1 /* Flushing buffers of a FILE stream.
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 along
15 with this program; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
23 #if HAVE___FPURGE /* glibc >= 2.2, Solaris >= 7 */
24 # include <stdio_ext.h>
31 #if HAVE___FPURGE /* glibc >= 2.2, Solaris >= 7 */
34 /* The __fpurge function does not have a return value. */
37 #elif HAVE_FPURGE /* FreeBSD, NetBSD, OpenBSD, MacOS X */
39 /* Call the system's fpurge function. */
41 # if !HAVE_DECL_FPURGE
42 extern int fpurge (FILE *);
44 int result = fpurge (fp);
45 # if defined __sferror /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
47 /* Correct the invariants that fpurge broke.
48 <stdio.h> on BSD systems says:
49 "The following always hold: if _flags & __SRD, _w is 0."
50 If this invariant is not fulfilled and the stream is read-write but
51 currently writing, subsequent putc or fputc calls will write directly
52 into the buffer, although they shouldn't be allowed to. */
53 if ((fp->_flags & __SRD) != 0)
60 /* Most systems provide FILE as a struct and the necessary bitmask in
61 <stdio.h>, because they need it for implementing getc() and putc() as
63 # if defined _IO_ferror_unlocked /* GNU libc, BeOS */
64 fp->_IO_read_end = fp->_IO_read_ptr;
65 fp->_IO_write_ptr = fp->_IO_write_base;
66 /* Avoid memory leak when there is an active ungetc buffer. */
67 if (fp->_IO_save_base != NULL)
69 free (fp->_IO_save_base);
70 fp->_IO_save_base = NULL;
73 # elif defined __sferror /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
74 fp->_p = fp->_bf._base;
76 fp->_w = ((fp->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
79 /* Avoid memory leak when there is an active ungetc buffer. */
80 # if defined __NetBSD__ || defined __OpenBSD__ /* NetBSD, OpenBSD */
81 /* See <http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libc/stdio/fileext.h?rev=HEAD&content-type=text/x-cvsweb-markup>
82 and <http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdio/fileext.h?rev=HEAD&content-type=text/x-cvsweb-markup> */
83 # define fp_ub ((struct { struct __sbuf _ub; } *) fp->_ext._base)->_ub
84 # else /* FreeBSD, MacOS X, Cygwin */
85 # define fp_ub fp->_ub
87 if (fp_ub._base != NULL)
89 if (fp_ub._base != fp->_ubuf)
94 # elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
99 # elif defined __UCLIBC__ /* uClibc */
100 # ifdef __STDIO_BUFFERS
101 if (fp->__modeflags & __FLAG_WRITING)
102 fp->__bufpos = fp->__bufstart;
103 else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
104 fp->__bufpos = fp->__bufread;
108 #error "Please port gnulib fpurge.c to your platform! Look at the definitions of fflush, setvbuf and ungetc on your system, then report this to bug-gnulib."