See also WODM_PREPARE
Sent to a waveform output device to clean up the preparation performed by the WODM_PREPARE message. If a driver supports this message, then it must also support WODM_PREPARE.
MMSYSERR_NOTENABLED | The driver failed to load or initialize. |
WAVERR_STILLPLAYING | The specified data block is still in the output queue. |
DWORD dwParam1
Specifies a far pointer to WAVEHDR structure identifying the data block.
DWORD dwParam2
Specifies the size of the WAVEHDR structure.
Driver support for this message is optional. If a driver supports the WODM_PREPARE message, then it must also support WODM_UNPREPARE.
The default response for this message is to return MMSYSERR_NOTSUPPORTED. In this case, MMSYSTEM will clean up the preparation previously done on the memory block. If a driver performs the preparation itself, it must clean up the preparation and reset the WHDR_PREPARED flag in the dwFlags field of the WAVEHDR structure. If a data block has not been prepared, MMSYSERR_NOERROR should be returned.