Re: C++0x and Threads - a poor relation to Ada's tasking model?

[REH <spamjunk@stny.rr.com>]

On Aug 14, 10:30 am, John McCabe <j...@nospam.assen.demon.co.uk>
wrote:
> Not significantly as far as I can see; C++ says behaviour on overflow
> on signed integers is undefined, and C seems to say that it's up to
> the implementation (which seems like the same thing). Both say
> unsigned overflow doesn't occur because they use modulo arithmetic.
>
> Unless of course I'm looking in the wrong place.
>

No, you're not. They both say that signed integer overflow is
undefined behavior. They diverge when it comes to other portability
guarantees. Both C and C++ have guaranteed minimum ranges (e.g., int
must be at least +/- 32767), and that each successive int type (that
is char, short, int, long, etc.) must at least support the range of
the one before it. It gets nasty after that because (if I remember
correctly), only C++ says that the SIZE of an integer type must also
be least as big as the one before it. I believe it is technically
acceptable for an implementation of standard C for sizeof(int) to be
larger than sizeof(long). This is, of course, pedantry on my part but
I just wanted to show that isn't safe to assume that C and C++ share
the same rules.

REH