Simple timeout implementation using SIGALRM

timeout.c

//
//  main.c
//  timeout
//
//  Created by Paolo Bosetti on 04/06/14.
//  Copyright (c) 2014 UniTN. All rights reserved.
//

#include <stdio.h>
#include <signal.h>
#include <unistd.h>


void signal_handler(int sig);
void start_timer(useconds_t useconds);

int  timeout_flag = 0;

int main(int argc, const char * argv[]) {
  printf("Start...\n");
  start_timer(1e6);
  int i;
  for (i=0; i<1e6; i++) {
    if (timeout_flag == 1)
      break;
    usleep(10);
  }
  printf("end working (i=%d)\n", i);
}


void start_timer(useconds_t useconds)
{
  struct sigaction sigact;
  sigact.sa_handler = signal_handler;
  sigact.sa_flags   = SA_RESETHAND;
  sigemptyset(&sigact.sa_mask);
  sigaction(SIGALRM, &sigact, NULL);
  ualarm(useconds, 0);
}


void signal_handler(int sig)
{
  if (sig == SIGALRM) {
    timeout_flag = 1;
    printf("Timeout!\n");
  }
}