This message is sent to a waveform output device driver to request the current playback rate setting for a device.
DWORD dwParam1
Specifies a far pointer to a DWORD location. The driver fills this location with the current playback rate setting. The rate is specified as a fixed-point value. The high-order word of the DWORD contains the signed integer part of the number, and the low-order word contains the fractional part. The fraction is expressed as a WORD in which a value of 0x8000 represents one half, and 0x4000 represents one quarter. For example, the value 0x00010000 specifies a multiplier of 1.0 (no playback rate change), and a value of 0x000F8000 specifies a multiplier of 15.5.
DWORD dwParam2
Unused.
The return value is an error code, or zero (MMSYSERR_NOERROR) if the operation is successful. Possible error codes are:
MMSYSERR_NOTENABLED
The driver failed to load or initialize.
MMSYSERR_NOTSUPPORTED
The driver does not support changes to the pitch rate.
Driver support for playback rate changes is optional. However, if a driver supports changes to the playback rate with the WODM_SETPLAYBACKRATE message, it must support queries with the WODM_GETPLAYBACKRATE message.