waveOutPrepareHeader
The waveOutPrepareHeader
function prepares a waveform-audio data block for playback.
MMRESULT waveOutPrepareHeader(
|
HWAVEOUT hwo, |
|
|
LPWAVEHDR pwh, |
|
|
UINT cbwh |
|
|
); |
|
Parameters
hwo
Handle of the
waveform-audio output device.
pwh
Address of a WAVEHDR structure that identifies
the data block to be prepared.
cbwh
Size, in
bytes, of the WAVEHDR structure.
Return Values
Returns
MMSYSERR_NOERROR if successful or an error otherwise. Possible error values
include the following:
|
MMSYSERR_INVALHANDLE |
Specified
device handle is invalid. |
|
MMSYSERR_NODRIVER |
No device
driver is present. |
|
MMSYSERR_NOMEM |
Unable to
allocate or lock memory. |
Remarks
The lpData,
dwBufferLength, and dwFlags members of the WAVEHDR
structure must be set before calling this function (dwFlags must be
zero).
The dwFlags,
dwBufferLength, and dwLoops members of the WAVEHDR
structure can change between calls to this function and the waveOutWrite
function. (The only flags that can change in this interval for the dwFlags
member are WHDR_BEGINLOOP and WHDR_ENDLOOP.) If you change the size specified
by dwBufferLength before the call to waveOutWrite, the new value
must be less than the prepared value.
Preparing a
header that has already been prepared has no effect, and the function returns
zero.
See Also