Re: Undefined behaviour with Non-static, non-polymorphic + null pointer?
Marco Manfredini wrote:
Alan Woodland wrote:
Thanks. It's funny, I'd never actually though about the implications
of that in this context before. Just found the following quote which
ought to convince certain people:
Event funnier: According to 5.2.5, this code:
struct X { static const int x=0; };
int main() {
X*x=0;
x->n;
}
invokes UB.
And if I'd was not to lazy to look it up, I could tell you if
struct X { enum {x=0}; };
int main() {
X*x=0;
x->n;
}
invokes UB or not.
(I mean, they could really make an appendix "Authoritative List of
UB's", because it's really a nuisance to find these only scattered
around in the Standard)
I am not sure how such a list would help. You would still have to
understand that the postfix expression (x->) dereferences the pointer
regardless what's following it. How would mentioning that if one
dereferences a null pointer it's UB help understanding that x->n
does in fact dereference 'x' (if 'n' is a static member)?
V
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