Signals¶

signal(SIGINT, handle_sigint);

What does this line do?¶

• SIGINT:

• SIGINT (Signal Interrupt) is a signal sent to a process when the user presses Ctrl+C in the terminal.

• By default, this signal terminates the process.

• signal(SIGINT, handle_sigint);:

• This registers a custom signal handler function, handle_sigint, to be executed when the SIGINT signal is received.
• Instead of terminating the process immediately, the program will call handle_sigint() when Ctrl+C is pressed.

Example Usage:

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

void handle_sigint(int sig) {
    printf("\nCaught signal %d (SIGINT). Ignoring Ctrl+C.\n", sig);
}

int main() {
    signal(SIGINT, handle_sigint);

    while (1) {
        printf("Running... Press Ctrl+C to test signal handling.\n");
        sleep(2);
    }

    return 0;
}

• The handle_sigint function is called when Ctrl+C is pressed.
• Instead of terminating the program, it prints a message.
• The while (1) loop keeps the program running.

[!TIP] If better signal handling (like resetting behavior after handling) is required, use sigaction() instead of signal(), as signal() behavior can be inconsistent across systems.