[boost] Re: dynamic vs static cast (Was: assert in inline function w/o ODR violation)

From: Valentin Bonnard (Bonnard.V_at_[hidden])
Date: 1999-09-02 10:32:22

Beman Dawes wrote:
> 
> Kevlin Henney wrote:

> >        template<class Derived, class Base>
> >        inline Derived safe_downcast(Base* x)
> >        {
> >            assert(dynamic_cast<Derived>(x) != 0);
> >            if(false)
> >                dynamic_cast<Derived>(x);
> >            return static_cast<Derived>(x);
> >        }

> Kevlin, after wading throught the standard's description of
> dynamic_cast twice, I am still having trouble knowing which errors
> your added code will detect, and which will still get through.  Could
> you enlighten me?

dynamic_cast from a base class w/ no virtual functions 
to a derived class is ill-formed, but static_cast in 
such case is well-formed.

That's the only difference in static semantic I can 
think of for the moment.

-- 
Valentin Bonnard