Gabriel Dos Reis wrote:
It highly depends on what you define to be pointer arithmetic.
Given the conversions
pointer -> integer type
integer type -> pointer
T* -> U*
Yes, but the only defined semantics of these conversions is that you get
the same
pointer back, you cannot say anything else about the values. If you add
one to
the integer, you have no assurance that it has anything to do with
adding one
to the pointer. Yes, it probably will, but there is no guarantee in the
standard.
I think your sentence is way to restrictive and does not capture C
models.
Well part of the trouble is that there are really two models here, the
one in the
standard, and the one that everyone expects and which is by and large
the one
that is implemented.
Richard, to resolve this issue, we need to be more precise about our
mappings for
pointer -> integer type
integer type -> pointer
T* -> U*
conversions. This is not an issue to resolved in isolation, piece meal.
There is no obligation standard-wise to say anything at all about these
conversions,
other than they are value preserving, i.e. if you convert a pointer to
an integer
that is large enough, and back to a pointer, you get the pointer back.
As far as I
know nothing more can be said.
-- Gaby
