79 lines
2.6 KiB
C
79 lines
2.6 KiB
C
/*
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Copyright (C) 1993 Free Software Foundation
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This file is part of the GNU IO Library. This library is free
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software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option)
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any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this library; see the file COPYING. If not, write to the Free
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Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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As a special exception, if you link this library with files
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compiled with a GNU compiler to produce an executable, this does not cause
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the resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why
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the executable file might be covered by the GNU General Public License. */
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#include "libioP.h"
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#define _IOFBF 0 /* Fully buffered. */
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#define _IOLBF 1 /* Line buffered. */
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#define _IONBF 2 /* No buffering. */
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int
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DEFUN(_IO_setvbuf, (fp, buf, mode, size),
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_IO_FILE* fp AND char* buf AND int mode AND _IO_size_t size)
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{
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CHECK_FILE(fp, EOF);
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switch (mode)
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{
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case _IOFBF:
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fp->_IO_file_flags &= ~_IO_LINE_BUF|_IO_UNBUFFERED;
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if (buf == NULL)
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{
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if (fp->_IO_buf_base == NULL)
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{
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/* There is no flag to distinguish between "fully buffered
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mode has been explicitly set" as opposed to "line
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buffering has not been explicitly set". In both
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cases, _IO_LINE_BUF is off. If this is a tty, and
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_IO_filedoalloc later gets called, it cannot know if
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it should set the _IO_LINE_BUF flag (because that is
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the default), or not (because we have explicitly asked
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for fully buffered mode). So we make sure a buffer
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gets allocated now, and explicitly turn off line
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buffering.
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A possibly cleaner alternative would be to add an
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extra flag, but then flags are a finite resource. */
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if (_IO_DOALLOCATE (fp) < 0)
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return EOF;
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fp->_IO_file_flags &= ~_IO_LINE_BUF;
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}
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return 0;
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}
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break;
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case _IOLBF:
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fp->_IO_file_flags &= ~_IO_UNBUFFERED;
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fp->_IO_file_flags |= _IO_LINE_BUF;
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if (buf == NULL)
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return 0;
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break;
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case _IONBF:
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buf = NULL;
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size = 0;
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break;
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default:
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return EOF;
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}
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return _IO_SETBUF (fp, buf, size) == NULL ? EOF : 0;
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}
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