Re: [boost] shared_ptr and is_convertible

From: David Abrahams (abrahams_at_[hidden])
Date: 2000-08-09 07:05:38

----- Original Message -----
From: "John Maddock" <John_Maddock_at_[hidden]>

> By using something like this internally in shared_ptr, the range of
> available convertions for polymorphic types would be greatly extended,
> without changing existing behaviour as far as I know.  The down side is an
> increase in complexity of the curently simple shared_ptr template.
>
> Thoughts?

Wouldn't this also allow code which implicitly converts unrelated types of
shared_ptrs to compile? I would really *hate* that:

struct X { virtual ~X(); };
struct Y { virtual ~Y(); };
void transmogrify(boost::shared_ptr<Y>);
boost::shared_ptr<X> xp( new X );

transmogrify(xp);// <== used to be an error. That was a GOOD thing.

Also, wouldn't it allow code which implicitly converts base to derived to
compile? I would really *hate* that, too.

-Dave