Re: [boost] Boost.Optional advantages

From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-07-11 18:30:15

David Abrahams wrote:
>> but in my opinion, "implementation defined" doesn't equal
>> "nonportable" in this particular case. (Alignment problems
>> notwithstanding.)
>
> There's "nonportable according to the standard" and "nonportable in
> practice."  This one is only the former, it's true.  But why write
> something that might turn out to be nonportable somewhere when we can
> do something that the standard guarantees?

Because it's clearer, it (arguably) matches the intent of the standard (see 
9.2/17), and because deducing that T* -> void* -> char* is guaranteed to 
work correctly is nontrivial. I suspect that 5.2.10 doesn't give semantics 
to T* -> char* only because "everyone knows" how this conversion is supposed 
to work. It's probably a defect.