1.\" $NetBSD: ioctl.2,v 1.12 2002/02/08 01:28:18 ross Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)ioctl.2 8.2 (Berkeley) 12/11/93 35.\" 36.Dd December 11, 1993 37.Dt IOCTL 2 38.Os 39.Sh NAME 40.Nm ioctl 41.Nd control device 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]sys/ioctl.h\*[Gt] 46.Ft int 47.Fn ioctl "int d" "unsigned long request" "void *argp" 48.Sh DESCRIPTION 49The 50.Fn ioctl 51function manipulates the underlying device parameters of special files. 52In particular, many operating 53characteristics of character special files (e.g. terminals) 54may be controlled with 55.Fn ioctl 56requests. 57The argument 58.Fa d 59must be an open file descriptor. 60.Pp 61An ioctl 62.Fa request 63has encoded in it whether the argument is an 64.Dq in 65parameter 66or 67.Dq out 68parameter, and the size of the argument 69.Fa argp 70in bytes. 71Macros and defines used in specifying an ioctl 72.Fa request 73are located in the file 74.Ao Pa sys/ioctl.h Ac . 75.Sh RETURN VALUES 76If an error has occurred, a value of -1 is returned and 77.Va errno 78is set to indicate the error. 79.Sh ERRORS 80.Fn ioctl 81will fail if: 82.Bl -tag -width Er 83.It Bq Er EBADF 84.Fa d 85is not a valid descriptor. 86.It Bq Er ENOTTY 87.Fa d 88is not associated with a character 89special device. 90.It Bq Er ENOTTY 91The specified request does not apply to the kind 92of object that the descriptor 93.Fa d 94references. 95.It Bq Er EINVAL 96.Fa request 97or 98.Fa argp 99is not valid. 100.El 101.Sh SEE ALSO 102.Xr mt 1 , 103.Xr execve 2 , 104.Xr fcntl 2 , 105.Xr intro 4 , 106.Xr tty 4 107.Sh HISTORY 108An 109.Fn ioctl 110function call appeared in 111.At v7 . 112