HRESULT Stop();
Causes the sound buffer to stop playing.
·Returns DS_OK if successful, or one of the following error values otherwise:
DSERR_INVALIDPARAM DSERR_PRIOLEVELNEEDED
For secondary buffers, IDirectSoundBuffer::Stop will set the current position of the buffer to the sample that follows the last sample played. This means that if the IDirectSoundBuffer::Play method is called on the buffer, it will continue playing where it left off.
For primary buffers, if an application has the DSSCL_WRITEPRIMARY level, this method will stop the buffer and reset the current position to 0 (the beginning of the buffer). This is necessary because the primary buffers on most sound cards can only play from the beginning of the buffer.
However, if IDirectSoundBuffer::Stop is called on a primary buffer and the application has a cooperative level other than DSSCL_WRITEPRIMARY, this method simply reverses the effects of IDirectSoundBuffer::Play. It configures the primary buffer to stop if no secondary buffers are playing. If other buffers are playing in this or other applications, the primary buffer will not actually stop until they are stopped. This method is useful because playing the primary buffer consumes processing overhead even if the buffer is playing sound data with the amplitude of 0 dB.