cosmopolitan/test/posix/signal_test.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set noet ft=c ts=2 sts=2 sw=2 fenc=utf-8                             :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include <signal.h>
#include <stdlib.h>

volatile sig_atomic_t signal_received = 0;

void signal_handler(int signum) {
  // Set the flag to indicate the signal was received
  signal_received = 1;
}

int main() {
  // Install the signal handler
  struct sigaction sa;
  sa.sa_handler = signal_handler;
  sigemptyset(&sa.sa_mask);
  sa.sa_flags = 0;

  if (sigaction(SIGUSR1, &sa, NULL) == -1) {
    // Failed to install signal handler
    exit(1);
  }

  // Raise the signal
  if (raise(SIGUSR1) != 0) {
    // Failed to raise signal
    exit(2);
  }

  // Check if the signal was received
  if (signal_received == 1) {
    // Signal was successfully caught
    exit(0);
  } else {
    // Signal was not caught
    exit(3);
  }
}