Re: Why scoped_ptr dost provide custom deallocation?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-02-14 06:05:16

dlux42 <dlux_at_[hidden]> wrote:
> And what if you use the deallocator as a template parameter?
>
> + It does not cost extra space
> + Don't need to use an extra reference-counted pointer
> - The interface is not consistent with shared_ptr
>
> How about that? I would be happy to see this advancement in the
> scoped_ptr class.

The main reason that scoped_ptr doesn't provide this feature is that nobody
made a convincing case for it.

(An example of a convincing case: "In my project I have encountered the
following situation: <description with real(istic sounding) identifiers> and
I believe that scoped_ptr<X, D> would be a perfect fit." Some non-examples:
"Someone might find it useful." "Wouldn't it be cool if...")

I suspect that most people just use editor inheritance or specialize
~scoped_ptr.

> Anyway: Do you know any smart-pointer class, which supports custom
> deallocator and can transfer ownership? (auto_ptr does not support
> custom deallocator and either smart_ptr or shared_ptr does not support
> release() method).

No. auto_ptr<X, D> would indeed be useful, but many compilers can't handle
the machinery that is needed to build an auto_ptr, which is probably why
there are few auto_ptr reimplementations and enhancements around.