midiInUnprepareHeader

The midiInUnprepareHeader function cleans up the preparation performed by the midiInPrepareHeader function.

MMRESULT midiInUnprepareHeader(

HMIDIIN hMidiIn,
LPMIDIHDR lpMidiInHdr,
UINT cbMidiInHdr
);

Parameters

hMidiIn

Handle of the MIDI input device.

lpMidiInHdr

Address of a MIDIHDR structure identifying the buffer to be cleaned up.

cbMidiInHdr

Size of the MIDIHDR structure.

Return Values

Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following:

MIDIERR_STILLPLAYING	The buffer pointed to by lpMidiInHdr is still in the queue.
MMSYSERR_INVALPARAM	The specified pointer or structure is invalid.
MMSYSERR_INVALHANDLE	The specified device handle is invalid.

Remarks

This function is complementary to midiInPrepareHeader. You must use this function before freeing the buffer. After passing a buffer to the device driver by using the midiInAddBuffer function, you must wait until the driver is finished with the buffer before using midiInUnprepareHeader. Unpreparing a buffer that has not been prepared has no effect, and the function returns MMSYSERR_NOERROR.

See Also

midiInPrepareHeader, MIDIHDR, midiInAddBuffer

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