Since I'm on a comment spree today: I think we mostly agree, actually, but note that the compiler doesn't have to pick 0 for the undefined value at all. It only

Since I'm on a comment spree today: I think we mostly agree, actually, but note that the compiler doesn't have to pick 0 for the undefined value at all. It only does that because that's the most convenient value to pick. (And for the code path where it's deduced to be 0, well it's not really picking, it doesn't have a choice =] ) A compiler with less optimizations could chose to spill the "ret" variable and not pick a value at all, for example. It would just return whatever happens to be lying on the stack if you took the unitialized path.