Documentation/userspace-api/media/v4l/vidioc-subscribe-event.rst

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

File Facts

System: Linux kernel
Corpus path: Documentation/userspace-api/media/v4l/vidioc-subscribe-event.rst
Extension: .rst
Size: 3326 bytes
Lines: 114
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.

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

No C-style include directives detected by the generator.

Detected Declarations

No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

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

.. _VIDIOC_SUBSCRIBE_EVENT:
.. _VIDIOC_UNSUBSCRIBE_EVENT:

******************************************************
ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT
******************************************************

Name
====

VIDIOC_SUBSCRIBE_EVENT - VIDIOC_UNSUBSCRIBE_EVENT - Subscribe or unsubscribe event

Synopsis
========

.. c:macro:: VIDIOC_SUBSCRIBE_EVENT

``int ioctl(int fd, VIDIOC_SUBSCRIBE_EVENT, struct v4l2_event_subscription *argp)``

.. c:macro:: VIDIOC_UNSUBSCRIBE_EVENT

``int ioctl(int fd, VIDIOC_UNSUBSCRIBE_EVENT, struct v4l2_event_subscription *argp)``

Arguments
=========

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

``argp``
    Pointer to struct :c:type:`v4l2_event_subscription`.

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

Subscribe or unsubscribe V4L2 event. Subscribed events are dequeued by
using the :ref:`VIDIOC_DQEVENT` ioctl.

.. tabularcolumns:: |p{2.6cm}|p{4.4cm}|p{10.3cm}|

.. c:type:: v4l2_event_subscription

.. flat-table:: struct v4l2_event_subscription
    :header-rows:  0
    :stub-columns: 0
    :widths:       1 1 2

    * - __u32
      - ``type``
      - Type of the event, see :ref:`event-type`.

	.. note::

	   ``V4L2_EVENT_ALL`` can be used with
	   :ref:`VIDIOC_UNSUBSCRIBE_EVENT <VIDIOC_SUBSCRIBE_EVENT>` for
	   unsubscribing all events at once.
    * - __u32
      - ``id``
      - ID of the event source. If there is no ID associated with the
	event source, then set this to 0. Whether or not an event needs an
	ID depends on the event type.
    * - __u32
      - ``flags``
      - Event flags, see :ref:`event-flags`.
    * - __u32
      - ``reserved``\ [5]
      - Reserved for future extensions. Drivers and applications must set

Annotation

Atlas domain: Support Tooling And Documentation / Documentation.
Implementation status: atlas-only.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.