Re: [Somelib] Errors with downcasting using SOME::Object

[John P. (Quinticent) <jo...@ma...>]

Linux/gcc -

Hierarchy:

              mriIAsset
                   /    \
                 /        \
mriIVisualAsset   mriIAudioAsset    (There will be more in the future)

I think the whole problem is that SOMELib uses some sort of smart pointers
that I haven't looked into.  Tom is using them in SOME::Object.

SOME::Object<T> expands to class SOME::Object : public boost_smart_ptr<T>

I haven't looked at the boost stuff and I am not sure if boost_smart_ptr isA
T or hasA T.  If it is hasA this will have to change.  If it cannot be
downcast then it needs to be taken out of SOMELib as I am not sure what
benefits it gives.

-Quinticent

"Frank V. Castellucci" wrote:

> What is the hierarchy? You may need dynamic_cast<> based on the rules of
> usage in 1998(E) C++ standard.
> What is the error, and what is the compiler/platform?
>
> John Palmieri wrote:
> >
> > I am trying to integrate SOMELib into snaglepuss and am having errors
> > with downcasting my objects.
> >
> > You see I have a hiarchy of interfaces for use with dynamicly loadable
> > assets (png, mp3, mpg files).  They all get loaded and stuffed into
> > chests which are just glorified vectors of type mriIAsset *.  Now each
> > of the assets can be rendered to the screen, audio device, etc. with a
> > call to the render() method.  But, each type of asset also has enhanced
> > functionality based on their type so my png loader asset would also
> > inherit the interface mriIVisualAsset which would in turn inherit the
> > mriIAsset interface.  The problem I am having is that when I load my
> > object I check to see if it is visual, audio.  Let's say it is a visual
> > asset.  I then use this code to construct the object:
> >
> > SOME::Object<mriIVisualAsset>oAsset(assets[0]);
> > //construct our asset
> > if(!oAsset.construct()){ ...
> >
> > this works fine but now I want to add this asset to my chest:
> >
> > asset = static_cast<mriIAsset *>(oAsset);  //error here.  I'm guessting
> > the template is not truly inheriting
> >
> > chest->addAsset( chestpos, asset );//I should be able to mix and match
> > different assests in my chest
> >
> > This is an important feature and as much as I know you love the boost
> > stuff if it restricts projects from using standard C++ mechanisms when
> > working with SOMELib it will have to go.
> >
> > -Quinticent
> >
> > _______________________________________________
> > somelib-devel mailing list
> > som...@li...
> > http://lists.sourceforge.net/mailman/listinfo/somelib-devel
>
> --
> Frank V. Castellucci
> http://corelinux.sourceforge.net
> OOA/OOD/C++ Standards and Guidelines for Linux
> http://PythPat.sourceforge.net
> Pythons Pattern Package
> _______________________________________________
> somelib-devel mailing list
> som...@li...
> http://lists.sourceforge.net/mailman/listinfo/somelib-devel