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. */
25 # include <stdio_ext.h>
28 #if HAVE_FPURGE && ! HAVE_DECL_FPURGE
34 /* Flush all pending data on STREAM according to POSIX rules. Both
35 output and seekable input streams are supported. */
37 rpl_fflush (FILE *stream)
39 int e; /* Capture errno of first fflush if nothing else succeeds. */
42 /* Try flushing the stream. C89 guarantees behavior of output
43 streams, so we only need to worry if failure might have been on
44 an input stream. When stream is NULL, POSIX only requires
45 flushing of output streams. */
46 result = fflush (stream);
47 if (! stream || result == 0 || (e = errno) != EBADF)
50 /* POSIX does not specify behavior for non-seekable streams. */
51 if (fseeko (stream, 0, SEEK_CUR) != 0)
57 /* To get here, we must be flushing a seekable input stream, so the
58 semantics of fpurge are now appropriate. */
60 result = fpurge (stream);
62 /* __fpurge has no return value, and on Solaris, we can't even trust
63 errno. So assume it succeeds. */
66 #else /* ! HAVE___FPURGE */
68 /* No single replacement; do it manually. */
70 off_t position = ftello (stream);
73 result = EOF; /* Should not happen; we know stream is seekable. */
75 /* Set position of stream; hopefully the stdio routines don't
76 overoptimize by not setting the underlying file position. */
77 else if (fseeko (stream, position, SEEK_SET) != 0)
85 #endif /* ! HAVE___FPURGE */