manual/examples/select.c

   1 /*@group*/
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <sys/types.h>
   5 #include <sys/time.h>
   6 /*@end group*/
   7
   8 /*@group*/
   9 int
  10 input_timeout (int filedes, unsigned int seconds)
  11 {
  12   fd_set set;
  13   struct timeval timeout;
  14 /*@end group*/
  15
  16   /* Initialize the file descriptor set. */
  17   FD_ZERO (&set);
  18   FD_SET (filedes, &set);
  19
  20   /* Initialize the timeout data structure. */
  21   timeout.tv_sec = seconds;
  22   timeout.tv_usec = 0;
  23
  24 /*@group*/
  25   /* @code{select} returns 0 if timeout, 1 if input available, -1 if error. */
  26   return TEMP_FAILURE_RETRY (select (FD_SETSIZE,
  27                                      &set, NULL, NULL,
  28                                      &timeout));
  29 }
  30 /*@end group*/
  31
  32 /*@group*/
  33 int
  34 main (void)
  35 {
  36   fprintf (stderr, "select returned %d.\n",
  37            input_timeout (STDIN_FILENO, 5));
  38   return 0;
  39 }
  40 /*@end group*/