73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
/* Test of select() substitute, reading or writing from a given file descriptor.
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Copyright (C) 2008-2021 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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int
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main (int argc, char *argv[])
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{
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if (argc == 4)
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{
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char mode = argv[1][0];
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if (mode == 'r' || mode == 'w')
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{
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int fd = atoi (argv[2]);
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if (fd >= 0)
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{
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const char *result_file_name = argv[3];
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FILE *result_file = fopen (result_file_name, "wb");
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if (result_file != NULL)
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{
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fd_set fds;
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struct timeval timeout;
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int ret;
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FD_ZERO (&fds);
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FD_SET (fd, &fds);
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timeout.tv_sec = 0;
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timeout.tv_usec = 10000;
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ret = (mode == 'r'
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? select (fd + 1, &fds, NULL, NULL, &timeout)
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: select (fd + 1, NULL, &fds, NULL, &timeout));
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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 (fd, &fds))
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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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fprintf (result_file, "%d\n", ret);
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exit (0);
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}
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}
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}
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}
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fprintf (stderr, "Usage: test-select-fd mode fd result-file-name\n");
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exit (1);
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}
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