1 /* fpurge - Flushing buffers of a FILE stream. */
3 /* Copyright (C) 2007 Free Software Foundation, Inc.
5 This file is part of GNU Bash, the Bourne Again SHell.
7 Bash is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 Bash is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with Bash. If not, see <http://www.gnu.org/licenses/>.
27 /* Specification. Same as in ../../externs.h. */
28 #define NEED_FPURGE_DECL
30 # define fpurge _bash_fpurge
32 extern int fpurge __P((FILE *stream));
34 #if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7 */
35 # include <stdio_ext.h>
42 #if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7 */
45 /* The __fpurge function does not have a return value. */
48 #elif HAVE_FPURGE /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X */
50 /* Call the system's fpurge function. */
52 # if !HAVE_DECL_FPURGE
53 extern int fpurge (FILE *);
55 int result = fpurge (fp);
56 # if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
58 /* Correct the invariants that fpurge broke.
59 <stdio.h> on BSD systems says:
60 "The following always hold: if _flags & __SRD, _w is 0."
61 If this invariant is not fulfilled and the stream is read-write but
62 currently writing, subsequent putc or fputc calls will write directly
63 into the buffer, although they shouldn't be allowed to. */
64 if ((fp->_flags & __SRD) != 0)
71 /* Most systems provide FILE as a struct and the necessary bitmask in
72 <stdio.h>, because they need it for implementing getc() and putc() as
74 # if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
75 fp->_IO_read_end = fp->_IO_read_ptr;
76 fp->_IO_write_ptr = fp->_IO_write_base;
77 /* Avoid memory leak when there is an active ungetc buffer. */
78 if (fp->_IO_save_base != NULL)
80 free (fp->_IO_save_base);
81 fp->_IO_save_base = NULL;
84 # elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
85 fp_->_p = fp_->_bf._base;
87 fp_->_w = ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
90 /* Avoid memory leak when there is an active ungetc buffer. */
91 if (fp_ub._base != NULL)
93 if (fp_ub._base != fp_->_ubuf)
98 # elif defined __EMX__ /* emx+gcc */
99 fp->_ptr = fp->_buffer;
102 fp->_ungetc_count = 0;
104 # elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */
105 fp->_ptr = fp->_base;
106 if (fp->_ptr != NULL)
109 # elif defined __UCLIBC__ /* uClibc */
110 # ifdef __STDIO_BUFFERS
111 if (fp->__modeflags & __FLAG_WRITING)
112 fp->__bufpos = fp->__bufstart;
113 else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
114 fp->__bufpos = fp->__bufread;
117 # elif defined __QNX__ /* QNX */
118 fp->_Rback = fp->_Back + sizeof (fp->_Back);
120 if (fp->_Mode & 0x2000 /* _MWRITE */)
121 /* fp->_Buf <= fp->_Next <= fp->_Wend */
122 fp->_Next = fp->_Buf;
124 /* fp->_Buf <= fp->_Next <= fp->_Rend */
125 fp->_Rend = fp->_Next;
127 # elif defined __MINT__ /* Atari FreeMiNT */
128 if (fp->__pushed_back)
130 fp->__bufp = fp->__pushback_bufp;
131 fp->__pushed_back = 0;
133 /* Preserve the current file position. */
134 if (fp->__target != -1)
135 fp->__target += fp->__bufp - fp->__buffer;
136 fp->__bufp = fp->__buffer;
137 /* Nothing in the buffer, next getc is nontrivial. */
138 fp->__get_limit = fp->__bufp;
139 /* Nothing in the buffer, next putc is nontrivial. */
140 fp->__put_limit = fp->__buffer;
143 # warning "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."