[fpc-devel] MinDateTime is 100 AD ?

[Michael Van Canneyt]

On Mon, 2 Jul 2007, Joost van der Sluis wrote:

> On Mon, 2007-07-02 at 21:48 +0200, Michael Van Canneyt wrote:
> > 
> > On Mon, 2 Jul 2007, Joost van der Sluis wrote:
> > 
> > > Hi all,
> > > 
> > > In sysstrh.inc MinDateTime is defined as follows:
> > > 
> > >   { For floattodatetime }
> > >   MinDateTime: TDateTime = -657434.0;     { 01/01/0100 12:00:00.000 AM }
> > >   MaxDateTime: TDateTime =  2958465.99999;{ 12/31/9999 11:59:59.999 PM }
> > > 
> > > Why is that? Datetimes before 100AD works perfectly. Can I change it to
> > > 01/01/01 ? (Why does this restriction exist at all?!?)
> > 
> > Delphi compatibility, probably. As far as I know, it's not used ?
> 
> It is used in cvarutil.VariantToDate and in sysstr.FloatTodateTime. 

Probably to avoid a conversion error ?
Maybe some Microsoft thing, that's where TDateTime comes from ?

The reason is probably lost in the mists of time :-)

Michael.