Re: [fpc-devel] MinDateTime is 100 AD ?
Op Mon, 2 Jul 2007, schreef Joost van der Sluis:
> 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 = 2958465.9;{ 12/31/ 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?!?)
Most probably year 2000 releated. To easy conversions from two digit days
to four digit years, rules were introduced that years <100 need to be
interpreted as a two digit years. I am 99% sure that these values have
been designed with some of these rules in mind. I recommend against
changing.
Daniël___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
On Mon, 2007-07-02 at 22:25 +0200, Micha Nelissen wrote: > Joost van der Sluis wrote: > > I'll change it to 01/01/01. When it raises problems on windows, the db- > > testsuite will detect that. > > Isn't 01/01/01 just as arbitrary ? Yes, it is. Joost. ___ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
On Mon, 2007-07-02 at 22:32 +0200, Vincent Snijders wrote:
> On Mon, 02 Jul 2007 22:21:22 +0200
> Joost van der Sluis <[EMAIL PROTECTED]> wrote:
>
> > On Mon, 2007-07-02 at 22:07 +0200, Michael Van Canneyt wrote:
> > >
> > > 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 = 2958465.9;{ 12/31/ 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 :-)
> >
> > I'll change it to 01/01/01. When it raises problems on windows, the db-
> > testsuite will detect that.
>
> Just an idea, what happens if you assign '01/01/01' (the string) to a variant
> and then assign the variant to a tdatetime?
>
> Is it a date from the year 1901 or not?
It'll return 1901. If you supply '01/01/0001' it will return the year
0001 in fpc 2.1.4, and 1901 in fpc 2.0.4.
Joost.
ps: I meant 01/01/0001 for MinDateTime, offcourse.
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
Joost van der Sluis wrote: > I'll change it to 01/01/01. When it raises problems on windows, the db- > testsuite will detect that. Isn't 01/01/01 just as arbitrary ? Micha ___ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
On Mon, 02 Jul 2007 22:21:22 +0200
Joost van der Sluis <[EMAIL PROTECTED]> wrote:
> On Mon, 2007-07-02 at 22:07 +0200, Michael Van Canneyt wrote:
> >
> > 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 = 2958465.9;{ 12/31/ 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 :-)
>
> I'll change it to 01/01/01. When it raises problems on windows, the db-
> testsuite will detect that.
Just an idea, what happens if you assign '01/01/01' (the string) to a variant
and then assign the variant to a tdatetime?
Is it a date from the year 1901 or not?
Vincent
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
On Mon, 2007-07-02 at 22:07 +0200, Michael Van Canneyt wrote:
>
> 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 = 2958465.9;{ 12/31/ 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 :-)
I'll change it to 01/01/01. When it raises problems on windows, the db-
testsuite will detect that.
Joost.
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
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 = 2958465.9;{ 12/31/ 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.
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
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 = 2958465.9;{ 12/31/ 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.
Joost.
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
Re: [fpc-devel] MinDateTime is 100 AD ?
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 = 2958465.9;{ 12/31/ 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 ?
Michael.
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
