'goto" gone from computer languages or is it!

Tim Riker wrote: undefined really does mean undefined. The compiler could call printf with any three values it has lying around and still be conforming. The order of argument evaluation is explicitly left unspecified so as to give the implementation more freedom to optimise. There is no 1st,2nd,3rd - the arguments might be evaluated from the middle outwards or the outside inwards or whatever makes sense. You cannot even assume that if you write that line out twice, that the order of evaluation will be the same the second time round. If the printf is within a loop, the order of evaluation might vary on each invocation. Optimisers do all kinds of fun stuff! Since the behaviour is undefined, anything can happen. In practice the compiler won't turn into a bowl of geraniums, but it could do something far worse, and emit code that does whatever it is that you might have expected. That way you think you've written something reasonable only to find that it all blows up horribly when the platform changes or you get a new compiler or you update your existing compiler or whatever. About the only thing that is guaranteed is that, if you fall prey to this problem, your QA org will miss the problem and your customers will find it :-) To top it all, you cannot even be sure what the value of i will be after the call. I think gcc 3.3 spots this kind of thing (and the other common variant: a[++i] = ++i; Antonio -- --------------- Antonio Carlini arcarlini at iee.org