What is the difference between the unordered concurrent map and the concurrent hash map? What I mean is, why would I want to chose one over the other? The documention doesnt necessarily explain the pros and cons of the two, but only explains a few differences in functionality without explaining why the differences exist. Are there speed differences in insert? the unordered container cannot saftely erase objects --great. So why would anyone use unordered concurrent map?
Also, a follow up question, is there a way to iterate over the concurrent hash map without holding locks for each element as I go? For example, I know that a certain part of my code is going to be serial and I want to iterate over the container and do some work, is there a way to skip the automatic locking?