This function defines a time period for a point. It returns a point period ID which is used by the EOS_PT_EXTRACTPERIOD function to read the fields from a level for those records within the time period. The point structure must have a level with the Time field defined. 
            Examples
            In this example, we define a time period with a start time of 35208757.6 and a stop time of 35984639.2:
            starttime = 35208757.6d
            stoptime = 35984639.2d
            periodID = EOS_PT_DEFTIMEPERIOD(pointID, starttime, stoptime)
            Syntax
            Result = EOS_PT_DEFTIMEPERIOD(pointID, starttime, stoptime)
            Return Value
            Returns the point periodID if successful and FAIL (–1) otherwise.
            Arguments
            pointID
            Point id (long) returned by EOS_PT_CREATE or EOS_PT_ATTACH.
            starttime
            Start time (double) of period.
            stoptime
            Stop time (double) of period.
            Keywords
            None
            Version History