From: Bronek Kozicki (brok_at_[hidden])
Date: 2004-08-27 10:49:00
Howard Hinnant wrote:
>> So that sizeof(move_ptr<T>) can be the same as sizeof(T*).
> Yes, yes! Absolutely zero-overhead over a raw pointer is (imho) a
> critical design criteria of this type of smart pointer. And the reason
> for the ::type dance instead of something more direct like:
> template<class T, class D = detail::default_delete<T> >
OK, I guess that detail::default_delete<T> is going to be stored as
static field of move_ptr class. However ...
> 2. And the deleter itself should be able to be a reference type.
> I can't stress this second point enough. It is a real feature when you
> want to allow for the possibility of a deleter that is both state-full
> and heavy. In templated code that already owns a deleter (that you
> don't know anything about, except its name), and you're using the
> move_ptr just to enforce ownership temporarily (say for exception safety
> purposes), then passing a reference-typed deleter to the move_ptr is an
> extremely elegant solution:
> Code templated on P (p : pointer type) and D (d_ : deleter type):
> move_ptr<P, D&> hold(p, d_); // grab hold of p, using a D&, as
> opposed to a D
... how are you going to store reference to deleter object here, without
any memory overhead in your pointer object?
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk