Re: Extended return question

[christoph.grein@eurocopter.com]

On 11 Jul., 09:39, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> On Thu, 10 Jul 2008 20:43:09 -0400, Robert A Duff wrote:
> > I don't see any problem here.  The "notion of limited type" is "do not
> > copy".  In the example below, X is created, then destroyed, then another
> > X is created, and that becomes the result.  No copying.
>
> No, we cannot say that, because
>
> A) X is not created until the constructing function returns. There is just
> no X until that point. The question is *what* was created and destroyed? It
> is improperly typed, at least.
>
> B) On the other hand, if we considered X being created, destroyed and
> created again, then the name X would resolve into two different objects in
> the same context. This would either violate the identity semantics of X or
> be semantically equivalent to an assignment of X.

I view it this way:

There is a certain storage region where something (first X) is created
and then distroyed.

There is again a certain storage region (may be the same, may be not)
where the second X is created. Only when the function returns becomes
this storage region known a the final limited object. No copying.