RE: [boost] Variant implementation change (was re: unions)

From: E. Gladyshev (egladysh_at_[hidden])
Date: 2003-10-08 20:14:43

--- Brock Peabody <brock.peabody_at_[hidden]> wrote:
[...]
> > Some people argured that it is not possible to ensure
> > basic exception safety w/o backup heap.
> > I guess it is not true?
> 
> He's not saying that, he's just saying that the no-throw default
> constructible type no longer has to be the first one in the list for it to
> be used as the fallback type.

Yeah, you are right. I missinterpreted it.

> > If the user doesn't provide a nothrow default-constructible type,
> > perhaps variant should use an internal (1 char or 0 size)
> > nothrow default-constructible type and set an 'undefined'
> > flag similar to the 'backup' flag that you already have.
> 
> I think this is the same as the 'singular' solution that was discussed
> earlier.  

I realize it now.
I think that it is ok to have a singular variant.
It should be treated as unallocated memory
any access to it should generate an exception.

Eugene

__________________________________
Do you Yahoo!?
The New Yahoo! Shopping - with improved product search
http://shopping.yahoo.com