On Wed, Oct 19, 2011 at 4:22 PM, Jeffrey Lee Hellrung, Jr. <jeffrey.hellrung@gmail.com> wrote:
Sounds like a very weak reason. Especially since: If an instance of iterator_range is constructed by a client with two iterators, the client must ensure that the two iterators delimit a valid closed-open range [begin,end).
If that's the rationale, it'd be better to add is_valid() or so.
What are the requirements on an iterator's difference_type, exactly?
I don't know.
Specifically, are you even guaranteed that it is always convertible to *some* unsigned integral type, much less specifically std::size_t? And, if so, how would you deduce such an unsigned integral type?
Good questions. But I don't think I know the answer. However, given a valid range, end() - begin() can't be negative. Right? Most other size() return an unsigned type. Returning a signed type results in signed/unsigned mismatches. Olaf