I already addressed this. There's no flipping, they mean the same thing in this context; epoll was supposed to allow the expression of a certain class of programs, but it instead instead encouraged a bunch of broken, fragile programming patterns, and epoll tiself required numerous revisions and extensions to to actually get the behaviour it should have had to begin with, and also limited to a subset of the kernel abstractions kqueue supports. That's considerably worse than kqueue to the point where it's broken. I don't see any further need to discuss it frankly, we've each said our piece.