1 /* Flushing buffers of a FILE stream.
2 Copyright (C) 2007-2012 Free Software Foundation, Inc.
3
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.
8
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.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17 #include <config.h>
18
19 /* Specification. */
20 #include <stdio.h>
21
22 #if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7 */
23 # include <stdio_ext.h>
24 #endif
25 #include <stdlib.h>
26
27 #include "stdio-impl.h"
28
29 int
fpurge(FILE * fp)30 fpurge (FILE *fp)
31 {
32 #if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7 */
33
34 __fpurge (fp);
35 /* The __fpurge function does not have a return value. */
36 return 0;
37
38 #elif HAVE_FPURGE /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin 1.7 */
39
40 /* Call the system's fpurge function. */
41 # undef fpurge
42 # if !HAVE_DECL_FPURGE
43 extern int fpurge (FILE *);
44 # endif
45 int result = fpurge (fp);
46 # if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
47 if (result == 0)
48 /* Correct the invariants that fpurge broke.
49 <stdio.h> on BSD systems says:
50 "The following always hold: if _flags & __SRD, _w is 0."
51 If this invariant is not fulfilled and the stream is read-write but
52 currently reading, subsequent putc or fputc calls will write directly
53 into the buffer, although they shouldn't be allowed to. */
54 if ((fp_->_flags & __SRD) != 0)
55 fp_->_w = 0;
56 # endif
57 return result;
58
59 #else
60
61 /* Most systems provide FILE as a struct and the necessary bitmask in
62 <stdio.h>, because they need it for implementing getc() and putc() as
63 fast macros. */
64 # if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
65 fp->_IO_read_end = fp->_IO_read_ptr;
66 fp->_IO_write_ptr = fp->_IO_write_base;
67 /* Avoid memory leak when there is an active ungetc buffer. */
68 if (fp->_IO_save_base != NULL)
69 {
70 free (fp->_IO_save_base);
71 fp->_IO_save_base = NULL;
72 }
73 return 0;
74 # elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
75 fp_->_p = fp_->_bf._base;
76 fp_->_r = 0;
77 fp_->_w = ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
78 ? fp_->_bf._size
79 : 0);
80 /* Avoid memory leak when there is an active ungetc buffer. */
81 if (fp_ub._base != NULL)
82 {
83 if (fp_ub._base != fp_->_ubuf)
84 free (fp_ub._base);
85 fp_ub._base = NULL;
86 }
87 return 0;
88 # elif defined __EMX__ /* emx+gcc */
89 fp->_ptr = fp->_buffer;
90 fp->_rcount = 0;
91 fp->_wcount = 0;
92 fp->_ungetc_count = 0;
93 return 0;
94 # elif defined __minix /* Minix */
95 fp->_ptr = fp->_buf;
96 if (fp->_ptr != NULL)
97 fp->_count = 0;
98 return 0;
99 # elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, NonStop Kernel */
100 fp->_ptr = fp->_base;
101 if (fp->_ptr != NULL)
102 fp->_cnt = 0;
103 return 0;
104 # elif defined __UCLIBC__ /* uClibc */
105 # ifdef __STDIO_BUFFERS
106 if (fp->__modeflags & __FLAG_WRITING)
107 fp->__bufpos = fp->__bufstart;
108 else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
109 fp->__bufpos = fp->__bufread;
110 # endif
111 return 0;
112 # elif defined __QNX__ /* QNX */
113 fp->_Rback = fp->_Back + sizeof (fp->_Back);
114 fp->_Rsave = NULL;
115 if (fp->_Mode & 0x2000 /* _MWRITE */)
116 /* fp->_Buf <= fp->_Next <= fp->_Wend */
117 fp->_Next = fp->_Buf;
118 else
119 /* fp->_Buf <= fp->_Next <= fp->_Rend */
120 fp->_Rend = fp->_Next;
121 return 0;
122 # elif defined __MINT__ /* Atari FreeMiNT */
123 if (fp->__pushed_back)
124 {
125 fp->__bufp = fp->__pushback_bufp;
126 fp->__pushed_back = 0;
127 }
128 /* Preserve the current file position. */
129 if (fp->__target != -1)
130 fp->__target += fp->__bufp - fp->__buffer;
131 fp->__bufp = fp->__buffer;
132 /* Nothing in the buffer, next getc is nontrivial. */
133 fp->__get_limit = fp->__bufp;
134 /* Nothing in the buffer, next putc is nontrivial. */
135 fp->__put_limit = fp->__buffer;
136 return 0;
137 # else
138 # 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."
139 # endif
140
141 #endif
142 }
143