Re: [gtkmm] Replacing dynamic_cast<> with static_cast<> - compiler error.

["Paulo Pinto" <pjmlp progtools org>]

----- Original Message -----
From: "Nick Huxley" <nick anvil co uk>
To: "Murray Cumming" <murrayc usa net>
Cc: "Paulo Pinto" <pjmlp progtools org>; "gtkmm-main" <gtkmm-list gnome org>
Sent: Wednesday, September 18, 2002 12:23 PM
Subject: Re: [gtkmm] Replacing dynamic_cast<> with static_cast<> - compiler
error.


> On 18 Sep 2002, Murray Cumming wrote:
>
> > On Wed, 2002-09-18 at 12:15, Paulo Pinto wrote:
> > > Sorry for the naive question, but what is
> > > the relation between `Glib::ObjectBase *'
> > > and `Atk::Object *' ?
> >
> > http://www.gtkmm.org/gtkmm2/reference/html/classAtk_1_1Object.html
> >
> > It's a base class. Actually it's a virtual base class. I think I have
> > learnt that static_cast<> can never be used to cast down from a virtual
> > base class, so none of these dynamic_cast<>s can be changed to
> > static_cast<>s.
> >
>
> Unfortunately you are right. Since we're dealing with pointers for the
> polymorphism then the compiler can't know what will be passed in so a
> static_cast cannot be used. The dynamic_cast checks at run time and will
> throw an exception if the cast cannot be meaningfully performed.
>
> Nick


Right. I know that it doesn't sound pretty but we could replace the
dynamic_cast
with a reinterpret_cast or even an old style cast (ugh did I just said
that?).

Paulo Pinto