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WIDM_GETNUMDEVS (Compact 2013)

  • Article

3/26/2014

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.

Requirements

Header

mmddk.h

See Also

Reference

Waveform Input Driver Messages
MMDRV_MESSAGE_PARAMS
WAV_IOControl