1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
/* Test of select() substitute, reading or writing from a given file descriptor.
Copyright (C) 2008-2018 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2008. */
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/select.h>
int
main (int argc, char *argv[])
{
if (argc == 4)
{
char mode = argv[1][0];
if (mode == 'r' || mode == 'w')
{
int fd = atoi (argv[2]);
if (fd >= 0)
{
const char *result_file_name = argv[3];
FILE *result_file = fopen (result_file_name, "wb");
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);
}
}
}
}
fprintf (stderr, "Usage: test-select-fd mode fd result-file-name\n");
exit (1);
}
|
