> They were careful to say "under the rules of C," Yes, and under the rules of C, division by zero has a side effect, namely invoking undefined behaviour. > T

> They were careful to say "under the rules of C," Yes, and under the rules of C, division by zero has a side effect, namely invoking undefined behaviour. > The problem for me is that the compiler is not obliged to check that the code is following the rules. That part's actually fine (annoying, but ultimately a reasonable consequence of the "rules the compiler can check" issue); the real(ly bad and insidious) problem is that when the compiler does check that the code is following the rules, it's allowed to do it in deliberately backward way that uses any case of not following the rules as a excuse to break unrelated code.