Documentation/userspace-api/media/v4l/vidioc-enuminput.rst

Source file repositories/reference/linux-study-clean/Documentation/userspace-api/media/v4l/vidioc-enuminput.rst

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Linux kernel
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Documentation/userspace-api/media/v4l/vidioc-enuminput.rst
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.rst
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Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Annotated Snippet

.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: V4L

.. _VIDIOC_ENUMINPUT:

**********************
ioctl VIDIOC_ENUMINPUT
**********************

Name
====

VIDIOC_ENUMINPUT - Enumerate video inputs

Synopsis
========

.. c:macro:: VIDIOC_ENUMINPUT

``int ioctl(int fd, VIDIOC_ENUMINPUT, struct v4l2_input *argp)``

Arguments
=========

``fd``
    File descriptor returned by :c:func:`open()`.

``argp``
    Pointer to struct :c:type:`v4l2_input`.

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

To query the attributes of a video input applications initialize the
``index`` field of struct :c:type:`v4l2_input` and call the
:ref:`VIDIOC_ENUMINPUT` with a pointer to this structure. Drivers
fill the rest of the structure or return an ``EINVAL`` error code when the
index is out of bounds. To enumerate all inputs applications shall begin
at index zero, incrementing by one until the driver returns ``EINVAL``.

.. tabularcolumns:: |p{3.0cm}|p{3.5cm}|p{10.8cm}|

.. c:type:: v4l2_input

.. flat-table:: struct v4l2_input
    :header-rows:  0
    :stub-columns: 0
    :widths:       1 1 2

    * - __u32
      - ``index``
      - Identifies the input, set by the application.
    * - __u8
      - ``name``\ [32]
      - Name of the video input, a NUL-terminated ASCII string, for
	example: "Vin (Composite 2)". This information is intended for the
	user, preferably the connector label on the device itself.
    * - __u32
      - ``type``
      - Type of the input, see :ref:`input-type`.
    * - __u32
      - ``audioset``
      - Drivers can enumerate up to 32 video and audio inputs. This field
	shows which audio inputs were selectable as audio source if this
	was the currently selected video input. It is a bit mask. The LSB
	corresponds to audio input 0, the MSB to input 31. Any number of
	bits can be set, or none.

	When the driver does not enumerate audio inputs no bits must be
	set. Applications shall not interpret this as lack of audio

Annotation

Implementation Notes