manual/examples/sigh1.c

   1 #include <signal.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4
   5 /* This flag controls termination of the main loop. */
   6 volatile sig_atomic_t keep_going = 1;
   7
   8 /* The signal handler just clears the flag and re-enables itself. */
   9 void
  10 catch_alarm (int sig)
  11 {
  12   keep_going = 0;
  13   signal (sig, catch_alarm);
  14 }
  15
  16 void
  17 do_stuff (void)
  18 {
  19   puts ("Doing stuff while waiting for alarm....");
  20 }
  21
  22 int
  23 main (void)
  24 {
  25   /* Establish a handler for SIGALRM signals. */
  26   signal (SIGALRM, catch_alarm);
  27
  28   /* Set an alarm to go off in a little while. */
  29   alarm (2);
  30
  31   /* Check the flag once in a while to see when to quit. */
  32   while (keep_going)
  33     do_stuff ();
  34
  35   return EXIT_SUCCESS;
  36 }