1.\" $NetBSD: ioctl.2,v 1.5 1995/02/27 12:33:47 cgd 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 BSD 4 39.Sh NAME 40.Nm ioctl 41.Nd control device 42.Sh SYNOPSIS 43.Fd #include <sys/ioctl.h> 44.Ft int 45.Fo ioctl 46.Fa "int fildes" 47.Fa "unsigned long request" 48.Fa "..." 49.Fc 50.Sh DESCRIPTION 51The 52.Fn ioctl 53function manipulates the underlying device parameters of special files. 54In particular, many operating 55characteristics of character special files (e.g. terminals) 56may be controlled with 57.Fn ioctl 58requests. 59The argument 60.Fa fildes 61must be an open file descriptor. 62.Pp 63An ioctl 64.Fa request 65has encoded in it whether the argument is an 66.Dq in 67parameter 68or 69.Dq out 70parameter, and the size of the argument 71.Fa argp 72in bytes. 73Macros and defines used in specifying an ioctl 74.Fa request 75are located in the file 76.Ao Pa sys/ioctl.h Ac . 77.Sh RETURN VALUES 78If an error has occurred, a value of -1 is returned and 79.Va errno 80is set to indicate the error. 81.Sh ERRORS 82.Fn ioctl 83will fail if: 84.Bl -tag -width Er 85.\" ========== 86.It Bq Er EBADF 87.Fa fildes 88is not a valid descriptor. 89.\" ========== 90.It Bq Er EINVAL 91.Fa Request 92or 93.Fa argp 94is not valid. 95.\" ========== 96.It Bq Er ENOTTY 97.Fa fildes 98is not associated with a character 99special device. 100.\" ========== 101.It Bq Er ENOTTY 102The specified request does not apply to the kind 103of object that the descriptor 104.Fa fildes 105references. 106.El 107.Sh SEE ALSO 108.Xr cdio 1 , 109.Xr chio 1 , 110.Xr mt 1 , 111.Xr execve 2 , 112.Xr fcntl 2 , 113.Xr intro 4 , 114.Xr tty 4 115.Sh HISTORY 116An 117.Fn ioctl 118function call appeared in 119.At v7 . 120