[deliverable/linux.git] / Documentation / media / uapi / mediactl / media-func-ioctl.rst

.. -*- coding: utf-8; mode: rst -*-

.. _media-func-ioctl:

*************
media ioctl()
*************

Name
====

media-ioctl - Control a media device


Synopsis
========

.. code-block:: c

    #include <sys/ioctl.h>


.. c:function:: int ioctl( int fd, int request, void *argp )
    :name: mc-ioctl

Arguments
=========

``fd``
    File descriptor returned by :c:func:`open() <mc-open>`.

``request``
    Media ioctl request code as defined in the media.h header file, for
    example MEDIA_IOC_SETUP_LINK.

``argp``
    Pointer to a request-specific structure.


Description
===========

The :ref:`ioctl() <media-func-ioctl>` function manipulates media device
parameters. The argument ``fd`` must be an open file descriptor.

The ioctl ``request`` code specifies the media function to be called. It
has encoded in it whether the argument is an input, output or read/write
parameter, and the size of the argument ``argp`` in bytes.

Macros and structures definitions specifying media ioctl requests and
their parameters are located in the media.h header file. All media ioctl
requests, their respective function and parameters are specified in
:ref:`media-user-func`.


Return Value
============

On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.

Request-specific error codes are listed in the individual requests
descriptions.

When an ioctl that takes an output or read/write parameter fails, the
parameter remains unmodified.
Commit	Line	Data
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
	2
	3	.. _media-func-ioctl:
	4
	5	*************
	6	media ioctl()
	7	*************
	8
15e7d615	9	Name
586027ce	10	====
5377d91f	11
586027ce	12	media-ioctl - Control a media device
5377d91f	13
15e7d615 MCC	14
15e7d615 MCC	15	Synopsis
5377d91f MH	16	========
	17
	18	.. code-block:: c
	19
	20	#include <sys/ioctl.h>
	21
	22
1b81f010	23	.. c:function:: int ioctl( int fd, int request, void *argp )
5ccbb182	24	:name: mc-ioctl
586027ce	25
15e7d615	26	Arguments
5377d91f MH	27	=========
	28
	29	``fd``
5ccbb182	30	File descriptor returned by :c:func:`open() <mc-open>`.
5377d91f MH	31
	32	``request``
	33	Media ioctl request code as defined in the media.h header file, for
	34	example MEDIA_IOC_SETUP_LINK.
	35
	36	``argp``
	37	Pointer to a request-specific structure.
	38
	39
15e7d615	40	Description
5377d91f MH	41	===========
5377d91f MH	42
8c1cc62a MCC	43	The :ref:`ioctl() <media-func-ioctl>` function manipulates media device
8c1cc62a MCC	44	parameters. The argument ``fd`` must be an open file descriptor.
5377d91f MH	45
	46	The ioctl ``request`` code specifies the media function to be called. It
	47	has encoded in it whether the argument is an input, output or read/write
	48	parameter, and the size of the argument ``argp`` in bytes.
	49
	50	Macros and structures definitions specifying media ioctl requests and
	51	their parameters are located in the media.h header file. All media ioctl
	52	requests, their respective function and parameters are specified in
	53	:ref:`media-user-func`.
	54
	55
15e7d615	56	Return Value
5377d91f MH	57	============
	58
	59	On success 0 is returned, on error -1 and the ``errno`` variable is set
	60	appropriately. The generic error codes are described at the
	61	:ref:`Generic Error Codes <gen-errors>` chapter.
	62
	63	Request-specific error codes are listed in the individual requests
	64	descriptions.
	65
	66	When an ioctl that takes an output or read/write parameter fails, the
	67	parameter remains unmodified.