C program that does not suspend when Ctrl+Z is pressed

Write a C program that doesn’t terminate when Ctrl+Z is pressed. It prints a message “Cannot be suspended using Ctrl+Z” and continues execution.

We can use Unix signal for this. When Ctrl+Z is pressed, SIGTSTP signal is generated.

SIGTSTP signal is sent to a process by its controlling terminal to request it to stop (terminal stop). We can catch this signal and run our own defined signal.
The standard C library function signal() can be used to set up a handler for any of the above signals.

// C program that does not suspend when 
// Ctrl+Z is pressed 
#include <stdio.h> 
#include <signal.h> 
  
// Signal Handler for SIGTSTP 
void sighandler(int sig_num) 
{ 
    // Reset handler to catch SIGTSTP next time 
    signal(SIGTSTP, sighandler); 
    printf("Cannot execute Ctrl+Z\n"); 
} 
  
int main() 
{ 
    // Set the SIGTSTP (Ctrl-Z) signal handler 
    // to sigHandler 
    signal(SIGTSTP, sighandler); 
    while(1) 
    { 
    } 
    return 0; 
} 

Output:

Cannot execute Ctrl+Z

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