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*/
27int
28input_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*/
51int
52main (void)
53{
54 fprintf (stderr, "select returned %d.\n",
55 input_timeout (STDIN_FILENO, seconds: 5));
56 return 0;
57}
58/*@end group*/
59

source code of glibc/manual/examples/select.c