🚀 go-pugleaf

In article <4djrn4$js1@engnews1.Eng.Sun.COM> clamage@Eng.Sun.COM (Steve Clamage) writes:

> That point has been beaten to death in the C++ committee and also in
> this forum. Some people felt an auto_ptr should be able to have multiple
> owners, but people with experience with this kind of design persuaded
> the committee that auto_ptrs are too hard to use unless they can have
> only a single owner. Thus, ownership is transferred upon copying.
> 
> That is, single ownership is a deliberate design decision based on the
> semantics an auto-ptr should have. It is not an implementation issue.

I thought it was generally agreed that auto_ptrs as currently defined
were broken---specifically, that the semantics of strict ownership,
constness, and the binding of temporary objects, ended up making an
auto_ptr nearly useless for returning a value from a function.  That's
unfortunate, since returning something from a function is one of the
situations when it's most important to have some safe wrapper class 
like auto_ptr.

I've spent a bit of time trying to come up with bright ideas for
fixing auto_ptr, but I don't really have any.  Reference-counted
pointers don't have this particular problem, though, and that might be
the best argument for putting rc_ptr in the standard in addition to
(or instead of) auto_ptr.
-- 
Matt Austern
SGI: MTI Compilers Group
austern@isolde.mti.sgi.com
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