ioctl(2) [opendarwin man page]

IOCTL(2)						      BSD System Calls Manual							  IOCTL(2)

NAME

     ioctl -- control device

SYNOPSIS

     #include <sys/ioctl.h>

     int
     ioctl(int d, unsigned long request, char *argp);

DESCRIPTION

     The ioctl() function manipulates the underlying device parameters of special files.  In particular, many operating characteristics of charac-
     ter special files (e.g. terminals) may be controlled with ioctl() requests.  The argument d must be an open file descriptor.

     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 VALUES

     If an error has occurred, a value of -1 is returned and errno is set to indicate the error.

ERRORS

     Ioctl() will fail if:

     [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

     mt(1), cdio(1), chio(1), execve(2), fcntl(2), tty(4), intro(4)

HISTORY

     An ioctl() function call appeared in Version 7 AT&T UNIX.

4th Berkeley Distribution					 December 11, 1993					 4th Berkeley Distribution

ioctl(2)							System Calls Manual							  ioctl(2)

Name
       ioctl - control device

Syntax
       #include <sys/ioctl.h>

       ioctl(d, request, argp)
       int d, request;
       char *argp;

Description
       The  call  performs  a  variety of functions on open descriptors.  In particular, many operating characteristics of character special files
       (for example, terminals) can be controlled with requests.  Certain requests operate on a number of device  types.  These  include  informa-
       tional  requests,  such	as and The descriptions of various devices in the Reference Pages, Section 4: Special Files discuss how applies to
       them. Also consult <sys/ioctl.h> for more information.

       An 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 request are located in the file <sys/ioctl.h>.

Return Values
       If an error has occurred, a value of -1 is returned, and errno is set to indicate the error.

Diagnostics
       The call fails under the following conditions:

       [EBADF]	      The d is not a valid descriptor.

       [ENOTTY]       The d is not associated with a character special device.

       [ENOTTY]       The specified request does not apply to the kind of object which the descriptor d references.

       [EINVAL]       The request or argp is not valid.

       [EFAULT]       The argp points to memory that is not part of the process' address space.

See Also
       execve(2), fcntl(2), devio(4), intro(4n), mu(4), nbuf(4), tty(4)

																	  ioctl(2)