Daniel James
2009/12/18 Joaquin M Lopez Munoz
: No, it's more general than this: assume we've got a container with elements
a1, a2, ... , an, k1, k2, ... , km, b1, b2, ... , bl
where k1, ... , km are equivalent (and the rest are not equivalent to these). Put A=[a1,k1), K=[k1,b1), B=[b1,end]. Now if we insert an element equivalent to these in K using hint p, then:
* if p is in A, insertion takes place before k1, * if p is in K, insertion takes place before p, * if p is in B, insertion takes place before b1.
Looking at n3000, only associative containers' 'insert' is specified this way. For 'emplace_hint', it says:
equivalent to a.emplace(std::forward<Args>(args)...). [...] Implementations are permitted to ignore the hint.
which I think means that the element is placed at the end of the equivalent elements. There are similar definitions for unordered containers' 'insert' with hint and 'emplace_hint'. Presumably this is a defect?
I think you've spotted a defect in the case of associative containers. As for the unordered associative containers I don't see an issue, since insert in this case does not specify in any case the point of insertion (except to the extent that equivalent elements must stay together.) Joaquín M López Muñoz Telefónica, Investigación y Desarrollo