Andrew Pinski wrote:
But the reason question is why make it an undefined behavior instead of an implementation defined? This would have made it clearer instead of allowing the compiler not document what happens. Or is C++ just following C here? In which case it might be better to ask the C committee why it was done this way and real definition of undefined for this case?
Note that implementation defined in practice is a fairly severe constraint. That's because you don't want to have a super complicated definition that takes a book to describe all the horrible things that might happen, so in practice you are pushed into some simple decision (always traps, always saturates, always wraps etc for the case of overflow).
