pthreads - pthread : one printf statement get printed twice in child thread

这是我的第一个pthread程序，我不知道为什么在子线程中将printf语句打印两次:

int x = 1;

void *func(void *p)
{
    x = x + 1;
    printf("tid %ld: x is %d\n", pthread_self(), x);
    return NULL;
}

int main(void)
{
    pthread_t tid;
    pthread_create(&tid, NULL, func, NULL);

    printf("main thread: %ld\n", pthread_self());

    func(NULL);
}

在我的平台(Linux 3.2.0-32-通用＃51-Ubuntu SMP x86_64 GNU/Linux)上观察到的输出:

1.
main thread: 140144423188224
tid 140144423188224: x is 2

2.
main thread: 140144423188224
tid 140144423188224: x is 3

3.
main thread: 139716926285568
tid 139716926285568: x is 2
tid 139716918028032: x is 3
tid 139716918028032: x is 3

4.
main thread: 139923881056000
tid 139923881056000: x is 3
tid 139923872798464tid 139923872798464: x is 2

对于3，子线程有两条输出线

4，与3相同，甚至输出是交错的。

最佳答案

似乎真正的答案是Michael Burr的评论，其中引用了此glibc错误:https://sourceware.org/bugzilla/show_bug.cgi?id=14697

总而言之，glibc在程序退出期间无法正确处理stdio缓冲区。

关于pthreads - pthread : one printf statement get printed twice in child thread，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13550662/