6. Practical Signal Handling with signal() Function

pravjot

Describe how the signal() function works in setting up a signal handler in a C program. Provide a brief example of how to use signal() to catch the SIGINT signal (generated by typing Ctrl+C) and handle it with a custom function. What are the possible return values of the signal() function and their significance?

gaurav133232

The signal function has the following prototype : sighandler_t signal(int signum, sighandler_t handler);

here signum is the number of the signal to catch and handler is the function to be called when that signal is catched.

For e.g.:-

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
void handle_signal(int sig)
{
printf("Caught signal %d\n", sig);
}
int main()
{
// Set up the signal handler
signal(SIGINT, handle_signal);
// Loop indefinitely
while (1)
{
printf("Running...\n");
sleep(1);
}
return 0;
}

The signal function returns previous value of the signal handler, or SIG_ERR on error. When an error occurs errno is specified with it which indicates the reason for error.

6. Practical Signal Handling with signal() Function

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