1 /* Flushing buffers of a FILE stream.
2 Copyright (C) 2007-2020 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 3 of the License, or
7 (at your option) any later version.
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, see <https://www.gnu.org/licenses/>. */
22 #if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
24 # include <stdio_ext.h>
29 #include "stdio-impl.h"
34 #if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
37 /* The __fpurge function does not have a return value. */
40 #elif HAVE_FPURGE /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin >= 1.7 */
42 /* Call the system's fpurge function. */
44 # if !HAVE_DECL_FPURGE
45 extern int fpurge (FILE *);
47 int result
= fpurge (fp
);
48 # if defined __sferror || defined __DragonFly__ || defined __ANDROID__
49 /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
51 /* Correct the invariants that fpurge broke.
52 <stdio.h> on BSD systems says:
53 "The following always hold: if _flags & __SRD, _w is 0."
54 If this invariant is not fulfilled and the stream is read-write but
55 currently reading, subsequent putc or fputc calls will write directly
56 into the buffer, although they shouldn't be allowed to. */
57 if ((fp_
->_flags
& __SRD
) != 0)
64 /* Most systems provide FILE as a struct and the necessary bitmask in
65 <stdio.h>, because they need it for implementing getc() and putc() as
67 # if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
68 /* GNU libc, BeOS, Haiku, Linux libc5 */
69 fp
->_IO_read_end
= fp
->_IO_read_ptr
;
70 fp
->_IO_write_ptr
= fp
->_IO_write_base
;
71 /* Avoid memory leak when there is an active ungetc buffer. */
72 if (fp
->_IO_save_base
!= NULL
)
74 free (fp
->_IO_save_base
);
75 fp
->_IO_save_base
= NULL
;
78 # elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
79 /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
80 fp_
->_p
= fp_
->_bf
._base
;
82 fp_
->_w
= ((fp_
->_flags
& (__SLBF
| __SNBF
| __SRD
)) == 0 /* fully buffered and not currently reading? */
85 /* Avoid memory leak when there is an active ungetc buffer. */
86 if (fp_ub
._base
!= NULL
)
88 if (fp_ub
._base
!= fp_
->_ubuf
)
93 # elif defined __EMX__ /* emx+gcc */
94 fp
->_ptr
= fp
->_buffer
;
97 fp
->_ungetc_count
= 0;
99 # elif defined __minix /* Minix */
101 if (fp
->_ptr
!= NULL
)
104 # elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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
;
142 # elif defined EPLAN9 /* Plan9 */
143 fp
->rp
= fp
->wp
= fp
->lp
= fp
->buf
;
146 # 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."