lifetime of the MIDI/MIXER/WAVEOPENDESC structure?

Hi,

MSDN is silent about the lifetime of the MIDI/MIXER/WAVEOPENDESC structure
that is deliverred via the W/MODM_OPEN/MXM_OPEN message to the winmm drivers
(WAVEOOPENDESC is not even documented for MS-Windows (not CE) anymore).

http://msdn.microsoft.com/en-us/library/ff537518%28v=vs.85%29.aspx MIDIOPENDESC

IMHO, it would make a lot of sense if the structure remained allocated
for the whole lifetime of the open/close cycle, so the driver need not make a copy of it.

Is there anybody who knows more about this topic?

Thank you,
 Jörg Höhle