[fpc-devel] RTTI's GetPropValue returns corrupt Boolean value

[Graeme Geldenhuys]

On 20/11/2007, Michael Van Canneyt <michael at freepascal.org> wrote:
> It's hard to say whether this is an actual error or an incompatibility.

Well this 'error' has been around in tiOPF since I ported it to FPC
(about 3 years) and now it's really bugging me.  :)

> Looking at the code and the error, I'd say that somewhere along the line
> fpc converted a variant to int64 instead of to an integer as delphi seems
> to do.

No idea, I may not look at the Delphi code remember!  ;-)


> It's just one of these reasons why it is IMHO better not to use Variants:
> things happen behind the scenes that are not very clear (and that are
> not documented )

Fair enough. I'm not a fan of Variants either, but how else would I
write the PropertyMatch() function then?  Yes I could do some extra
tests and use GetStrProp, GetIntProp, GetFloatProp etc. but there
isn't a GetBooleanProp().  I would imagine I need to use the
GetOrdProp for Boolean, but looking at the function definition for
GetOrdProp, it outputs a Int64 which is probably what gave me the
error in the first place (casting Bool to Int64 or vice-versa).

Note that the PropertyMatch() function I have in the example is a
scaled down version (just to highlight the issue) of the full one in
tiOPF.  I need to handle all property types.


Regards,
  - Graeme -


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