Manual page for IOCTL(2)
ioctl - control device
SYNOPSIS
#include <libc.h>
ioctl(d, request, argp)
int d;
unsigned long request;
char *argp;
DESCRIPTION
Ioctl
performs a variety of functions
on open descriptors. In particular, many operating
characteristics of character special files (e.g. terminals)
may be controlled with
ioctl
requests.
The writeups of various devices in section 4 discuss how
ioctl
applies to them.
An ioctl
request
has encoded in it whether the argument is an ``in'' parameter
or ``out'' parameter, and the size of the argument argp in bytes.
Macros and defines used in specifying an ioctl
request
are located in the file
<sys/ioctl.h>.
RETURN VALUE
If an error has occurred, a value of -1 is returned and
errno
is set to indicate the error.
ERRORS
Ioctl
will fail if one or more of the following are true:
- [EBADF]
-
D is not a valid descriptor.
- [ENOTTY]
-
D is not associated with a character
special device.
- [ENOTTY]
-
The specified request does not apply to the kind
of object that the descriptor d references.
- [EINVAL]
-
Request or argp is not valid.
SEE ALSO
execve(2), fcntl(2), mt(1), tty(4), intro(4N)
Created by unroff & hp-tools.
© somebody (See intro for details). All Rights Reserved.
Last modified 11/5/97
