1 | /* Waiting for Input or Output |
2 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
3 | |
4 | This program is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU General Public License |
6 | as published by the Free Software Foundation; either version 2 |
7 | of the License, or (at your option) any later version. |
8 | |
9 | This program is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | GNU General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU General Public License |
15 | along with this program; if not, see <https://www.gnu.org/licenses/>. |
16 | */ |
17 | |
18 | /*@group*/ |
19 | #include <errno.h> |
20 | #include <stdio.h> |
21 | #include <unistd.h> |
22 | #include <sys/types.h> |
23 | #include <sys/time.h> |
24 | /*@end group*/ |
25 | |
26 | /*@group*/ |
27 | int |
28 | input_timeout (int filedes, unsigned int seconds) |
29 | { |
30 | fd_set set; |
31 | struct timeval timeout; |
32 | /*@end group*/ |
33 | |
34 | /* Initialize the file descriptor set. */ |
35 | FD_ZERO (&set); |
36 | FD_SET (filedes, &set); |
37 | |
38 | /* Initialize the timeout data structure. */ |
39 | timeout.tv_sec = seconds; |
40 | timeout.tv_usec = 0; |
41 | |
42 | /*@group*/ |
43 | /* @code{select} returns 0 if timeout, 1 if input available, -1 if error. */ |
44 | return TEMP_FAILURE_RETRY (select (FD_SETSIZE, |
45 | &set, NULL, NULL, |
46 | &timeout)); |
47 | } |
48 | /*@end group*/ |
49 | |
50 | /*@group*/ |
51 | int |
52 | main (void) |
53 | { |
54 | fprintf (stderr, "select returned %d.\n" , |
55 | input_timeout (STDIN_FILENO, seconds: 5)); |
56 | return 0; |
57 | } |
58 | /*@end group*/ |
59 | |