1/* Copyright (C) 1993, 1996, 1997 Free Software Foundation, Inc. 2 This file is part of the GNU IO Library. 3 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. 8 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. 13 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. 18 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. */ 25 26#include "libioP.h" 27 28#define _IOFBF 0 /* Fully buffered. */ 29#define _IOLBF 1 /* Line buffered. */ 30#define _IONBF 2 /* No buffering. */ 31 32int 33_IO_setvbuf (fp, buf, mode, size) 34 _IO_FILE *fp; 35 char *buf; 36 int mode; 37 _IO_size_t size; 38{ 39 int result; 40 CHECK_FILE (fp, EOF); 41 _IO_cleanup_region_start ((void (*) __P ((void *))) _IO_funlockfile, fp); 42 _IO_flockfile (fp); 43 switch (mode) 44 { 45 case _IOFBF: 46 fp->_IO_file_flags &= ~_IO_LINE_BUF|_IO_UNBUFFERED; 47 if (buf == NULL) 48 { 49 if (fp->_IO_buf_base == NULL) 50 { 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. 61 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) 65 { 66 result = EOF; 67 goto unlock_return; 68 } 69 fp->_IO_file_flags &= ~_IO_LINE_BUF; 70 } 71 result = 0; 72 goto unlock_return; 73 } 74 break; 75 case _IOLBF: 76 fp->_IO_file_flags &= ~_IO_UNBUFFERED; 77 fp->_IO_file_flags |= _IO_LINE_BUF; 78 if (buf == NULL) 79 { 80 result = 0; 81 goto unlock_return; 82 } 83 break; 84 case _IONBF: 85 buf = NULL; 86 size = 0; 87 break; 88 default: 89 result = EOF; 90 goto unlock_return; 91 } 92 result = _IO_SETBUF (fp, buf, size) == NULL ? EOF : 0; 93unlock_return: 94 _IO_cleanup_region_end (1); 95 return result; 96} 97 98#ifdef weak_alias 99weak_alias (_IO_setvbuf, setvbuf) 100#endif 101