| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _VIDIOC_ENUMAUDIO: |
| |
| ********************** |
| ioctl VIDIOC_ENUMAUDIO |
| ********************** |
| |
| Name |
| ==== |
| |
| VIDIOC_ENUMAUDIO - Enumerate audio inputs |
| |
| |
| Synopsis |
| ======== |
| |
| .. c:function:: int ioctl( int fd, int request, struct v4l2_audio *argp ) |
| |
| |
| Arguments |
| ========= |
| |
| ``fd`` |
| File descriptor returned by :ref:`open() <func-open>`. |
| |
| ``request`` |
| VIDIOC_ENUMAUDIO |
| |
| ``argp`` |
| |
| |
| Description |
| =========== |
| |
| To query the attributes of an audio input applications initialize the |
| ``index`` field and zero out the ``reserved`` array of a struct |
| :ref:`v4l2_audio <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 |
| :ref:`v4l2_audio <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. |