取消 pthread 似乎很奇怪

Question

我有一个简单的测试，在将此函数分配为工作函数时取消 pthread：

static void * thread_start(void *arg)
{
    printf("New thread started\n");
    pthread_cleanup_push(cleanup_handler, NULL);
    pthread_cancel(pthread_self());
    pthread_testcancel();           /* A cancellation point */
    return NULL;
}

cleanup_handler:

static void cleanup_handler(void *arg)
{
    printf("Called clean-up handler\n");
}

但是我得到一些无关语法错误的编译器错误（在其他地方缺少'}'）。另一方面，如果我像这样添加 pthread_cleanup_pop(1)：

static void * thread_start(void *arg)
{
    printf("New thread started\n");
    pthread_cleanup_push(cleanup_handler, NULL);
    pthread_cancel(pthread_self());
    pthread_testcancel();           /* A cancellation point */
    pthread_cleanup_pop(1);  //added this
    return NULL;
}

它按预期进行编译和运行（pthread_cleanup_pop(1) 不是运行）。 cleanup_handler 被执行并且线程 returns PTHREAD_CANCLED.

最后有 pthread_cleanup_pop(1) 是完全不相关的，因为当线程即将终止时，所有清理处理程序都应该总是运行。如果没有我取消，我什至不在乎它们是否运行。

怎么了？

已解决

Answer 1

正在查看the man

POSIX.1 permits pthread_cleanup_push() and pthread_cleanup_pop() to be implemented as macros that expand to text containing '{' and '}', respectively. For this reason, the caller must ensure that calls to these functions are paired within the same function, and at the same lexical nesting level. (In other words, a clean-up handler is established only during the execution of a specified section of code.)

^强调我的

取消 pthread 似乎很奇怪

Cancellation of pthread seems weird

c

multithreading

posix

pthreads

pthread-cleanup

已解决