[Overview][Constants][Procedures and functions][Index] Reference for unit 'DateUtils' (#rtl)

# CompareDateTime

Compare 2 dates, taking into account the time of day

## Declaration

Source position: dateutil.inc line 361

 function CompareDateTime( const A: TDateTime; const B: TDateTime

## Arguments

 A First date-time to compare B First date-time to compare

## Function result

A negative number if A is earlier than B, zero if they are equal, or positive if A is later than B.

## Description

CompareDateTime compares two timestamps A and B and returns the following results:

< 0
if A is earlier in date/time than B.
0
if A and B are the same date/time .
> 0
if A is later in date/time than B.

 CompareTime Compares two times of the day, disregarding the date part. CompareDate Compare 2 dates, disregarding the time of day SameDate Check whether two TDateTime values have the same date part. SameTime Check whether two TDateTime values have the same time part. SameDateTime Check whether two TDateTime values have the same date and time parts.

## Example

```Program Example98;

{ This program demonstrates the CompareDateTime function }

Uses SysUtils,DateUtils;

Const
Fmt = 'dddd dd mmmm yyyy hh:nn:ss.zzz';

Procedure Test(D1,D2 : TDateTime);

Var
Cmp : Integer;

begin
Write(FormatDateTime(Fmt,D1),' is ');
Cmp:=CompareDateTime(D1,D2);
If Cmp<0 then
write('earlier than ')
else if Cmp>0 then
Write('later than ')
else
Write('equal to ');
Writeln(FormatDateTime(Fmt,D2));
end;

Var
D,N : TDateTime;

Begin
D:=Today;
N:=Now;
Test(D,D);
Test(N,N);
Test(D+1,D);
Test(D-1,D);
Test(D+OneSecond,D);
Test(D-OneSecond,D);
Test(N+OneSecond,N);
Test(N-OneSecond,N);
End.
```