WIDM_GETNUMDEVS

This message is used in an MMDRV_MESSAGE_PARAMS structure passed to the WAV_IOControl function to request a waveform input driver to return the number of device instances that it supports.

Parameters

uDeviceId

Device identifier—0, 1, 2, and so on—for the target device.

uMsg

Specifies this message.

dwUser

Specifies a device instance identifier.

dwParam1

Not used.

dwParam2

Not used.

Return Values

The driver returns the number of waveform input device instances it supports. The default audio driver's MDD layer returns 1.

Remarks

The ACM sends this message by calling the audio driver’s WAV_IOControl entry point through the DeviceIoControl function.