70 lines
1.6 KiB
Groff
70 lines
1.6 KiB
Groff
.\" Copyright (c) 1980 Regents of the University of California.
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.\" All rights reserved. The Berkeley software License Agreement
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.\" specifies the terms and conditions for redistribution.
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.\"
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.\" @(#)ioctl.2 6.3 (Berkeley) 3/4/86
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.\"
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.TH IOCTL 2 "March 4, 1986"
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.UC 4
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.SH NAME
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ioctl \- control device
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.SH SYNOPSIS
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.nf
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.ft B
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#include <sys/types.h>
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#include <sys/ioctl.h>
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.ta +54n
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int ioctl(int \fId\fP, int \fIrequest\fP, void *\fIargp\fP) (Minix)
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int ioctl(int \fId\fP, ioreq_t \fIrequest\fP, void *\fIargp\fP) (Minix-vmd)
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.DT
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.fi
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.ft R
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.SH DESCRIPTION
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.B Ioctl
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performs a variety of functions
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on open descriptors. In particular, many operating
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characteristics of character special files (e.g. terminals)
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may be controlled with
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.B ioctl
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requests.
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The writeups of various devices in section 4 discuss how
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.B ioctl
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applies to them.
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.PP
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An ioctl
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.I request
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has encoded in it whether the argument is an \*(lqin\*(rq parameter
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or \*(lqout\*(rq parameter, and the size of the argument \fIargp\fP in bytes.
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Macros and defines used in specifying an ioctl
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.I request
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are located in the file
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.IR <sys/ioctl.h> .
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.SH "RETURN VALUE
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If an error has occurred, a value of \-1 is returned and
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.B errno
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is set to indicate the error.
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.SH ERRORS
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.B Ioctl
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will fail if one or more of the following are true:
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.TP 15
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[EBADF]
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\fID\fP is not a valid descriptor.
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.TP 15
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[ENOTTY]
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\fID\fP is not associated with a character
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special device.
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.TP 15
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[ENOTTY]
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The specified request does not apply to the kind
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of object that the descriptor \fId\fP references.
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.TP 15
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[EINVAL]
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\fIRequest\fP or \fIargp\fP is not valid.
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.SH "SEE ALSO"
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.BR execve (2),
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.BR fcntl (2),
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.BR mt (4),
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.BR tty (4),
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.BR intro (4).
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