调用 SIGINT 时终止线程 - C [英] Terminate threads when SIGINT is called - C

问题描述

我正在构建一个用 C-UNIX 编写的通用程序(使用 Linux，所以我不关心 BSD 或 WIN 函数)，它创建了两个线程来处理与服务器的通信.

I'm building a generic program written in C-UNIX (using Linux so I don't care about BSD or WIN functions), that creates two threads to handle the communication with a server.

void init_threads(int socket_desc) {

    pthread_t chat_threads[2];

    ret = pthread_create(&chat_threads[0], NULL, receiveMessage, (void*)(long)socket_desc);
    PTHREAD_ERROR_HELPER(ret, "Errore creazione thread ricezione messaggi");

    ret = pthread_create(&chat_threads[1], NULL, sendMessage, (void*)(long)socket_desc);
    PTHREAD_ERROR_HELPER(ret, "Errore creazione thread invio messaggi");

}

由于这个程序将从 shell 启动，我想实现 CTRL-C 的可能性，所以我用这行代码:

Since this program will be launched from shell I want to implement the CTRL-C possibility and so did I with this line of code:

signal(SIGINT,kill_handler);
// and its related function
void kill_handler() {
        // retrive threads_id
        // call pthread_exit on the two threads
        printf("Exit from program cause ctrl-c, bye bye\n");
        exit(EXIT_SUCCESS);
      }

我的问题是如何找出事件处理函数中的线程 ID，调用 pthread_exit 是否正确还是应该使用其他方法?

My question is how can I found out the thread ids inside the event handler function and is it correct to call pthread_exit or should I use something else?

推荐答案

不要从信号处理程序中调用 pthread_exit()！不需要async-signal-safe，参见信号安全.

Don't call pthread_exit() from a signal handler! It is not required to be async-signal-safe, see signal-safety.

通常，您应该尽可能少在信号处理程序中执行操作.常见的习惯用法是设置一个在主循环中定期检查的标志，例如

In general, you should do as little as possible in a signal handler. The common idiom is to just set a flag that is periodically checked in your main loop like e.g.

volatile sig_atomic_t exitRequested = 0;

void signal_handler(int signum)
{
    exitRequested = 1;
}

int main(void)
{
    // init and setup signals

    while (!exitRequested)
    {
        // do work
    }

    // cleanup
}

另外，使用 sigaction() 用于安装信号处理程序.请参阅 signal() 了解不使用它的原因.

Also, use sigaction() for installing signal handlers. See signal() for reasons not to use it.

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