[fpc-pascal] IS operator and library created objects

[Torsten Bonde Christiansen]

On 2015-08-20 08:06, Sven Barth wrote:
>
> Am 20.08.2015 03:42 schrieb "Fabio Luis Girardi" 
> <fluisgirardi at gmail.com <mailto:fluisgirardi at gmail.com>>:
> > Currently, I'm doing a small program that uses libraries, objects 
> and the operator IS, that is know that this operator fails because of 
> duplication of VMT.
>
> And /that/ is one of the reasons why dynamic packages were invented...
>
> >
> > Everyone know some alternative (or more elegant) method to test if a 
> object created on a library is a class descendant without use 
> object.ClassName? Or in case of use String to check the class name, 
> how retrieve the class name of all descendant classes from a object?
> >
>
> Nope, there is no more elegant way. And you'll probably need to walk 
> the class tree using ParentClass and retrieve each name.
>
> Note: an except-handler will suffer from the same problem if it needs 
> to catch an exception that was raised from the library (or the other 
> way round).
> You are going to a extreme fragile direction there.
>
What about TObject.InheritsFrom(aclass : tclass) - Is that not the 
equivalent of the *IS* operator

-Torsten.
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