@node setbuffer, stdio
@subheading Syntax

@example
#include <stdio.h>

void setbuffer(FILE *file, char *buffer, int length);
@end example

@subheading Description

This function modifies the buffering characteristics of @var{file}. 
First, if the file already has a buffer, it is freed.  If there was any
pending data in it, it is lost, so this function should only be used
immediately after a call to @code{fopen}.

If the @var{buffer} passed is @code{NULL}, the file is set to
unbuffered.  If a non-@code{NULL} buffer is passed, it must be at least
@var{size} bytes in size, and the file is set to fully buffered.

@xref{setbuf}.
@xref{setlinebuf}.
@xref{setvbuf}.

@subheading Return Value

None.

@subheading Portability

@portability !ansi, !posix

@subheading Example

@example
setbuffer(stdout, malloc(10000), 10000);
@end example