midiOutUnprepareHeader function (mmeapi.h)

The midiOutUnprepareHeader function cleans up the preparation performed by the midiOutPrepareHeader function.

Syntax

MMRESULT midiOutUnprepareHeader(
  HMIDIOUT  hmo,
  LPMIDIHDR pmh,
  UINT      cbmh
);

Parameters

hmo

Handle to the MIDI output device. This parameter can also be the handle of a MIDI stream cast to HMIDIOUT.

pmh

Pointer to a MIDIHDR structure identifying the buffer to be cleaned up.

cbmh

Size, in bytes, of the MIDIHDR structure.

Return value

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

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.

Requirements

See also

Allocating and Preparing MIDI Data Blocks

MIDI Functions