RE: [Re: [gtkmm] ANNOUNCE: gtkmm 2.2.8]

[Murray Cumming Comneon com]

> From: Chris Vine [mailto:chris cvine freeserve co uk] 
> I will not be installing gtk+-2.3.  Once gtk+-2.4 is out 
> against which I can 
> test gtkmm-2.3, I will submit a patch unless someone has 
> already done that.

I think it is sensible not to install gtk+ 2.3 on top of gtk+ 2.2 yet, but
that does not mean that we should not be using it for development. It is
very easy to use a separate, additional, install prefix. And it is very very
easy with jhbuild (from gnome's cvs).
 
> > I think that, wherever a static_cast<> worked, a C-style cast (or a
> > reinterpret_cast<>) is probably OK. If multiple-inheritance 
> was an issue
> > there then we would have had to use a dynamic_cast<> 
> anyway.  In this case, 
> > the class is not multiply inherited.
> 
> This is not quite right.  A static_cast casting down an 
> inheritance path will 
> carry out offset calculations where necessary, and one case 
> where it is 
> necessary is multiple inheritance.  A static_cast of pointers 
> and references 
> can be used with multiple inheritance unless the inheritance 
> is virtual and 
> the cast is from a shared base class (that is, the 
> inheritance tree is 
> diamond shaped), in which case as you say a dynamic_cast must 
> be used when 
> casting from the virtual base to a child which inherits it 
> from two parents.  
> The offset calculations made by the compiler with a valid 
> static_cast with 
> multiple inheritance will not occur with a reinterpret_cast, 
> so the two will 
> not necessarily give the same result.

Yes, I was thinking of virtual inheritance, not just multiple inheritance.

Murray Cumming
murrayc usa net
www.murrayc.com