1 /* fflush.c -- allow flushing input streams
2 Copyright (C) 2007 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 2, or (at your option)
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, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18 /* Written by Eric Blake. */
28 /* Flush all pending data on STREAM according to POSIX rules. Both
29 output and seekable input streams are supported. */
31 rpl_fflush (FILE *stream)
36 /* Try flushing the stream. C89 guarantees behavior of output
37 streams, so we only need to worry if failure might have been on
38 an input stream. When stream is NULL, POSIX only requires
39 flushing of output streams. */
40 result = fflush (stream);
41 if (! stream || result == 0 || errno != EBADF)
44 /* POSIX does not specify fflush behavior for non-seekable input
46 pos = ftello (stream);
53 /* To get here, we must be flushing a seekable input stream, so the
54 semantics of fpurge are now appropriate to clear the buffer. To
55 avoid losing data, the lseek is also necessary. */
56 result = fpurge (stream);
57 if (result == 0 && lseek (fileno (stream), pos, SEEK_SET) == -1)