Set the data path of the recorder. This is to be used for multi file mode only, in single file mode you will provide the file and directory. See also GetDataPath(). The Recorder can't be in recording mode while changing the data path. You have to stop recording first. To determine if the Recorder is in recording mode use IsRecording(), to stop the Recorder from recording use StopRecording(). The changes to the prefix are made permanent by writing them to the gseos.ini configuration file. On the next invocation of GSEOS you will have the prefix preserved.