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The midiInUnprepareHeader function cleans up the preparation performed by the midiInPrepareHeader function.
MMRESULT midiInUnprepareHeader(
HMIDIIN hMidiIn,
LPMIDIHDR lpMidiInHdr,
UINT cbMidiInHdr
);
Parameters
hMidiIn
Handle to the MIDI input device.
lpMidiInHdr
Pointer to 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.
| Value | Description |
| 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.
Requirements
** Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
** Windows 95/98/Me:** Included in Windows 95 and later.
** Header:** Declared in Mmsystem.h; include Windows.h.
** Library:** Use Winmm.lib.
See Also
Musical Instrument Digital Interface (MIDI), MIDI Functions, midiInPrepareHeader, MIDIHDR, midiInAddBuffer