setbuf
[specify full buffering for a file
or stream]
SYNOPSIS
#include
<stdio.h>
void setbuf(FILE
*fp, char
*buf);
DESCRIPTION
setbuf
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,
BUFSIZ,
specified in stdio.h).
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, BUFSIZ. You can also use NULL as the value of buf, to signal that the setbuf function is to allocate the buffer.
Warning: You may only use setbuf 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
setbuf
does not return a result.
COMPLIANCE
Both ANSI C and the System V Interface Definition (Issue 2) require
setbuf.
However, they differ on the meaning of a NULL
buffer pointer: the SVID issue 2 specification
says that a NULL
buffer pointer requests unbuffered
output. For maximum portability, avoid NULL
buffer pointers.
Supporting OS subroutines required: close, fstat, isatty, lseek, read, sbrk, write.
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