From: William Kempf (sirwillard_at_[hidden])
Date: 2000-11-22 15:16:28
--- In boost_at_[hidden], "Peter Dimov" <pdimov_at_m...> wrote:
> From: "William Kempf" <sirwillard_at_m...>
>
> > As for ref-counting vs. cloning... that's a trickier question.
>
> Indeed. :-)
>
> > I'm
> > leaning in favor of ref-counting since a callback is likely to be
> > passed around frequently.
>
> That's not obvious to me. Why is a callback likely to be passed
around
> frequently - in performance critical code?
Well, I'm willing to concede that the term "frequently" is a
misnomer. I suppose that most general usages of a callback won't
copy more than a few times at the most. However, I was considering
how callbacks could be stored within a container which can cause
frequent copies to be made. There's ways around this, though, so
maybe I need to rethink my position here.
> > However, I'd love to hear a list of pros
> > and cons from people for both strategies just to make sure I've
not
> > missed any that could change my opinion (and to help others
formulate
> > their own opinions as well).
>
> A list of pros and cons won't help, because a cloning callback and a
> reference counted callback are different concepts. Sometimes you'll
need the
> one, sometimes the other.
This I'm not so sure about. Yes, their behavior is radically
different. However, I find it difficult to think of specific
situations where one would be the answer while the other would not.
Can you spark my thinking on this?
> One other point that crossed my mind is that building a refcounted
callback
> on top of a cloning one is (relatively) easy, while the opposite is
not
> trivial. Assuming the compiler has void returns, of course.
If both are truly useful then I'd agree that the cloning version is
the more important of the two.
Bill Kempf