CODEWITHSUNDEEP
objective-ccocoa
frdmn
frdmn

Reputation: 369

Execute function before application gets quit

I'd like to call a function before processing the stop/kill signal.

Is there an easy way to do this?

Upvotes: 1

Views: 299

Answers (1)

trojanfoe
trojanfoe

Reputation: 122381

You can handle a SIGTERM and SIGINT signal by setting-up a signal handler (see signal(3)), however you cannot handle SIGKILL, which is why it should be the last resort to use against a program.

If you always want to do something before the process exits, then see atexit(3).

$ cat sig.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>

static void closedown() {
    printf("running closedown\n");
}

static void sighandler(int signal) {
    exit(1);
}

int main(int argc, const char **argv) {
    signal(SIGTERM, sighandler);
    signal(SIGINT, sighandler);
    atexit(closedown);
    while (1) {
        sleep(1);
        printf("tick\n");
    }
    return 0;
}

$ clang -o sig sig.c
$ ./sig
tick
tick
^Crunning closedown

Upvotes: 5

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