MM_MOM_POSITIONCB message

The MM_MOM_POSITIONCB message is sent to a window when an MEVT_F_CALLBACK event is reached in the MIDI output stream.

MM_MOM_POSITIONCB 
wParam = (WPARAM) lpMidiHdr 
lParam = reserved 

Parameters

lpMidiHdr

Pointer to a MIDIHDR structure that identifies the event that caused the callback. The dwOffset member gives the offset of the event.

lParam

Reserved; do not use.

Return Value

This message does not return a value.

Remarks

Playback of the stream buffer continues even while the callback function is executing. Any events after the MEVT_F_CALLBACK event in the buffer will be scheduled and sent on time regardless of how much time is spent in the callback function.

If position callbacks are being generated more quickly than your application can process them, the dwOffset member of the MIDIHDR structure might refer to an event your application has not yet processed.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Mmsystem.h (include Windows.h)

See also

MIDI Messages