After you have finished playing a waveform-audio file and deallocating the associated header files, call the waveOutClose or waveInClose function to close the output device. If you call these functions while an application is still using a waveform-audio file, the close operation fails and the function returns an error value indicating that the device is not closed. If you do not want to wait for recording or playback to end before closing the device, call the waveOutReset or waveInReset function.