hpux man page for ioctl

ioctl(2)							System Calls Manual							  ioctl(2)

NAME
       ioctl - control device

SYNOPSIS
   Remarks
       The ANSI C "" construct denotes a variable length argument list whose optional [or required] members are given in the associated comment

DESCRIPTION
       performs a variety of functions on character special files (devices), or regular files and directories on VxFS file systems.  The write-ups
       of various devices in Section(7) discuss how applies to them.  The type of arg is dependent on the specific call, as described in  Section(7).

       request	is  made up of several fields which encode the size and direction of the argument (referenced by arg), as well as the desired com-
       mand.  An enumeration of the request fields are:

	      Argument is read by the driver
				  (meaning that the argument is copied from the application to the driver).

	      Argument is written by the driver
				  (meaning that the argument is copied from the driver to the application).  Ignored if an error occurs.

	      Number of bytes in the passed argument.
				  A nonzero size indicates that arg is a pointer to the passed argument.  A zero size indicates that  arg  is  the
				  passed argument (if the driver wants to use it), and is not treated as a pointer.

	      The request command itself.

       When both and are zero, it can be assumed that request is not encoded for size and direction, for compatibility purposes.  Requests that do
       not require any data to be passed and requests that use arg as a value (as opposed to a pointer), have the bit set to one and the field set
       to zero.

       The  following  macros  are  used  to  create  the request argument.  x and y are concatenated to form and shifted into the proper location
       according to is the type (e.g.  of the actual argument that the request references, and its size is taken and shifted into the  appropriate
       place according to

	      Sets		  and initializes the values at and accordingly.

	      Sets		  and initializes the values at and accordingly.

	      Sets both 	  and and initializes the values at and

       Note: any data structure referenced by arg must contain any pointers.

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

       fails if one or more of the following are true: IOC_OUT is ignored if an error occurs.

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

	      [ENOTTY]	     The request is not appropriate to the selected device.

	      [EINVAL]	     request or arg is not valid.

	      [EINTR]	     A signal was caught during the system call.

	      [EPERM]	     Typically	this  error  indicates	that  an  ioctl request was attempted that is forbidden in some way to the calling
			     process.

AUTHOR
       was developed by AT&T and HP.

SEE ALSO
       ioctl(5), privileges(5), arp(7P), socket(7), termio(7).

STANDARDS CONFORMANCE
																	  ioctl(2)