lparameters tdDOB, tdDate
IF parameters() = 1
tdDate = date()
ENDIF

return (year(tdDate) - year(tdDOB) - ;
iif( str(month(tdDate),2) + str(day(tdDate),2) < ;
str(month(tdDOB),2) + str(day(tdDOB),2), 1, 0) )