Return the period (in years, months, days) between two dates.
Source position: dateutil.inc line 286
procedure PeriodBetween( 
const ANow: TDateTime; 
const AThen: TDateTime; 
out Years: Word; 
out months: Word; 
out days: Word 
); 
PeriodBetween returns the timespan between 2 dates (ANow and AThen), expressed as a number of years, months and days in the parameters Years, months and days. Only complete years, months and days are reported.
If ANow is before AThen, their values are reversed so the result is always positive.

Calculate the number of whole years between two TDateTime values. 


Calculate the number of whole months between two TDateTime values. 


Calculate the number of whole weeks between two TDateTime values. 


Number of whole days between two TDateTime values. 