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

[Brian Drummond <brian@shapes.demon.co.uk>]

On Mon, 11 Jan 2016 13:17:20 -0500, Bob Duff wrote:

> Brian Drummond <brian@shapes.demon.co.uk> writes:
> 
>> Somehow I expected "extended return" to allocate space and "build in
>> place" during the execution of the return statement.
> 
> Build-in-place is done for return of immutably-limited types,
> whether or not the extended return syntax is used.
> 
> For nonlimited types, the compiler is free to use build-in-place if it
> can prove that it's equivalent to return-by-copy.  It's often not
> equivalent.  For example:
> 
>     X := Init;
> 
> What if Init raises an exception after partly modifying the result? In
> that case X should not be modified, so the result object of Init and X
> had better not be at the same address.

Thank you (and Simon and Brad) for the clarification. 

I had not considered the ramifications in the case of exceptions, and the 
impracticability of rolling back a partially modified object...

-- Brian