Re: Why is the destructor called multiple times after I declare an object?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 13/01/2016 01:02, Robert A Duff wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
>
>> On 2016-01-12 21:21, Randy Brukardt wrote:
>>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
>>> news:n72hag$bjq$1@gioia.aioe.org...
>>>> On 12/01/2016 00:44, Randy Brukardt wrote:
>>>>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
>>>>> news:n715oq$fae$1@gioia.aioe.org...
>>>>>> On 2016-01-11 19:17, Bob Duff wrote:
>>>>>>> Build-in-place is done for return of immutably-limited types,
>>>>>>> whether or not the extended return syntax is used.
>>>>>>
>>>>>> But you can leave one return statement on an exception, catch the
>>>>>> exception, and then return through another return statement, with other
>>>>>> discriminants and even other type of the result (if it is class-wide).
>
> Yes.  Or you can 'goto' or 'exit' out of an extended return.
>
>>>>>> Therefore the result can be potentially allocated and reallocated any
>>>>>> number of times. In which sense is this behavior 'in-place'?
>
> "In place" means that the returned object created by the return
> statement that actually returns is the same object as the one at the
> call site.

It is rather a useless definition, because it would apply to the objects 
returned by-copy as well. At some point *some* object created as a 
result of a call to the callee becomes the object of the caller.

To my understanding Randy's definition tried to address this by claiming 
absence of intermediate objects (as a generalization of the notion of 
copying).

> Note that this point has nothing to do with extended_return syntax.

Right. Also neither and no definition will work ever. Whichever syntax 
"same" object cannot be "returned".

> The RM doesn't define "location".  And the rules about 'Address are
> pretty loose.  And GNAT is correct here.

I didn't doubt it. The example was for the sake of argument. If RM 
attempted to define "same" location in a useful way that would make 
reasonable implementations impossible.

> Now, now, that's just sniping.

Yes, yes, I fired back at an attempt to evade discussion by the game of 
definitions. (:-))

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de