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

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

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Linux kernel
Corpus path
Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
Extension
.rst
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11756 bytes
Lines
378
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Detected Declarations

Annotated Snippet

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

.. _VIDIOC_DQEVENT:

********************
ioctl VIDIOC_DQEVENT
********************

Name
====

VIDIOC_DQEVENT - Dequeue event

Synopsis
========

.. c:macro:: VIDIOC_DQEVENT

``int ioctl(int fd, VIDIOC_DQEVENT, struct v4l2_event *argp)``

Arguments
=========

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

``argp``
    Pointer to struct :c:type:`v4l2_event`.

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

Dequeue an event from a video device. No input is required for this
ioctl. All the fields of the struct :c:type:`v4l2_event`
structure are filled by the driver. The file handle will also receive
exceptions which the application may get by e.g. using the select system
call.

.. c:type:: v4l2_event

.. tabularcolumns:: |p{3.0cm}|p{3.4cm}|p{10.9cm}|


.. flat-table:: struct v4l2_event
    :header-rows:  0
    :stub-columns: 0
    :widths:       1 1 2

    * - __u32
      - ``type``
      - Type of the event, see :ref:`event-type`.
    * - union {
      - ``u``
    * - struct :c:type:`v4l2_event_vsync`
      - ``vsync``
      - Event data for event ``V4L2_EVENT_VSYNC``.
    * - struct :c:type:`v4l2_event_ctrl`
      - ``ctrl``
      - Event data for event ``V4L2_EVENT_CTRL``.
    * - struct :c:type:`v4l2_event_frame_sync`
      - ``frame_sync``
      - Event data for event ``V4L2_EVENT_FRAME_SYNC``.
    * - struct :c:type:`v4l2_event_motion_det`
      - ``motion_det``
      - Event data for event V4L2_EVENT_MOTION_DET.
    * - struct :c:type:`v4l2_event_src_change`
      - ``src_change``
      - Event data for event V4L2_EVENT_SOURCE_CHANGE.
    * - __u8

Annotation

Implementation Notes