1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)ioctl.2 6.4 (Berkeley) 3/10/91 33.\" $Id: ioctl.2,v 1.4 1993/11/29 21:25:15 jtc Exp $ 34.\" 35.Dd March 10, 1991 36.Dt IOCTL 2 37.Os BSD 4 38.Sh NAME 39.Nm ioctl 40.Nd control device 41.Sh SYNOPSIS 42.Fd #include <sys/ioctl.h> 43.Ft int 44.Fn ioctl "int d" "unsigned long request" "char *argp" 45.Sh DESCRIPTION 46The 47.Fn ioctl 48function manipulates the underlying device parameters of special files. 49In particular, many operating 50characteristics of character special files (e.g. terminals) 51may be controlled with 52.Fn ioctl 53requests. 54The argument 55.Fa d 56must be an open file descriptor. 57.Pp 58An ioctl 59.Fa request 60has encoded in it whether the argument is an 61.Dq in 62parameter 63or 64.Dq out 65parameter, and the size of the argument 66.Fa argp 67in bytes. 68Macros and defines used in specifying an ioctl 69.Fa request 70are located in the file 71.Ao Pa sys/ioctl.h Ac . 72.Sh RETURN VALUES 73If an error has occurred, a value of -1 is returned and 74.Va errno 75is set to indicate the error. 76.Sh ERRORS 77.Fn Ioctl 78will fail: 79.Bl -tag -width Er 80.It Bq Er EBADF 81.Fa d 82is not a valid descriptor. 83.It Bq Er ENOTTY 84.Fa d 85is not associated with a character 86special device. 87.It Bq Er ENOTTY 88The specified request does not apply to the kind 89of object that the descriptor 90.Fa d 91references. 92.It Bq Er EINVAL 93.Fa Request 94or 95.Fa argp 96is not valid. 97.El 98.Sh SEE ALSO 99.Xr execve 2 , 100.Xr fcntl 2 , 101.Xr mt 4 , 102.Xr tty 4 , 103.Xr intro 4 104.Sh HISTORY 105An 106.Fn ioctl 107function call appeared in 108.At v7 . 109