Minimum and maximum value of TDateTime

[LemonParty]

What is the minimum and maximum values of TDateTime?

[BrunoK]

Code: Pascal  [Select][+][-]

1. program Project1;
2. uses
3. SysUtils;
4.  
5. begin
6.   writeln(DateTimeToStr(MinDateTime), ' - ', DateTimeToStr(MaxDateTime));
7.   readln;
8. end.

[LemonParty]

I was searching MinDateTime and MaxDateTime values in DateUtils unit.
Thank you.

[dsiders]

Code: Pascal  [Select][+][-]

1. program Project1;
2. uses
3. SysUtils;
4.  
5. begin
6.   writeln(DateTimeToStr(MinDateTime), ' - ', DateTimeToStr(MaxDateTime));
7.   readln;
8. end.

And if you notice, the comment in the FPC 3.2.2 source code does not match the actual value in MinDateTime.

Comment says:

Code: Pascal  [Select][+][-]

1. MinDateTime: TDateTime =  -693593.99999999; { 01/01/0001 12:00:00.000 AM }

The output value from FormatDateTime says:

Code: Pascal  [Select][+][-]

1. 01/01/0001 23:59:59.

[Thaddy]

A suggestion to rephrase the comment ( from CoPilot ) which is correct is:
"MinDateTime: TDateTime = -693593.99999999;
{ Represents 01-Jan-0001 at 23:59:59, using the day-fraction convention
  (integer = days offset from 30-Dec-1899, fraction = time of day). }
"

[ASerge]

Maybe change the value of MinDateTime to 693593.0?

Code: Pascal  [Select][+][-]

1. {$MODE OBJFPC}
2. {$IFDEF WINDOWS}
3.   {$APPTYPE CONSOLE}
4. {$ENDIF}
5.  
6. uses DateUtils;
7.  
8. const
9.   Date1 = -693593.99999999;
10.   Date2 = -693593.0;
11. begin
12.   Writeln('Double1 < Double2: ', Date1 < Date2);
13.   Writeln('DateTime1 < DateTime2: ', CompareDate(Date1, Date2) < 0);
14.   Write('Press Enter to exit...');
15.   Readln;
16. end.

For TDateTime types, the fractional part is always assumed positive, so the negative time part must be processed using its absolute value.