With your summing up of the quotation, I think you're again being too strict. If the standard doesn't define undefined behaviour, which it doesn't - well, what

With your summing up of the quotation, I think you're again being too strict. If the standard doesn't define undefined behaviour, which it doesn't - well, what then? You claim this renders any program that invokes undefined behaviour meaningless; I claim (as I think the standard wording implies) that this simply means the standard doesn't define the results, which then necessarily depend on the implementation in question. (It may be OK for anything to then happen, but as a simple question of quality - and common decency ;) - an implementation should strive to ensure that the result is not terribly surprising to anybody familiar with the system in question. And I'm not really sure that what gcc does in the face of undefined behaviour, conformant though it may be, passes that test.)