Documentation/userspace-api/media/v4l/vidioc-enumaudio.rst
Source file repositories/reference/linux-study-clean/Documentation/userspace-api/media/v4l/vidioc-enumaudio.rst
File Facts
- System
- Linux kernel
- Corpus path
Documentation/userspace-api/media/v4l/vidioc-enumaudio.rst- Extension
.rst- Size
- 1332 bytes
- Lines
- 54
- 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_ENUMAUDIO:
**********************
ioctl VIDIOC_ENUMAUDIO
**********************
Name
====
VIDIOC_ENUMAUDIO - Enumerate audio inputs
Synopsis
========
.. c:macro:: VIDIOC_ENUMAUDIO
``int ioctl(int fd, VIDIOC_ENUMAUDIO, struct v4l2_audio *argp)``
Arguments
=========
``fd``
File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`v4l2_audio`.
Description
===========
To query the attributes of an audio input applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
:c:type:`v4l2_audio` and call the :ref:`VIDIOC_ENUMAUDIO`
ioctl 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 audio inputs applications shall begin at index
zero, incrementing by one until the driver returns ``EINVAL``.
See :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct
:c:type:`v4l2_audio`.
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 audio input is out of bounds.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.