Hi Gaby,
There is something that we knoq about the code, that the compiler
does not have: we expect a sequence denoted by its first and last
element, so that the difference is always positive. However, the
difference of pointers is defined in the language as an ptrdiff_t (a
signed type). No wonder what people invented ssize_t :-)
I believe we have to investigate further what promises we want make
and hold through max_size() and change the code according to that.
First, I want to tell you that I agree with your general point of view,
here and elsewhere, in particular about the tension existing between
difference_type and size_type: as a matter of fact, when, time ago, I
noticed some differences between our vector and deque implementations, I
wrote something about it in private mail to Howard, but we didn't pursue
the issue much...
Coming to the specific issue, and *assuming* we agree about the
usefulness of warning for signed -> unsigned, maybe we are "lucky", in
this sense: Table 65 says *explicitely* that size_type can represent any
non-negative value of difference_type. Thus, as I see the issue, we can
safely cast from the latter to the former, if we want, without entering
in the larger discussions mentioned above... What do you think?
Paolo.
