162306a36Sopenharmony_ci.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 262306a36Sopenharmony_ci.. c:namespace:: V4L 362306a36Sopenharmony_ci 462306a36Sopenharmony_ci.. _VIDIOC_ENUMAUDIO: 562306a36Sopenharmony_ci 662306a36Sopenharmony_ci********************** 762306a36Sopenharmony_ciioctl VIDIOC_ENUMAUDIO 862306a36Sopenharmony_ci********************** 962306a36Sopenharmony_ci 1062306a36Sopenharmony_ciName 1162306a36Sopenharmony_ci==== 1262306a36Sopenharmony_ci 1362306a36Sopenharmony_ciVIDIOC_ENUMAUDIO - Enumerate audio inputs 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ciSynopsis 1662306a36Sopenharmony_ci======== 1762306a36Sopenharmony_ci 1862306a36Sopenharmony_ci.. c:macro:: VIDIOC_ENUMAUDIO 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ci``int ioctl(int fd, VIDIOC_ENUMAUDIO, struct v4l2_audio *argp)`` 2162306a36Sopenharmony_ci 2262306a36Sopenharmony_ciArguments 2362306a36Sopenharmony_ci========= 2462306a36Sopenharmony_ci 2562306a36Sopenharmony_ci``fd`` 2662306a36Sopenharmony_ci File descriptor returned by :c:func:`open()`. 2762306a36Sopenharmony_ci 2862306a36Sopenharmony_ci``argp`` 2962306a36Sopenharmony_ci Pointer to struct :c:type:`v4l2_audio`. 3062306a36Sopenharmony_ci 3162306a36Sopenharmony_ciDescription 3262306a36Sopenharmony_ci=========== 3362306a36Sopenharmony_ci 3462306a36Sopenharmony_ciTo query the attributes of an audio input applications initialize the 3562306a36Sopenharmony_ci``index`` field and zero out the ``reserved`` array of a struct 3662306a36Sopenharmony_ci:c:type:`v4l2_audio` and call the :ref:`VIDIOC_ENUMAUDIO` 3762306a36Sopenharmony_ciioctl with a pointer to this structure. Drivers fill the rest of the 3862306a36Sopenharmony_cistructure or return an ``EINVAL`` error code when the index is out of 3962306a36Sopenharmony_cibounds. To enumerate all audio inputs applications shall begin at index 4062306a36Sopenharmony_cizero, incrementing by one until the driver returns ``EINVAL``. 4162306a36Sopenharmony_ci 4262306a36Sopenharmony_ciSee :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct 4362306a36Sopenharmony_ci:c:type:`v4l2_audio`. 4462306a36Sopenharmony_ci 4562306a36Sopenharmony_ciReturn Value 4662306a36Sopenharmony_ci============ 4762306a36Sopenharmony_ci 4862306a36Sopenharmony_ciOn success 0 is returned, on error -1 and the ``errno`` variable is set 4962306a36Sopenharmony_ciappropriately. The generic error codes are described at the 5062306a36Sopenharmony_ci:ref:`Generic Error Codes <gen-errors>` chapter. 5162306a36Sopenharmony_ci 5262306a36Sopenharmony_ciEINVAL 5362306a36Sopenharmony_ci The number of the audio input is out of bounds. 54