MidiMIDI_OutUnprepareHeader Method

public static MIDIError MIDI_OutUnprepareHeader(
	IntPtr handle,
	IntPtr headerPtr
)

Public Shared Function MIDI_OutUnprepareHeader ( 
	handle As IntPtr,
	headerPtr As IntPtr
) As MIDIError

Parameters

handle

Type: SystemIntPtr
Handle to the MIDI output device.

headerPtr

Type: SystemIntPtr
Pointer to a MIDI_HEADER structure identifying the buffer to be cleaned up.

Return Value

This function is complementary to the MIDI_OutPrepareHeader(IntPtr, IntPtr) function. You must call MIDI_OutUnprepareHeader(IntPtr, IntPtr) before freeing the buffer. After passing a buffer to the device driver with the MIDI_OutLongMsg(IntPtr, IntPtr) function, you must wait until the device driver is finished with the buffer before calling MIDI_OutUnprepareHeader(IntPtr, IntPtr).

Unpreparing a buffer that has not been prepared has no effect, and the function returns 0.

For convenience the Prepare(Boolean, IntPtr) might also be used, which calls MIDI_InPrepareHeader(IntPtr, IntPtr) internally and provides the prepared header pointer in it's HeaderPtr member. In order to convert an IntPtr (e.g. as given in the MIDIINPROC with the MIM_LONGDATA or MIM_LONGERROR as param1) back to a MIDI_HEADER structure use the appropriate constructor overload of the MIDI_HEADER class taking a headerPtr.

Reference