[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 374

function CompareDateTime(

  const A: TDateTime;

  const B: TDateTime

):TValueRelationship;

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.

See also

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.

Documentation generated on: May 14 2021