How Can `sigaction` Be Used to Handle Ctrl-C Events in C ?

Using sigaction to Handle Ctrl-C Events in C

To efficiently catch a Ctrl-C event in C , the most reliable approach is to utilize the 'sigaction' function. It provides greater control and compatibility than the simple 'signal' function.

Implementing sigaction requires a structured approach:

1. Declare a sigaction Structure:
   Define a 'sigaction' structure named 'sigIntHandler'.
2. Set the Signal Handler:
   Assign the address of the handler function ('my_handler') to 'sigIntHandler.sa_handler'. In the handler function, perform the desired actions upon receiving the signal.
3. Initialize Signal Mask:
   Initialize 'sigIntHandler.sa_mask' to an empty signal set using 'sigemptyset'. This allows the handler to respond to the specified signal without blocking others.
4. Set Signal Action Flags:
   Set 'sigIntHandler.sa_flags' to '0' to use the default options.
5. Register Signal Action:
   Use 'sigaction' with the 'SIGINT' signal and the defined handler structure ('sigIntHandler') to register the signal action.
6. Pause Execution:
   Call 'pause()' to halt the program execution until a signal is received.
7. Example Code:
   The following modified code from the question demonstrates the use of 'sigaction':

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

void my_handler(int s){
    printf("Caught signal %d\n",s);
    exit(1);
}

int main(int argc,char** argv)
{
    struct sigaction sigIntHandler;
    
    sigIntHandler.sa_handler = my_handler;
    sigemptyset(&sigIntHandler.sa_mask);
    sigIntHandler.sa_flags = 0;
    
    sigaction(SIGINT, &sigIntHandler, NULL);
    pause();
    
    return 0;    
}

This approach provides a robust mechanism for handling Ctrl-C events in C , ensuring reliability and efficiency in various implementations.

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