103 lines
2.8 KiB
C
103 lines
2.8 KiB
C
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/* Test of POSIX compatible fflush() function.
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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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#include <config.h>
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#include <stdio.h>
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#include "binary-io.h"
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#include "macros.h"
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int
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main (int argc, char **argv)
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{
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int c;
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/* Avoid the well-known bugs of fflush() on streams in O_TEXT mode
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on native Windows platforms. */
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set_binary_mode (0, O_BINARY);
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if (argc > 1)
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switch (argv[1][0])
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{
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case '1':
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/* Check fflush after a backup ungetc() call. This is case 1a in
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terms of
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<https://lists.gnu.org/r/bug-gnulib/2008-03/msg00131.html>,
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according to the Austin Group's resolution on 2009-01-08. */
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c = fgetc (stdin);
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ASSERT (c == '#');
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c = fgetc (stdin);
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ASSERT (c == '!');
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/* Here the file-position indicator must be 2. */
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c = ungetc ('!', stdin);
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ASSERT (c == '!');
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fflush (stdin);
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/* Here the file-position indicator must be 1. */
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c = fgetc (stdin);
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ASSERT (c == '!');
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c = fgetc (stdin);
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ASSERT (c == '/');
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return 0;
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case '2':
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/* Check fflush after a non-backup ungetc() call. This is case 2a in
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terms of
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<https://lists.gnu.org/r/bug-gnulib/2008-03/msg00131.html>,
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according to the Austin Group's resolution on 2009-01-08. */
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/* Check that fflush after a non-backup ungetc() call discards the
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ungetc buffer. This is mandated by POSIX
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<https://pubs.opengroup.org/onlinepubs/9699919799/functions/fflush.html>:
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"...any characters pushed back onto the stream by ungetc()
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or ungetwc() that have not subsequently been read from the
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stream shall be discarded..." */
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c = fgetc (stdin);
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ASSERT (c == '#');
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c = fgetc (stdin);
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ASSERT (c == '!');
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/* Here the file-position indicator must be 2. */
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c = ungetc ('@', stdin);
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ASSERT (c == '@');
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fflush (stdin);
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/* Here the file-position indicator must be 1. */
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c = fgetc (stdin);
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ASSERT (c == '!');
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c = fgetc (stdin);
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ASSERT (c == '/');
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return 0;
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}
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return 1;
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}
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