多线程，线程的退出顺序

Posted 2020-09-03 邶风

 

 1：主进程退出时，不管子、孙...线程都会退出。但是对子线程创建的线程来说，比如下面的的子线程创建了孙线程，子线程先退出，孙线程没有退出

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

void* fun(void* v)
{
    sleep(10);
    printf("grandson thread exit\n");
}


void* thrd_start_routine(void* v)
{
    pthread_t thd;
    pthread_create(&thd, NULL, &fun, NULL);
    sleep(5);
    printf("created thread exit\n");
}

int main()
{
        pthread_t thrdid;
                
        pthread_create(&thrdid, NULL, &thrd_start_routine, NULL);
        
        sleep(15);
        printf("main thread exit\n");
        return  0;
}

输出是
//过了5秒
created thread exit
//又过了5秒
grandson thread exit
//又过了5秒
main thread exit

2：如果主线程调用了pthread_exit，那么它退出了，子线程也不会退出

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

void* thrd_start_routine(void* v)
{
    　sleep(10);
        printf("created thread\n");
}

int main()
{
        pthread_t thrdid;
                
        pthread_create(&thrdid, NULL, &thrd_start_routine, NULL);
        
        sleep(5);
        printf("main thread\n");
        pthread_exit(NULL);
        return  0;
}

//过了5秒
main thread
//又过了5秒
created thread