test/test-unsigaction.c

#include <signal.h>          /* sigemptyset(), sigaction(), kill(), SIGUSR1 */
#include <stdlib.h>                                               /* exit() */
#include <unistd.h>                                             /* getpid() */
#include <errno.h>                                                 /* errno */
#include <stdio.h>                                             /* fprintf() */

static void mysig_handler(int sig) {

  exit(2);

}

int main() {

  /* setup sig handler */
  struct sigaction sa;
  sa.sa_handler = mysig_handler;
  sigemptyset(&sa.sa_mask);
  sa.sa_flags = 0;
  if (sigaction(SIGCHLD, &sa, NULL)) {

    fprintf(stderr, "could not set signal handler %d, aborted\n", errno);
    exit(1);

  }

  kill(getpid(), SIGCHLD);
  return 0;

}