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/* Test of select() substitute, reading from stdin.
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Copyright (C) 2008-2019 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>, 2008. */
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/select.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include "macros.h"
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int
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main (void)
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{
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printf ("Applying select() from standard input. Press Ctrl-C to abort.\n");
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for (;;)
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{
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struct timeval before;
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struct timeval after;
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unsigned long spent_usec;
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fd_set readfds;
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struct timeval timeout;
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int ret;
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gettimeofday (&before, NULL);
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FD_ZERO (&readfds);
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FD_SET (0, &readfds);
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timeout.tv_sec = 0;
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timeout.tv_usec = 500000;
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ret = select (1, &readfds, NULL, NULL, &timeout);
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gettimeofday (&after, NULL);
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spent_usec = (after.tv_sec - before.tv_sec) * 1000000
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+ after.tv_usec - before.tv_usec;
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if (ret < 0)
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{
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perror ("select failed");
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exit (1);
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}
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if ((ret == 0) != ! FD_ISSET (0, &readfds))
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{
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fprintf (stderr, "incorrect return value\n");
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exit (1);
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}
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if (ret == 0)
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{
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if (spent_usec < 250000)
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{
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fprintf (stderr, "returned too early\n");
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exit (1);
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}
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/* Timeout */
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printf (".");
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ASSERT (fflush (stdout) == 0);
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}
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else
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{
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char c;
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printf ("Input available! Trying to read 1 byte...\n");
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ASSERT (read (0, &c, 1) == 1);
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}
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}
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}
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