Question

Write any C code to:

- Overwrite a signal handler to use a provided function

Please explain the steps

Answer 1

Program:

/* A C program that does not terminate when Ctrl+C is pressed */

#include <stdio.h>

#include <signal.h>

  

/* Signal Handler for SIGINT */

void sigintHandler(int sig_num)

{

    // Reset handler to catch SIGINT next time.

    signal(SIGINT, sigintHandler);

    printf("\n Cannot be terminated using Ctrl+C \n");

    fflush(stdout);

}

  

int main ()

{

    // Set the SIGINT (Ctrl-C) signal handler to sigintHandler

    signal(SIGINT, sigintHandler);

  

    /* Infinite loop */

    while(1)

    {        

    }

    return 0;

}

Output: When Ctrl+C was pressed two times

 
 Cannot be terminated using Ctrl+C
 
 Cannot be terminated using Ctrl+C

Note: Press Ctrl+Z to exit the process or else it will run in infinite loop.