1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. 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.\" @(#)ioctl.2 8.2 (Berkeley) 12/11/93 33.\" 34.Dd December 11, 1993 35.Dt IOCTL 2 36.Os BSD 4 37.Sh NAME 38.Nm ioctl 39.Nd control device 40.Sh SYNOPSIS 41.Fd #include <sys/ioctl.h> 42.Ft int 43.Fn ioctl "int d" "unsigned long request" "char *argp" 44.Sh DESCRIPTION 45The 46.Fn ioctl 47function manipulates the underlying device parameters of special files. 48In particular, many operating 49characteristics of character special files (e.g. terminals) 50may be controlled with 51.Fn ioctl 52requests. 53The argument 54.Fa d 55must be an open file descriptor. 56.Pp 57An ioctl 58.Fa request 59has encoded in it whether the argument is an 60.Dq in 61parameter 62or 63.Dq out 64parameter, and the size of the argument 65.Fa argp 66in bytes. 67Macros and defines used in specifying an ioctl 68.Fa request 69are located in the file 70.Ao Pa sys/ioctl.h Ac . 71.Sh RETURN VALUES 72If an error has occurred, a value of -1 is returned and 73.Va errno 74is set to indicate the error. 75.Sh ERRORS 76.Fn Ioctl 77will fail if: 78.Bl -tag -width [ENOTTY] 79.It Bq Er EBADF 80.Fa d 81is not a valid descriptor. 82.It Bq Er ENOTTY 83.Fa d 84is not associated with a character 85special device. 86.It Bq Er ENOTTY 87The specified request does not apply to the kind 88of object that the descriptor 89.Fa d 90references. 91.It Bq Er EINVAL 92.Fa Request 93or 94.Fa argp 95is not valid. 96.El 97.Sh SEE ALSO 98.Xr mt 1 , 99.Xr execve 2 , 100.Xr fcntl 2 , 101.Xr tty 4 , 102.Xr intro 4 103.Sh HISTORY 104An 105.Nm 106function call appeared in Version 7 AT&T UNIX. 107