自定义 SIGINT 信号处理程序 - 即使在捕获到信号后程序仍然终止

Question

我正在使用 signal.h 和 unistd.h 库，但遇到了一些问题。在下面的代码中，当我通过调用 CTRL-C 向正在运行的程序发送 SIGINT 信号时，该信号被捕获。然而，当再次按下 CTRL-C 时，程序终止。据我了解，每次我按下 CTRL-C 时，打印语句 "Received signal 2" 都应该被打印出来。

是我对这个信号的理解不正确，还是我的代码有错误？

感谢您的意见!

#include "handle_signals.h"


void sig_handler(int signum)
{
    printf("\nReceived signal %d\n", signum);
}

int main()
{
    signal(SIGINT, sig_handler);
    while(1)
    {
        sleep(1);
    }
    return 0;
}

终端输出:

xxx@ubuntu:~/Dropbox/xxx/handle_signals$ ./handle_signals 
^C
Received signal 2
^C
xxx@ubuntu:~/Dropbox/xxx/handle_signals$ 

编辑:这是我包含的标题

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>


void sig_handler(int signum);

感谢您的回复。现在通读它们!

Answer 1

不要使用signal，使用sigaction:

The behavior of signal() varies across UNIX versions, and has also varied historically across different versions of Linux. Avoid its use: use sigaction(2) instead.

http://man7.org/linux/man-pages/man2/signal.2.html

In the original UNIX systems, when a handler that was established using signal() was invoked by the delivery of a signal, the disposition of the signal would be reset to SIG_DFL, and the system did not block delivery of further instances of the signal.

Linux 实现了相同的语义:当信号被传递时处理程序被重置。