回调函数出栈，当遇到特定的条件会自动调用，不需要PC指到此才执行
    return;
}
void thread1(void)
{
    if(0 != sem_wait(&sm1))
    {
        perror("sem_wait_1");
    }
    char *str = "thead1_return_FN is runing\n";
    pthread_cleanup_push(ret_fn,str);
    fputs("thread1 is runing\n",stdout);
    pthread_exit((void*)1);
    pthread_cleanup_pop(0);
}
 
void thread2(void)
{
    if(0 != sem_wait(&sm2))
    {
        perror("sem_wait_2");
    }
    char *str = "thead2_return_FN is runing\n";
    pthread_cleanup_push(ret_fn,str);
    fputs("thread2 is runing\n",stdout);
    pthread_cleanup_pop(1);
    fputs("线程结束才会执行pthread_cleanup_pop\n",stdout);//线程结束才会执行pthread_cleanup_pop
}
void thread3(void)
{
    char *str = "thead3_return_FN is runing\n";
    pthread_cleanup_push(ret_fn,str);
    if(0 != sem_wait(&sm3))
    {
        perror("sem_wait_3");
    }
    fputs("thread3 is runing\n",stdout);
    usleep(100);// 让主线程中的pthread_cancel可以执行
    pthread_cleanup_pop(0);
 
}
 
int main(void)
{
 
    pthread_t thd0,thd1,thd2,thd3;
      
    if(0 != sem_init(&sm0,0,0))//初始化信号量
    {
        perror("sem_init_0");
        exit(1);
    }
    if(0 != sem_init(&sm1,0,0))
    {
        perror("sem_init_0");
        exit(1);
    }
    if(0 != sem_init(&sm2,0,0))
    {
        perror("sem_init_0");
        exit(1);
    }
    if(0 != sem_init(&sm3,0,0))
    {
        perror("sem_init_0");
        exit(1);
    }
      
    if(0 != pthread_create(&thd0,NULL,(void*)thread0,NULL))//创建线程
    {
        perror("pthread_create_0\n");
        exit(1);
    }
    if(0 != pthread_create(&thd1,NULL,(void*)thread1,NULL))
    {
        perror("pthread_create_1\n");
        exit(1);
    }
    if(0 != pthread_create(&thd2,NULL,(void*)thread2,NULL))
    {
        perror("pthread_create_2\n");
        exit(1);
    }
    if(0 != pthread_create(&thd3,NULL,(void*)thread3,NULL))
    {
        perror("pthread_create_3\n");
        exit(1);
    }
    unsigned char status = 0xF;//控制重复测试掩码
      
    while(1)
    {
        fputs("请输入测试选项：0(没有调用回调函数),１(pthread_exit),2(pthread_cancel),3(参数非0 pthread_cleanup_pop)\n",stdout);
        int in;
        scanf("%d",&in);
        switch(in)
        {
            case 0:
                {
                    if(!(status & 0x1))
                    {
                        fputs("这个项目已测试过，请选择其它，谢谢\n",stdout);
                        break;
                    }
                    if(0 != sem_post(&sm0))//激活信号量，让子线程THD0继续执行
                    {
                        perror("sem_post_0\n");
                    }
                    status &= 0xe;
                    break;
                }
            case 1:
                {
                    if(!(status & 0x2))
                    {
                        fputs("这个项目已测试过，请选择其它，谢谢\n",stdout);
                        break;
                    }
                    if(0 != sem_post(&sm1))
                    {
                        perror("sem_post_1\n");
                    }
                    status &= 0xc;
                    break;
                }        
            case 2:
                {
                    if(!(status & 0x4))
                    {
                        fputs("这个项目已测试过，请选择其它，谢谢\n",stdout);
                        break;
                    }
                    if(0 != sem_post(&sm2))
                    {
                        perror("sem_post_2\n");
                    }
                    status &= 0xb;
                    break;
                }
            case 3:
                {
                    if(!(status & 0x8))
                    {
                        fputs("这个项目已测试过，请选择其它，谢谢\n",stdout);
                        break;
                    }
                    if(0 != sem_post(&sm3))
                    {
                        perror("sem_post_3\n");
                    }
                    pthread_cancel(thd3);
                    status &= 0x7;
                    break;
                }
            default: break;
        }    
        sleep(1);
    }
 
      
    return 0;
}