How to properly handle signals in C

Question

I have really really simple program in C, let me cope paste it from internet there:

#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
void sigint_handler(int dummy)
{
    printf("SIGINT HANDLED!\n");
    signal(SIGINT,sigint_handler);
}

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

    kill(getpid(),SIGINT);
    sleep(1);

    return 0;
}

My question is, what does this line do ?

signal(SIGINT,sigint_handler);

Is it even necessary? Without this line this program works just fine and nothing changes.

Did you read "man signal"? – freestyle Nov 24 '16 at 23:20 — freestyle, Nov 24 '16 at 23:20

score 0 · Answer 1 · answered Nov 25 '16 at 00:59

0

signal(SIGINT,sigint_handler); tells the computer to call sigint_handler the next time your program receives SIGINT.

answered Nov 25 '16 at 00:59

user253751

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Sadly I think u misunderstood me. I was thinking about line in signal handler. I know that this command is necessary in function int main, but what about this command in sigint_handler itself? – ogarogar Nov 25 '16 at 08:55
@ogarogar It does exactly what I said. It tells the computer to call `sigint_handler` the *next* time your program receives SIGINT. – user253751 Nov 26 '16 at 01:08

How to properly handle signals in C

1 Answers1