1 /* Test of select() substitute, reading from stdin.
2 Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
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.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Bruno Haible <bruno@clisp.org>, 2008. */
23 #include <sys/select.h>
30 printf ("Applying select() from standard input. Press Ctrl-C to abort.\n");
33 struct timeval before;
35 unsigned long spent_usec;
37 struct timeval timeout;
40 gettimeofday (&before, NULL);
45 timeout.tv_usec = 500000;
46 ret = select (1, &readfds, NULL, NULL, &timeout);
48 gettimeofday (&after, NULL);
49 spent_usec = (after.tv_sec - before.tv_sec) * 1000000
50 + after.tv_usec - before.tv_usec;
54 perror ("select failed");
57 if ((ret == 0) != ! FD_ISSET (0, &readfds))
59 fprintf (stderr, "incorrect return value\n");
64 if (spent_usec < 250000)
66 fprintf (stderr, "returned too early\n");
70 printf ("."); fflush (stdout);
76 printf ("Input available! Trying to read 1 byte...\n");