term% cat index.txt SETBUF(3S) SETBUF(3S)
NAME
setbuf - assign buffering to a stream
SYNOPSIS
#include <stdio.h>
setbuf(stream, buf)
FILE *stream;
unsigned char *buf;
DESCRIPTION
Setbuf is used after a stream has been opened but before it is read or
written. It causes the character array buf to be used instead of an
automatically allocated buffer. If buf is the constant pointer NULL,
input/output will be completely unbuffered.
A manifest constant BUFSIZ tells how big an array is needed:
unsigned char buf[BUFSIZ];
A buffer is normally obtained from malloc(3) upon the first getc or
putc(3) on the file, except that the standard output is line buffered
when directed to a terminal. Other output streams directed to termi‐
nals, and the standard error stream stderr are normally not buffered.
If the standard output is line buffered, then it is flushed each time
data is read from the standard input by read(2).
SEE ALSO
fopen(3), getc(3), putc(3), malloc(3)
SETBUF(3S)