projects / unix-history / blame
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1 | .\" Copyright (c) 1980 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| 13111d1e | 5 | .\" @(#)ioctl.2 6.1 (Berkeley) %G% |
| 384b8076 | 6 | .\" |
| 13111d1e | 7 | .TH IOCTL 2 "" |
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8 | .UC 4 |
| 9 | .SH NAME | |
| 6234b5e5 | 10 | ioctl \- control device |
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11 | .SH SYNOPSIS |
| 12 | .nf | |
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13 | .ft B |
| 14 | #include <sys/ioctl.h> | |
| 384b8076 | 15 | .PP |
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16 | .ft B |
| 17 | ioctl(d, request, argp) | |
| 18 | int d, request; | |
| 19 | char *argp; | |
| 384b8076 | 20 | .fi |
| 6234b5e5 | 21 | .ft R |
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22 | .SH DESCRIPTION |
| 23 | .I Ioctl | |
| 24 | performs a variety of functions | |
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25 | on open descriptors. In particular, many operating |
| 26 | characteristics of character special files (e.g. terminals) | |
| 27 | may be controlled with | |
| 28 | .I ioctl | |
| 29 | requests. | |
| 30 | The writeups of various devices in section 4 discuss how | |
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31 | .I ioctl |
| 32 | applies to them. | |
| 33 | .PP | |
| 6234b5e5 | 34 | An ioctl |
| 384b8076 | 35 | .I request |
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36 | has encoded in it whether the argument is an \*(lqin\*(rq parameter |
| 37 | or \*(lqout\*(rq parameter, and the size of the argument \fIargp\fP in bytes. | |
| 38 | Macros and defines used in specifying an ioctl | |
| 39 | .I request | |
| 40 | are located in the file | |
| 41 | .IR <sys/ioctl.h> . | |
| 42 | .SH "RETURN VALUE | |
| 43 | If an error has occurred, a value of \-1 is returned and | |
| 44 | .I errno | |
| 45 | is set to indicate the error. | |
| 46 | .SH ERRORS | |
| 384b8076 | 47 | .I Ioctl |
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48 | will fail if one or more of the following are true: |
| 49 | .TP 15 | |
| 50 | [EBADF] | |
| 51 | \fID\fP is not a valid descriptor. | |
| 52 | .TP 15 | |
| 53 | [ENOTTY] | |
| 54 | \fID\fP is not associated with a character | |
| 55 | special device. | |
| 56 | .TP 15 | |
| 57 | [ENOTTY] | |
| 58 | The specified request does not apply to the kind | |
| 59 | of object which the descriptor \fId\fP references. | |
| 60 | .TP 15 | |
| 61 | [EINVAL] | |
| 62 | \fIRequest\fP or \fIargp\fP is not valid. | |
| 63 | .SH "SEE ALSO" | |
| 64 | execve(2), fcntl(2), mt(4), tty(4), intro(4N) |