Julian Date

Here's a function to calculate Julian Day number for the specified day, month, year. If the year is B.C. it must be negative.

/*  public long uf_JulianDate ( integer ai_Day, integer ai_Month, integer ai_Year )   */
DOUBLE  lr_ycorr
LONG    ll_Day, ll_Month, ll_Year, ll_ca, ll_cb, ll_RetVal = 0

ll_Day = Long( ai_Day );  ll_Month = Long( ai_Month );  ll_Year = Long( ai_Year );

IF ll_Day > 0 OR ll_Month > 0 OR ll_Year > 0 THEN
    IF ll_Year > 0 THEN
        lr_ycorr = 0.0
    ELSE
        lr_ycorr = 0.75
    END IF
    
    if ll_Month <= 2 THEN
        ll_Year  = Long( ll_Year  -  1 )
        ll_Month = Long( ll_Month + 12 )
    END IF
   
    ll_cb = 0
   
    IF ( ( Double( ll_Year ) * Double( 10000.0 ) + Double( ll_Month ) * Double( 100.0 ) + &
         Double( ll_Day ) ) >= Double( 15821015.0 ) ) THEN
      ll_ca = Long( ll_Year / 100 )
        ll_cb = Long( 2 - ll_ca ) + Long( ll_ca / 4 )
    END IF
   
    ll_RetVal = Long( Double( 365.25  ) * Double( ll_Year ) - lr_ycorr ) +  &
                    Long( Double( 30.6001 ) * Double( ll_Month + 1 ) ) +  &
                    Long( Double( ll_Day  ) + Double( 1720994.5 ) + Double( ll_cb ) )
END IF

RETURN ll_RetVal