[deliverable/linux.git] / Documentation / linux_tv / media / v4l / vidioc-g-input.rst

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

.. _VIDIOC_G_INPUT:

************************************
ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT
************************************

*man VIDIOC_G_INPUT(2)*

VIDIOC_S_INPUT
Query or select the current video input


Synopsis
========

.. c:function:: int ioctl( int fd, int request, int *argp )

Arguments
=========

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

``request``
    VIDIOC_G_INPUT, VIDIOC_S_INPUT

``argp``


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

To query the current video input applications call the
:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver
stores the number of the input, as in the struct
:ref:`v4l2_input <v4l2-input>` ``index`` field. This ioctl will fail
only when there are no video inputs, returning EINVAL.

To select a video input applications store the number of the desired
input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer
to this integer. Side effects are possible. For example inputs may
support different video standards, so the driver may implicitly switch
the current standard. Because of these possible side effects
applications must select an input before querying or negotiating any
other parameters.

Information about video inputs is available using the
:ref:`VIDIOC_ENUMINPUT` ioctl.


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.

EINVAL
    The number of the video input is out of bounds.


.. ------------------------------------------------------------------------------
.. This file was automatically converted from DocBook-XML with the dbxml
.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
.. from the linux kernel, refer to:
..
.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
.. ------------------------------------------------------------------------------
Commit	Line	Data
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
5377d91f MH	2
af4a4d0d	3	.. _VIDIOC_G_INPUT:
5377d91f MH	4
	5	************************************
	6	ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT
	7	************************************
	8
	9	man VIDIOC_G_INPUT(2)
	10
	11	VIDIOC_S_INPUT
	12	Query or select the current video input
	13
	14
	15	Synopsis
	16	========
	17
	18	.. c:function:: int ioctl( int fd, int request, int *argp )
	19
	20	Arguments
	21	=========
	22
	23	``fd``
	24	File descriptor returned by :ref:`open() <func-open>`.
	25
	26	``request``
	27	VIDIOC_G_INPUT, VIDIOC_S_INPUT
	28
	29	``argp``
	30
	31
	32	Description
	33	===========
	34
	35	To query the current video input applications call the
4e03cb76	36	:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver
5377d91f MH	37	stores the number of the input, as in the struct
	38	:ref:`v4l2_input <v4l2-input>` ``index`` field. This ioctl will fail
	39	only when there are no video inputs, returning EINVAL.
	40
	41	To select a video input applications store the number of the desired
2212ff25	42	input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer
5377d91f MH	43	to this integer. Side effects are possible. For example inputs may
	44	support different video standards, so the driver may implicitly switch
	45	the current standard. Because of these possible side effects
	46	applications must select an input before querying or negotiating any
	47	other parameters.
	48
	49	Information about video inputs is available using the
7347081e	50	:ref:`VIDIOC_ENUMINPUT` ioctl.
5377d91f MH	51
	52
	53	Return Value
	54	============
	55
	56	On success 0 is returned, on error -1 and the ``errno`` variable is set
	57	appropriately. The generic error codes are described at the
	58	:ref:`Generic Error Codes <gen-errors>` chapter.
	59
	60	EINVAL
	61	The number of the video input is out of bounds.
	62
	63
	64	.. ------------------------------------------------------------------------------
	65	.. This file was automatically converted from DocBook-XML with the dbxml
	66	.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
	67	.. from the linux kernel, refer to:
	68	..
	69	.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
	70	.. ------------------------------------------------------------------------------