Yeah, they changed the wording from "should" to "must" be O(1) in C++11, which means that before, even when they encourage the implementer to do it constant, th

Yeah, they changed the wording from "should" to "must" be O(1) in C++11, which means that before, even when they encourage the implementer to do it constant, that was in fact optional. I don't that tracking the size would be a big deal, if you think that doing that they wouldn't be a linked list any more, you could think it as a linked link wrapper. In any case the complexity guarantees of all the other operations remain true so I don't think it is a big deal.