NAME

ioctl − control device

SYNOPSIS

#include <sys/ioctl.h>

ioctl(fildes, request, arg)

DESCRIPTION

Ioctl performs a variety of functions on character special files (devices).  The writeups of various devices in Section 4 discuss how ioctl applies to them. 

Ioctl will fail if one or more of the following are true:

Fildes is not a valid open file descriptor.  ­[EBADF]

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

Request or arg is not valid.  See tty(4). ­[EINVAL]

RETURN VALUE

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

SEE ALSO

tty(4). 

May 16, 1980