7.12. ioctl VIDIOC_ENUMAUDOUT

7.12.1. Name

VIDIOC_ENUMAUDOUT - Enumerate audio outputs

7.12.2. Synopsis

int ioctl(int fd, VIDIOC_ENUMAUDOUT, struct v4l2_audioout *argp)

7.12.3. Arguments

fd

File descriptor returned by open().

argp

Pointer to struct v4l2_audioout.

7.12.4. Description

To query the attributes of an audio output applications initialize the index field and zero out the reserved array of a struct v4l2_audioout and call the VIDIOC_G_AUDOUT 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 outputs applications shall begin at index zero, incrementing by one until the driver returns EINVAL.

注釈

Connectors on a TV card to loop back the received audio signal to a sound card are not audio outputs in this sense.

See VIDIOC_G_AUDIOout for a description of struct v4l2_audioout.

7.12.5. 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 Generic Error Codes chapter.

EINVAL

The number of the audio output is out of bounds.