.po 1i
.TH IOCTL 2 Bell
.V 08/15/84 17:13:37
.\"@[$]ioctl.2	1.12	08/15/84 17:13:37 - Zilog Inc.
.SH NAME
ioctl \- input / output control device
.SH SYNOPSIS
.B #include <sys/ioctl.h>
.PP
.B int ioctl
.I (fildes, request, arg)
.br
.B int
.I fildes, request;
.SH DESCRIPTION
.B Ioctl
performs a variety of functions
on character special files (devices).
The writeups of various devices
in Section 4 discuss how
.B ioctl
applies to them.
.PP
.B Ioctl
will fail if one or more of the following are true:
.IP
.I Fildes
is not a valid open file descriptor.
.SM
\%[EBADF]
.IP
.I Fildes
is not associated with a character special device.
.SM
\%[ENOTTY]
.IP
.I Request
or
.I arg
is not valid.
See
.BR tty (4).
.SM
\%[EINVAL]
.SH RETURN VALUE
If an error has occurred,
a value of \-1 is returned and
.B errno
is set to indicate the error.
.SH SEE ALSO
tty(4).
.SH ASSEMBLER
.nf
.na
	CONSTANT IOCTL	:= 54

	...	!* fildes, request in r0, r1 respectively *!
		!* arg in r2 *!
	sc	#IOCTL
	...	!* return value in r4 *!
.fi
.ad