.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)ioctl.2 6.3 (Berkeley) %G%
performs a variety of functions
on open descriptors. In particular, many operating
characteristics of character special files (e.g. terminals)
The writeups of various devices in section 4 discuss how
has encoded in it whether the argument is an \*(lqin\*(rq parameter
or \*(lqout\*(rq parameter, and the size of the argument \fIargp\fP in bytes.
Macros and defines used in specifying an ioctl
If an error has occurred, a value of \-1 is returned and
is set to indicate the error.
will fail if one or more of the following are true:
\fID\fP is not a valid descriptor.
\fID\fP is not associated with a character
The specified request does not apply to the kind
of object that the descriptor \fId\fP references.
\fIRequest\fP or \fIargp\fP is not valid.
execve(2), fcntl(2), mt(4), tty(4), intro(4N)