pthread_cancel()取消线程

代码下载a.zip

#include<pthread.h>
int pthread_cancel(pthread_t tid)

线程取消属性没有包含在pthread_attr_t结构中，所以调用pthread_cancel(pthread_t tid)不需要初始化pthread_attr_t结构；

#include<pthread.h>
int pthread_setcanceltypeint type,int *oldtype)

当设置type为PTHREAD_CANCEL_ASYNCHRONOUS异步取消时，线程可以在不遇到取消点时就可以取消，就是说一被cancel就停止运行
若type设置为PTHREAD_CANCEL_DEFERRED延迟取消时，线程必须要等到取消点才能取消。

关于pthread_setcancelstate就不多说了，在书上331页有讲解。
一个取消的例子

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

pthread_t tid1,tid2;

void *fn_1(void *arg)
{
    pthread_setcancelstate(PTHREAD_CANCEL_ENABLE,NULL);
    printf("Thread 1 is running...\n");
    while(1)
    {
        printf("running...\n");
        sleep(1);
    }
    printf("I was cancelled by other thread\n");
    pthread_exit((void*)1);
}

void *fn_2(void*arg)
{
    printf("Thread 2 is running...I will cancel thread 1 after 5 seconds\n");
    sleep(5);
    pthread_cancel(tid1);
    pthread_exit((void*)2);
}

int main()
{
    pthread_create(&tid1,NULL,fn_1,NULL);
    pthread_create(&tid2,NULL,fn_2,NULL);
    pthread_join(tid1,NULL);
    pthread_join(tid2,NULL);
    return 0;
}

运行结果：

[vibe@localhost code]$ ./a
Thread 1 is running...
running...
Thread 2 is running...I will cancel thread 1 after 5 seconds
running...
running...
running...
running...