Re: Should GCC publish a general rule/warning due to it's default presumption of undefined signed integer overflow semantics?

[Gabriel Dos Reis <gdr@integrable-solutions.net>]

Andrew Pinski <pinskia@physics.uc.edu> writes:

| On Jun 30, 2005, at 8:48 PM, Gabriel Dos Reis wrote:
| 
| > | Really?  You've talked to Stroustrup?
| >
| > I work with him on daily basis, and as a matter of fact we've discussed
| > the heart of this topic of this thread yesterday over lunch.  But, as
| > much as I hate argument by authority I could not let this discussion
| > goes on the slope it is taking without saying what I understood from
| > discussion with him on the topic.  It wasn't meant as a proof.  Just a
| > data point.  Of course, it is far preferable he speaks for himself but
| > it is hard to have him take part of a debate where extreme abstract
| > arguments are more dominant than balance between two apparant
| > conflicting goals. And that is, I guess, a wise thing to do just as
| > core developers like RTH may have a say on this very issue :-)
| 
| But the reason question is why make it an undefined behavior instead of
| an implementation defined?

I cannot tell you exactly why it was made undefined behaviour.  But,
I can tell you from experience working in the C++ committee that there
may be various reasons why something is left undefined (including
oversight), not just because the committee thought it would be fun.
In this specific case, I think (but I'm not 100% sure) it is a carry
over from C90 (like many other "curious" cases). 

-- Gaby