Elapsed Time Example Involving Different Days

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   PROCEDURE elaptime
   PARAMETER m.startdate, m.enddate, m.starttime, m.endtime
   * pass startdate, an 8-character starttime (HH:MM:SS), an enddate,
   * and an 8-character endtime
   * perform parameter type checking: return value of -1 indicates
   * invalid parameter type
   * Example of using the function elaptime:
   * TempVariable=ElapTime({01/01/94},{01/02/94},"00:01:00",00:01:00")

   IF TYPE('m.startdate') # "D" .OR. ;
       TYPE('m.enddate') # "D" .OR. ;
       (TYPE('m.starttime') # "C" .AND. LEN(m.starttime) # 8) .OR. ;
       (TYPE('m.endtime') # "C" .AND. LEN(m.endtime) # 8)
       RETURN -1
   ENDIF

   * if startdate > enddate, or same date and starttime > endtime,
   * return 0
   IF m.startdate > m.enddate .OR. (m.startdate = m.enddate .AND. ;
        m.starttime > m.endtime)
       RETURN 0
   ENDIF

   #DEFINE secsperday 86400

   * determine whether the endtime is earlier or later than the
   * starttime
   IF m.endtime >= m.starttime
       m.elapsecs = (m.enddate - m.startdate) * secsperday + ;
           (time2secs(m.endtime) - time2secs(m.starttime))
   ELSE
       m.elapsdays = 0
       IF m.enddate - m.startdate > 0
           m.elapsdays = m.enddate - m.startdate - 1
       ENDIF
       m.elapsecs = (m.elapsdays * secsperday) + ;
           (secsperday - time2secs(m.starttime)) + ;
           time2secs(m.endtime)
   ENDIF

   RETURN m.elapsecs


   FUNCTION time2secs
   * passed a C8 HH:MM:SS string
   * returns the number of seconds into the day this is
   PARAMETER m.passedtime

   m.retsecs = VAL(RIGHT(m.passedtime, 2)) + ;
       60 * VAL(SUBSTR(m.passedtime, 4, 2)) + ;
       3600 * VAL(LEFT(m.passedtime, 2))
   RETURN m.retsecs