Hi, I am already using the unordered_map implementation from the file vault. I have got some problems with unordered_map, because it offers no "lower_bound" (it is not a problem of the implementation, it is simply not in the specs). My question is, why is that so and what can I do about it? The use case is an efficient insert when I have to take special actions when the key is already in the container. For a map this would work like: iter = lower_bound(key); which gets the first element greater or equal to key Now I can check if the key is already in the map and execute some action to handle this case. Then I can insert the new element in the map with the "hint"-version of insert: mymap.insert(iter, newelement); The hint-version starts searching at the hint for the correct insertion point, so we don't have to search through the map twice. It is strange that such a hint-insert also exists for the unordered_map. But what hint could I give it, if I don't have lower_bound? Thanks, Martin PS: there is a small problem in hash_table.hpp causing a warning in VC7.1 line 278 should be: return (*prev_ptr)!=0; instead of return *prev_ptr;