setbuffer.c

Newlib 嵌入式 C库 标准实现代码

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
/* 
Modified copy of setbuf.c to support the setbuffer function
defined as part of BSD.
Modifications by Gareth Pearce, 2001.
*/

/*
FUNCTION
<<setbuffer>>---specify full buffering for a file or stream with size

INDEX
	setbuffer

ANSI_SYNOPSIS
	#include <stdio.h>
	void setbuffer(FILE *<[fp]>, char *<[buf]>, int <[size]>);

TRAD_SYNOPSIS
	#include <stdio.h>
	void setbuffer(<[fp]>, <[buf]>, <[size]>)
	FILE *<[fp]>;
	char *<[buf]>;
	int <[size]>;

DESCRIPTION
<<setbuffer>> specifies that output to the file or stream identified by
<[fp]> should be fully buffered.  All output for this file will go to a
buffer (of size <[size]>).  Output will be passed on to the host system
only when the buffer is full, or when an input operation intervenes.

You may, if you wish, supply your own buffer by passing a pointer to
it as the argument <[buf]>.  It must have size <[size]>.  You can
also use <<NULL>> as the value of <[buf]>, to signal that the
<<setbuffer>> function is to allocate the buffer.

WARNINGS
You may only use <<setbuffer>> before performing any file operation
other than opening the file.

If you supply a non-null <[buf]>, you must ensure that the associated
storage continues to be available until you close the stream
identified by <[fp]>.

RETURNS
<<setbuffer>> does not return a result.

PORTABILITY
This function comes from BSD not ANSI or POSIX.

Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/

#include <_ansi.h>
#include <stdio.h>
#include "local.h"

_VOID
_DEFUN(setbuffer, (fp, buf, size),
       FILE * fp _AND
       char *buf _AND
       int size)
{
  _CAST_VOID setvbuf (fp, buf, buf ? _IOFBF : _IONBF, (size_t) size);
}