- FD_ZERO (&fds);
- FD_SET (fd, &fds);
- timeout.tv_sec = 0;
- timeout.tv_usec = 10000;
- ret = (mode == 'r'
- ? select (fd + 1, &fds, NULL, NULL, &timeout)
- : select (fd + 1, NULL, &fds, NULL, &timeout));
- if (ret < 0)
- {
- perror ("select failed");
- exit (1);
- }
- if ((ret == 0) != ! FD_ISSET (fd, &fds))
- {
- fprintf (stderr, "incorrect return value\n");
- exit (1);
- }
- fprintf (stderr, "%d\n", ret);
- exit (0);
- }
- }
+ if (result_file != NULL)
+ {
+ fd_set fds;
+ struct timeval timeout;
+ int ret;
+
+ FD_ZERO (&fds);
+ FD_SET (fd, &fds);
+ timeout.tv_sec = 0;
+ timeout.tv_usec = 10000;
+ ret = (mode == 'r'
+ ? select (fd + 1, &fds, NULL, NULL, &timeout)
+ : select (fd + 1, NULL, &fds, NULL, &timeout));
+ if (ret < 0)
+ {
+ perror ("select failed");
+ exit (1);
+ }
+ if ((ret == 0) != ! FD_ISSET (fd, &fds))
+ {
+ fprintf (stderr, "incorrect return value\n");
+ exit (1);
+ }
+ fprintf (result_file, "%d\n", ret);
+ exit (0);
+ }
+ }
+ }