Re: [boost] [optional] problems with swap()

From: Fernando Cacciola (fernando.cacciola_at_[hidden])
Date: 2008-04-11 16:57:29

Frank Mori Hess wrote:
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> On Friday 11 April 2008 15:00 pm, Fernando Cacciola wrote:
>> Hi Thorsten,
>>
>> Adding the new requirement is out of the question, but it's definitely
>> possible to choose default construction or zero-initialization as
>> appropiate. And IMO that magic would be best placed within
>> boost::in_place() itself since it makes a lot of sense, given its nature,
>> to do
>> zero-initialization for non-default constructible types.
>>
>> With such a smart in_place factory, the optional swap implementation 
>> would
>> look exactly as you proposed it AFAICT.
>
> If I'm following, you're proposing calling swap on an object which doesn't
> really exist, but is just a zero'ed block of memory?  Wouldn't that be
> undefined behavior?
>
Yeap, it would... I'm writting nonsense already and the weekend haven't even 
started yet :)

Best

Fernando