BOOL WINAPI mciSetDriverData(UINT uDeviceID, DWORD dwData)
This function sets the instance data associated with an MCI device.
uDeviceID
Specifies the MCI device ID.
dwData
Specifies the driver data to set.
Typically device drivers set the data when it is opened. The device driver will then retrieve the data with mciGetDriverData in response to subsequent messages.