midiOutUnprepareHeader
The midiOutUnprepareHeader
function cleans up the preparation performed by the midiOutPrepareHeader function.
MMRESULT midiOutUnprepareHeader(
|
HMIDIOUT hmo, |
|
|
LPMIDIHDR lpMidiOutHdr, |
|
|
UINT cbMidiOutHdr |
|
|
); |
|
Parameters
hmo
Handle of the
MIDI output device. This parameter can also be the handle of a MIDI stream cast
to HMIDIOUT.
lpMidiOutHdr
Address of a MIDIHDR structure identifying the
buffer to be cleaned up.
cbMidiOutHdr
Size, in
bytes, 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 lpMidiOutHdr is still in the queue. |
|
MMSYSERR_INVALHANDLE |
The
specified device handle is invalid. |
|
MMSYSERR_INVALPARAM |
The
specified pointer or structure is invalid. |
Remarks
This function
is complementary to the midiOutPrepareHeader function. You must call midiOutUnprepareHeader
before freeing the buffer. After passing a buffer to the device driver with the
midiOutLongMsg function, you must wait until the device driver is
finished with the buffer before calling midiOutUnprepareHeader.
Unpreparing a
buffer that has not been prepared has no effect, and the function returns
MMSYSERR_NOERROR.
See Also