summaryrefslogtreecommitdiffstats
path: root/lib/fpurge.c
blob: 21e3b862ea85078b5bbcc325c7ef42219eb84a5e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
/* Flushing buffers of a FILE stream.
   Copyright (C) 2007-2022 Free Software Foundation, Inc.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include <stdio.h>

#if HAVE___FPURGE                   /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
# if HAVE_STDIO_EXT_H
#  include <stdio_ext.h>
# endif
#endif
#include <stdlib.h>

#include "stdio-impl.h"

int
fpurge (FILE *fp)
{
#if HAVE___FPURGE                   /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */

  __fpurge (fp);
  /* The __fpurge function does not have a return value.  */
  return 0;

#elif HAVE_FPURGE                   /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin >= 1.7 */

  /* Call the system's fpurge function.  */
# undef fpurge
# if !HAVE_DECL_FPURGE
  extern int fpurge (FILE *);
# endif
  int result = fpurge (fp);
# if defined __sferror || defined __DragonFly__ || defined __ANDROID__
  /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
  if (result == 0)
    /* Correct the invariants that fpurge broke.
       <stdio.h> on BSD systems says:
         "The following always hold: if _flags & __SRD, _w is 0."
       If this invariant is not fulfilled and the stream is read-write but
       currently reading, subsequent putc or fputc calls will write directly
       into the buffer, although they shouldn't be allowed to.  */
    if ((fp_->_flags & __SRD) != 0)
      fp_->_w = 0;
# endif
  return result;

#else

  /* Most systems provide FILE as a struct and the necessary bitmask in
     <stdio.h>, because they need it for implementing getc() and putc() as
     fast macros.  */
# if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
  /* GNU libc, BeOS, Haiku, Linux libc5 */
  fp->_IO_read_end = fp->_IO_read_ptr;
  fp->_IO_write_ptr = fp->_IO_write_base;
  /* Avoid memory leak when there is an active ungetc buffer.  */
  if (fp->_IO_save_base != NULL)
    {
      free (fp->_IO_save_base);
      fp->_IO_save_base = NULL;
    }
  return 0;
# elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
  /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
  fp_->_p = fp_->_bf._base;
  fp_->_r = 0;
  fp_->_w = ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
             ? fp_->_bf._size
             : 0);
  /* Avoid memory leak when there is an active ungetc buffer.  */
  if (fp_ub._base != NULL)
    {
      if (fp_ub._base != fp_->_ubuf)
        free (fp_ub._base);
      fp_ub._base = NULL;
    }
  return 0;
# elif defined __EMX__              /* emx+gcc */
  fp->_ptr = fp->_buffer;
  fp->_rcount = 0;
  fp->_wcount = 0;
  fp->_ungetc_count = 0;
  return 0;
# elif defined __minix              /* Minix */
  fp->_ptr = fp->_buf;
  if (fp->_ptr != NULL)
    fp->_count = 0;
  return 0;
# elif defined _IOERR               /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
  fp_->_ptr = fp_->_base;
  if (fp_->_ptr != NULL)
    fp_->_cnt = 0;
  return 0;
# elif defined __UCLIBC__           /* uClibc */
#  ifdef __STDIO_BUFFERS
  if (fp->__modeflags & __FLAG_WRITING)
    fp->__bufpos = fp->__bufstart;
  else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
    fp->__bufpos = fp->__bufread;
#  endif
  return 0;
# elif defined __QNX__              /* QNX */
  fp->_Rback = fp->_Back + sizeof (fp->_Back);
  fp->_Rsave = NULL;
  if (fp->_Mode & 0x2000 /* _MWRITE */)
    /* fp->_Buf <= fp->_Next <= fp->_Wend */
    fp->_Next = fp->_Buf;
  else
    /* fp->_Buf <= fp->_Next <= fp->_Rend */
    fp->_Rend = fp->_Next;
  return 0;
# elif defined __MINT__             /* Atari FreeMiNT */
  if (fp->__pushed_back)
    {
      fp->__bufp = fp->__pushback_bufp;
      fp->__pushed_back = 0;
    }
  /* Preserve the current file position.  */
  if (fp->__target != -1)
    fp->__target += fp->__bufp - fp->__buffer;
  fp->__bufp = fp->__buffer;
  /* Nothing in the buffer, next getc is nontrivial.  */
  fp->__get_limit = fp->__bufp;
  /* Nothing in the buffer, next putc is nontrivial.  */
  fp->__put_limit = fp->__buffer;
  return 0;
# elif defined EPLAN9               /* Plan9 */
  fp->rp = fp->wp = fp->lp = fp->buf;
  return 0;
# else
#  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."
# endif

#endif
}