.. -*- coding: utf-8; mode: rst -*-
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.. _VIDIOC_ENUMINPUT:
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**********************
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ioctl VIDIOC_ENUMINPUT
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**********************
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Name
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====
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VIDIOC_ENUMINPUT - Enumerate video inputs
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Synopsis
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========
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.. c:function:: int ioctl( int fd, VIDIOC_ENUMINPUT, struct v4l2_input *argp )
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:name: VIDIOC_ENUMINPUT
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <func-open>`.
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``argp``
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Pointer to struct :c:type:`v4l2_input`.
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Description
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===========
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To query the attributes of a video input applications initialize the
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``index`` field of struct :c:type:`v4l2_input` and call the
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:ref:`VIDIOC_ENUMINPUT` with a pointer to this structure. Drivers
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fill the rest of the structure or return an ``EINVAL`` error code when the
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index is out of bounds. To enumerate all inputs applications shall begin
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at index zero, incrementing by one until the driver returns ``EINVAL``.
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.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
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.. c:type:: v4l2_input
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.. flat-table:: struct v4l2_input
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 1 2
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* - __u32
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- ``index``
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- Identifies the input, set by the application.
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* - __u8
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- ``name``\ [32]
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- Name of the video input, a NUL-terminated ASCII string, for
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example: "Vin (Composite 2)". This information is intended for the
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user, preferably the connector label on the device itself.
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* - __u32
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- ``type``
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- Type of the input, see :ref:`input-type`.
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* - __u32
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- ``audioset``
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- Drivers can enumerate up to 32 video and audio inputs. This field
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shows which audio inputs were selectable as audio source if this
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was the currently selected video input. It is a bit mask. The LSB
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corresponds to audio input 0, the MSB to input 31. Any number of
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bits can be set, or none.
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When the driver does not enumerate audio inputs no bits must be
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set. Applications shall not interpret this as lack of audio
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support. Some drivers automatically select audio sources and do
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not enumerate them since there is no choice anyway.
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For details on audio inputs and how to select the current input
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see :ref:`audio`.
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* - __u32
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- ``tuner``
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- Capture devices can have zero or more tuners (RF demodulators).
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When the ``type`` is set to ``V4L2_INPUT_TYPE_TUNER`` this is an
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RF connector and this field identifies the tuner. It corresponds
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to struct :c:type:`v4l2_tuner` field ``index``. For
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details on tuners see :ref:`tuner`.
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* - :ref:`v4l2_std_id <v4l2-std-id>`
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- ``std``
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- Every video input supports one or more different video standards.
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This field is a set of all supported standards. For details on
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video standards and how to switch see :ref:`standard`.
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* - __u32
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- ``status``
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- This field provides status information about the input. See
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:ref:`input-status` for flags. With the exception of the sensor
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orientation bits ``status`` is only valid when this is the current
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input.
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* - __u32
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- ``capabilities``
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- This field provides capabilities for the input. See
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:ref:`input-capabilities` for flags.
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* - __u32
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- ``reserved``\ [3]
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- Reserved for future extensions. Drivers must set the array to
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zero.
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.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
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.. _input-type:
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.. flat-table:: Input Types
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:header-rows: 0
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:stub-columns: 0
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:widths: 3 1 4
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* - ``V4L2_INPUT_TYPE_TUNER``
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- 1
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- This input uses a tuner (RF demodulator).
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* - ``V4L2_INPUT_TYPE_CAMERA``
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- 2
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- Any non-tuner video input, for example Composite Video,
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S-Video, HDMI, camera sensor. The naming as ``_TYPE_CAMERA`` is historical,
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today we would have called it ``_TYPE_VIDEO``.
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* - ``V4L2_INPUT_TYPE_TOUCH``
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- 3
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- This input is a touch device for capturing raw touch data.
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.. tabularcolumns:: |p{4.8cm}|p{2.6cm}|p{10.1cm}|
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.. _input-status:
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.. flat-table:: Input Status Flags
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:header-rows: 0
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:stub-columns: 0
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* - :cspan:`2` General
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* - ``V4L2_IN_ST_NO_POWER``
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- 0x00000001
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- Attached device is off.
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* - ``V4L2_IN_ST_NO_SIGNAL``
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- 0x00000002
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-
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* - ``V4L2_IN_ST_NO_COLOR``
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- 0x00000004
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- The hardware supports color decoding, but does not detect color
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modulation in the signal.
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* - :cspan:`2` Sensor Orientation
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* - ``V4L2_IN_ST_HFLIP``
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- 0x00000010
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- The input is connected to a device that produces a signal that is
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flipped horizontally and does not correct this before passing the
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signal to userspace.
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* - ``V4L2_IN_ST_VFLIP``
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- 0x00000020
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- The input is connected to a device that produces a signal that is
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flipped vertically and does not correct this before passing the
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signal to userspace.
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.. note:: A 180 degree rotation is the same as HFLIP | VFLIP
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* - :cspan:`2` Analog Video
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* - ``V4L2_IN_ST_NO_H_LOCK``
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- 0x00000100
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- No horizontal sync lock.
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* - ``V4L2_IN_ST_COLOR_KILL``
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- 0x00000200
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- A color killer circuit automatically disables color decoding when
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it detects no color modulation. When this flag is set the color
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killer is enabled *and* has shut off color decoding.
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* - ``V4L2_IN_ST_NO_V_LOCK``
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- 0x00000400
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- No vertical sync lock.
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* - ``V4L2_IN_ST_NO_STD_LOCK``
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- 0x00000800
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- No standard format lock in case of auto-detection format
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by the component.
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* - :cspan:`2` Digital Video
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* - ``V4L2_IN_ST_NO_SYNC``
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- 0x00010000
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- No synchronization lock.
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* - ``V4L2_IN_ST_NO_EQU``
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- 0x00020000
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- No equalizer lock.
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* - ``V4L2_IN_ST_NO_CARRIER``
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- 0x00040000
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- Carrier recovery failed.
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* - :cspan:`2` VCR and Set-Top Box
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* - ``V4L2_IN_ST_MACROVISION``
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- 0x01000000
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- Macrovision is an analog copy prevention system mangling the video
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signal to confuse video recorders. When this flag is set
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Macrovision has been detected.
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* - ``V4L2_IN_ST_NO_ACCESS``
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- 0x02000000
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- Conditional access denied.
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* - ``V4L2_IN_ST_VTR``
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- 0x04000000
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- VTR time constant. [?]
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.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
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.. _input-capabilities:
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.. flat-table:: Input capabilities
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:header-rows: 0
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:stub-columns: 0
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:widths: 3 1 4
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* - ``V4L2_IN_CAP_DV_TIMINGS``
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- 0x00000002
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- This input supports setting video timings by using
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``VIDIOC_S_DV_TIMINGS``.
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* - ``V4L2_IN_CAP_STD``
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- 0x00000004
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- This input supports setting the TV standard by using
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``VIDIOC_S_STD``.
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* - ``V4L2_IN_CAP_NATIVE_SIZE``
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- 0x00000008
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- This input supports setting the native size using the
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``V4L2_SEL_TGT_NATIVE_SIZE`` selection target, see
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:ref:`v4l2-selections-common`.
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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EINVAL
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The struct :c:type:`v4l2_input` ``index`` is out of
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bounds.
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