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[glibc.git] / libio / iosetvbuf.c
blob673677191acec4f194b687808feea7e597dcea10
1 /* Copyright (C) 1993, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
2 This file is part of the GNU IO Library.
4 This library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License as
6 published by the Free Software Foundation; either version 2, or (at
7 your option) any later version.
9 This library is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this library; see the file COPYING. If not, write to
16 the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
17 MA 02111-1307, USA.
19 As a special exception, if you link this library with files
20 compiled with a GNU compiler to produce an executable, this does
21 not cause the resulting executable to be covered by the GNU General
22 Public License. This exception does not however invalidate any
23 other reasons why the executable file might be covered by the GNU
24 General Public License. */
26 #include "libioP.h"
28 #define _IOFBF 0 /* Fully buffered. */
29 #define _IOLBF 1 /* Line buffered. */
30 #define _IONBF 2 /* No buffering. */
32 int
33 _IO_setvbuf (fp, buf, mode, size)
34 _IO_FILE *fp;
35 char *buf;
36 int mode;
37 _IO_size_t size;
39 int result;
40 CHECK_FILE (fp, EOF);
41 _IO_cleanup_region_start ((void (*) (void *)) _IO_funlockfile, fp);
42 _IO_flockfile (fp);
43 switch (mode)
45 case _IOFBF:
46 fp->_IO_file_flags &= ~_IO_LINE_BUF|_IO_UNBUFFERED;
47 if (buf == NULL)
49 if (fp->_IO_buf_base == NULL)
51 /* There is no flag to distinguish between "fully buffered
52 mode has been explicitly set" as opposed to "line
53 buffering has not been explicitly set". In both
54 cases, _IO_LINE_BUF is off. If this is a tty, and
55 _IO_filedoalloc later gets called, it cannot know if
56 it should set the _IO_LINE_BUF flag (because that is
57 the default), or not (because we have explicitly asked
58 for fully buffered mode). So we make sure a buffer
59 gets allocated now, and explicitly turn off line
60 buffering.
62 A possibly cleaner alternative would be to add an
63 extra flag, but then flags are a finite resource. */
64 if (_IO_DOALLOCATE (fp) < 0)
66 result = EOF;
67 goto unlock_return;
69 fp->_IO_file_flags &= ~_IO_LINE_BUF;
71 result = 0;
72 goto unlock_return;
74 break;
75 case _IOLBF:
76 fp->_IO_file_flags &= ~_IO_UNBUFFERED;
77 fp->_IO_file_flags |= _IO_LINE_BUF;
78 if (buf == NULL)
80 result = 0;
81 goto unlock_return;
83 break;
84 case _IONBF:
85 buf = NULL;
86 size = 0;
87 break;
88 default:
89 result = EOF;
90 goto unlock_return;
92 result = _IO_SETBUF (fp, buf, size) == NULL ? EOF : 0;
93 if (result == 0 && fp->_vtable_offset == 0 && fp->_mode == 0
94 && _IO_CHECK_WIDE (fp))
95 /* We also have to set the buffer using the wide char function. */
96 result = _IO_WSETBUF (fp, buf, size) == NULL ? EOF : 0;
98 unlock_return:
99 _IO_funlockfile (fp);
100 _IO_cleanup_region_end (0);
101 return result;
104 #ifdef weak_alias
105 weak_alias (_IO_setvbuf, setvbuf)
106 #endif