manpagez: man (manual) pages & more
man ioctl(2)
Home | html | info | man
ioctl(2)                    BSD System Calls Manual                   ioctl(2)


NAME

     ioctl -- control device


SYNOPSIS

     #include <sys/ioctl.h>

     int
     ioctl(int fildes, unsigned long request, ...);


DESCRIPTION

     The ioctl() function manipulates the underlying device parameters of spe-
     cial files.  In particular, many operating characteristics of character
     special files (e.g. terminals) may be controlled with ioctl() requests.
     The argument fildes 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]            fildes is not a valid descriptor.

     [EINVAL]           Request or argp is not valid.

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

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


SEE ALSO

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


HISTORY

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

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

Mac OS X 10.9.1 - Generated Mon Jan 6 08:01:01 CST 2014