thread_cancel

hyh@hyh-OptiPlex-9020:~/git/hyh_home/1512_home/应用程序设计/多线程$ cat th.c
#include <pthread.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>

#define handle_error_en(en, msg) \
    do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)

static void *
thread_func(void *ignored_argument)
{
    int s;

    /* Disable cancellation for a while, so that we don't
       immediately react to a cancellation request */

    s = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
    if (s != 0)
        handle_error_en(s, "pthread_setcancelstate");

    printf("thread_func(): started; cancellation disabled\n");
    sleep(5);
    printf("thread_func(): about to enable cancellation\n");

    s = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
    if (s != 0)
        handle_error_en(s, "pthread_setcancelstate");

    /* sleep() is a cancellation point */

    sleep(1000);        /* Should get canceled while we sleep */

    /* Should never get here */

    printf("thread_func(): not canceled!\n");
    return NULL;
}

int
main(void)
{
    pthread_t thr;
    void *res;
    int s;

    /* Start a thread and then send it a cancellation request */

    s = pthread_create(&thr, NULL, &thread_func, NULL);
    if (s != 0)
        handle_error_en(s, "pthread_create");

    sleep(2);           /* Give thread a chance to get started */

    printf("main(): sending cancellation request: thr:%d\n",thr);
    s = pthread_cancel(thr);
    if (s != 0)
        handle_error_en(s, "pthread_cancel");

    /* Join with thread to see what its exit status was */
    printf("pthread_cancel call\n");
    s = pthread_join(thr, &res); //等待thr 被取消
    if (s != 0)
        handle_error_en(s, "pthread_join");

    if (res == PTHREAD_CANCELED)
        printf("main(): thread was canceled\n");
    else
        printf("main(): thread wasn't canceled (shouldn't happen!)\n");
    exit(EXIT_SUCCESS);
}

hyh@hyh-OptiPlex-9020:~/git/hyh_home/1512_home/应用程序设计/多线程$ ./a.out
thread_func(): started; cancellation disabled   知道状态变为able,会被取消。
main(): sending cancellation request: thr:-1309870336
pthread_cancel call   main:线程运行到这里，等待子线程退出.
thread_func(): about to enable cancellation
main(): thread was canceled
hyh@hyh-OptiPlex-9020:~/git/hyh_home/1512_home/应用程序设计/多线程$