Re: [review][fixed_string] End of review period approaching and a plea

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2019-12-04 18:30:23

On 2019-12-04 18:24, Alexander Grund via Boost wrote:
> 
>> I would hope to see close to the same semantics as std::array<T,0>,
>> which I believe allows data() to return nullptr.
> 
> I don't think so:
> 
> "There is a special case for a zero-length array (|N == 0|). In that 
> case, array.begin() == array.end(), which is some unique value. The 
> effect of calling front() or back() on a zero-sized array is undefined." 
> from https://en.cppreference.com/w/cpp/container/array
> 
> IMO this excludes nullptr as that won't be unique

I don't think iterators from different instances of a container are 
comparable. IOW, "unique" means distinct from any possible values of 
valid iterators obtained from this particular container instance.

That might not apply to pointers, though. I don't remember whether there 
are any guarantees wrt. data() of a zero-sized array, for example.