1 /* Copyright (C) 1993,96,97,98,99,2000,2001,2002 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library 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 GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, write to the Free 16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 17 02111-1307 USA. 18 19 As a special exception, if you link the code in this file with 20 files compiled with a GNU compiler to produce an executable, 21 that does not cause the resulting executable to be covered by 22 the GNU Lesser General Public License. This exception does not 23 however invalidate any other reasons why the executable file 24 might be covered by the GNU Lesser General Public License. 25 This exception applies to code released by its copyright holders 26 in files containing the exception. */ 27 28 #include "libioP.h" 29 30 #define _IOFBF 0 /* Fully buffered. */ 31 #define _IOLBF 1 /* Line buffered. */ 32 #define _IONBF 2 /* No buffering. */ 33 34 int 35 _IO_setvbuf (fp, buf, mode, size) 36 _IO_FILE *fp; 37 char *buf; 38 int mode; 39 _IO_size_t size; 40 { 41 int result; 42 CHECK_FILE (fp, EOF); 43 _IO_cleanup_region_start ((void (*) (void *)) _IO_funlockfile, fp); 44 _IO_flockfile (fp); 45 switch (mode) 46 { 47 case _IOFBF: 48 fp->_IO_file_flags &= ~_IO_LINE_BUF|_IO_UNBUFFERED; 49 if (buf == NULL) 50 { 51 if (fp->_IO_buf_base == NULL) 52 { 53 /* There is no flag to distinguish between "fully buffered 54 mode has been explicitly set" as opposed to "line 55 buffering has not been explicitly set". In both 56 cases, _IO_LINE_BUF is off. If this is a tty, and 57 _IO_filedoalloc later gets called, it cannot know if 58 it should set the _IO_LINE_BUF flag (because that is 59 the default), or not (because we have explicitly asked 60 for fully buffered mode). So we make sure a buffer 61 gets allocated now, and explicitly turn off line 62 buffering. 63 64 A possibly cleaner alternative would be to add an 65 extra flag, but then flags are a finite resource. */ 66 if (_IO_DOALLOCATE (fp) < 0) 67 { 68 result = EOF; 69 goto unlock_return; 70 } 71 fp->_IO_file_flags &= ~_IO_LINE_BUF; 72 } 73 result = 0; 74 goto unlock_return; 75 } 76 break; 77 case _IOLBF: 78 fp->_IO_file_flags &= ~_IO_UNBUFFERED; 79 fp->_IO_file_flags |= _IO_LINE_BUF; 80 if (buf == NULL) 81 { 82 result = 0; 83 goto unlock_return; 84 } 85 break; 86 case _IONBF: 87 fp->_IO_file_flags &= ~_IO_LINE_BUF; 88 fp->_IO_file_flags |= _IO_UNBUFFERED; 89 buf = NULL; 90 size = 0; 91 break; 92 default: 93 result = EOF; 94 goto unlock_return; 95 } 96 result = _IO_SETBUF (fp, buf, size) == NULL ? EOF : 0; 97 98 unlock_return: 99 _IO_funlockfile (fp); 100 _IO_cleanup_region_end (0); 101 return result; 102 } 103 INTDEF(_IO_setvbuf) 104 105 #ifdef weak_alias 106 weak_alias (_IO_setvbuf, setvbuf) 107 #endif 108