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.\" $FreeBSD: src/lib/libc/sys/ioctl.2,v 1.7.2.7 2001/12/14 18:34:01 ru Exp $ 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.In sys/ioctl.h 46.Ft int 47.Fn ioctl "int d" "unsigned long request" ... 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 61The third argument to 62.Nm 63is traditionally named 64.Ar "char *argp" . 65Most uses of 66.Nm 67in 68.Fx 3.0 69however, require the third argument to be a 70.Ar caddr_t 71or an 72.Ar int . 73.Pp 74An ioctl 75.Fa request 76has encoded in it whether the argument is an 77.Dq in 78parameter 79or 80.Dq out 81parameter, and the size of the argument 82.Fa argp 83in bytes. 84Macros and defines used in specifying an ioctl 85.Fa request 86are located in the file 87.Ao Pa sys/ioctl.h Ac . 88.Sh RETURN VALUES 89If an error has occurred, a value of -1 is returned and 90.Va errno 91is set to indicate the error. 92.Sh ERRORS 93.Fn ioctl 94will fail if: 95.Bl -tag -width Er 96.It Bq Er EBADF 97.Fa d 98is not a valid descriptor. 99.It Bq Er ENOTTY 100.Fa d 101is not associated with a character 102special device. 103.It Bq Er ENOTTY 104The specified request does not apply to the kind 105of object that the descriptor 106.Fa d 107references. 108.It Bq Er EINVAL 109.Fa request 110or 111.Fa argp 112is not valid. 113.It Bq Er EFAULT 114.Fa argp 115points outside the process's allocated address space. 116.El 117.Sh SEE ALSO 118.Xr execve 2 , 119.Xr fcntl 2 , 120.Xr intro 4 , 121.Xr tty 4 122.Sh HISTORY 123An 124.Fn ioctl 125function call appeared in 126.At v7 . 127