Handling SIGINT (Ctrl+c From Keyboard) in C

If you have developed a shell for your own command line program in python; you are likely to have used something like following code.

    # your stuff..
except KeyboardInterrupt:

The above code is used to ignore the KeyboardInterrupt ie. when you press Ctrl+c from the keyboard. python makes it really easy for you.

If you want to do the same thing in c you need to handle what in nix world called as singnals. Here is a good description of what signals are, it is taken from yolinux

Signals are software interrupts delivered to a process by the operating system.
Signals can also be issued by the operating system based on system or error

What happens when you press Ctrl+c from the keyboard is the os delivers a Interrupt signal to the process that is running in your bash or whatever shell you are currently running. While developing a shell you need to ignore this interrupt. If you happen to be developing this shell in c, you will have to do the following things in order to handle SIGINT.

Following is the demo for that.

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

// The callback function.
exit_func(int signal_number)
    if (signal_number == 2)
        printf("Ctrl+c Pressed, exitting...\n");

int main()
    // register the callback function for signal from os.
    signal(SIGINT, exit_func);

    // do your stuff here
    // ...
    while (1)

    return EXIT_SUCCESS;