waveOutUnprepareHeader function (mmeapi.h)

The waveOutUnprepareHeader function cleans up the preparation performed by the waveOutPrepareHeader function. This function must be called after the device driver is finished with a data block. You must call this function before freeing the buffer.

Syntax

MMRESULT waveOutUnprepareHeader(
  HWAVEOUT  hwo,
  LPWAVEHDR pwh,
  UINT      cbwh
);

Parameters

hwo

Handle to the waveform-audio output device.

pwh

Pointer to a WAVEHDR structure identifying the data block to be cleaned up.

cbwh

Size, in bytes, of the WAVEHDR structure.

Return value

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

Remarks

This function complements waveOutPrepareHeader. You must call this function before freeing the buffer. After passing a buffer to the device driver with the waveOutWrite function, you must wait until the driver is finished with the buffer before calling waveOutUnprepareHeader.

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

Requirements

See also

Waveform Audio

Waveform Functions