waveOutUnprepareHeader (Compact 2013)
3/26/2014
This function cleans up the preparation performed by waveOutPrepareHeader. The function must be called after the device driver is finished with a data block. You must call this function before freeing the data 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
One of the values described in the following table is returned.
Value |
Description |
|---|---|
MMSYSERR_NOERROR |
Success. |
MMSYSERR_INVALHANDLE |
Specified device handle is invalid. |
MMSYSERR_NODRIVER |
No device driver is present. |
MMSYSERR_NOMEM |
Unable to allocate or lock memory. |
WAVERR_STILLPLAYING |
Data block pointed to by the pwh parameter is still in the queue. |
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
Header |
mmsystem.h |
Library |
coredll.lib |