A snippet for testing libev signal watcher behavior across fork and loop destruction.

libev_signal_watcher_test.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <signal.h>
#include <ev.h>


void sigtermhandler(struct ev_loop *l, ev_signal *w, int revents) {
    printf("SIGTERM handler called in process %d\n", getpid());
    ev_break(l, EVBREAK_ALL);
}


void child(struct ev_loop *loop) {
    printf("Msg from child with PID %d\n", getpid());
    ev_loop_destroy(loop);

    // Reset signal handler:
    //signal(SIGTERM, SIG_DFL);

    struct ev_loop *newloop = ev_default_loop(0);
    ev_run(newloop, 0);
}


int main (void) {
    printf("Msg from parent with PID %d\n", getpid());
    struct ev_loop *loop = EV_DEFAULT;

    // Install signal watcher in parent, handling SIGTERM.
    ev_signal signal_watcher;
    ev_signal_init(&signal_watcher, sigtermhandler, SIGTERM);
    ev_signal_start(loop, &signal_watcher);

    pid_t  pid;
    pid = fork();
    if (pid == -1) {
        fprintf(stderr, "Can't fork, error %d\n", errno);
        exit(1);
    }
    else if (pid == 0) {
        child(loop);
        exit(0);
    }
    // Dirtywait until child is upnrunning, then send SIGTER.
    sleep(1);
    kill(pid, SIGTERM);
    //ev_run (loop, 0);
    printf("Waiting for child.\n");
    wait();
    printf("Child finished, exit parent.\n");
}