| 1 | .\" Copyright (c) 1980 Regents of the University of California.
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| 2 | .\" All rights reserved. The Berkeley software License Agreement
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| 3 | .\" specifies the terms and conditions for redistribution.
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| 4 | .\"
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| 5 | .\" @(#)ioctl.2 6.3 (Berkeley) 3/4/86
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| 6 | .\"
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| 7 | .TH IOCTL 2 "March 4, 1986"
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| 8 | .UC 4
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| 9 | .SH NAME
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| 10 | ioctl \- control device
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| 11 | .SH SYNOPSIS
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| 12 | .nf
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| 13 | .ft B
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| 14 | #include <sys/types.h>
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| 15 | #include <sys/ioctl.h>
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| 16 |
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| 17 | .ta +54n
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| 18 | int ioctl(int \fId\fP, int \fIrequest\fP, void *\fIargp\fP) (Minix)
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| 19 | int ioctl(int \fId\fP, ioreq_t \fIrequest\fP, void *\fIargp\fP) (Minix-vmd)
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| 20 | .DT
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| 21 | .fi
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| 22 | .ft R
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| 23 | .SH DESCRIPTION
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| 24 | .B Ioctl
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| 25 | performs a variety of functions
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| 26 | on open descriptors. In particular, many operating
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| 27 | characteristics of character special files (e.g. terminals)
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| 28 | may be controlled with
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| 29 | .B ioctl
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| 30 | requests.
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| 31 | The writeups of various devices in section 4 discuss how
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| 32 | .B ioctl
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| 33 | applies to them.
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| 34 | .PP
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| 35 | An ioctl
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| 36 | .I request
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| 37 | has encoded in it whether the argument is an \*(lqin\*(rq parameter
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| 38 | or \*(lqout\*(rq parameter, and the size of the argument \fIargp\fP in bytes.
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| 39 | Macros and defines used in specifying an ioctl
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| 40 | .I request
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| 41 | are located in the file
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| 42 | .IR <sys/ioctl.h> .
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| 43 | .SH "RETURN VALUE
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| 44 | If an error has occurred, a value of \-1 is returned and
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| 45 | .B errno
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| 46 | is set to indicate the error.
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| 47 | .SH ERRORS
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| 48 | .B Ioctl
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| 49 | will fail if one or more of the following are true:
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| 50 | .TP 15
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| 51 | [EBADF]
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| 52 | \fID\fP is not a valid descriptor.
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| 53 | .TP 15
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| 54 | [ENOTTY]
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| 55 | \fID\fP is not associated with a character
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| 56 | special device.
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| 57 | .TP 15
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| 58 | [ENOTTY]
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| 59 | The specified request does not apply to the kind
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| 60 | of object that the descriptor \fId\fP references.
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| 61 | .TP 15
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| 62 | [EINVAL]
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| 63 | \fIRequest\fP or \fIargp\fP is not valid.
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| 64 | .SH "SEE ALSO"
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| 65 | .BR execve (2),
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| 66 | .BR fcntl (2),
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| 67 | .BR mt (4),
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| 68 | .BR tty (4),
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| 69 | .BR intro (4).
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