#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include "time.h" 		/* gnulib time.h */
#include <setjmp.h>

#define TIME_CHECK_GOOD -67768038400760896
#define TIME_CHECK_BAD -67768038400750896

static jmp_buf buf;
static time_t check_time = TIME_CHECK_GOOD;
static time_t last_good_time = TIME_CHECK_GOOD;
static time_t last_bad_time = TIME_CHECK_BAD;

/* time_find.c */

int localtime_hang_handler () {
  printf ("Hang detected for %ld\n", (long) check_time);
  last_bad_time = check_time;
  check_time = last_good_time;
  longjmp(buf, 1);
}

int main () {
  struct tm output_time;
  signal (SIGALRM, (void *) localtime_hang_handler);

  if(setjmp(buf))
  next:
    check_time = (check_time + last_bad_time) / 2;
  alarm(1);

  localtime_r (&check_time, &output_time);
  printf ("No hang for       %ld\n", (long) check_time);
  alarm(0);
  last_good_time = check_time;

  goto next;
  return 0;
}