The associative containers with unique keys and the unordered containers with unique keys have a member function insert that returns a nested type insert_return_type. That return type is a specialization of the type specified in this subclause.
template <class Iterator, class NodeType> struct INSERT_RETURN_TYPE{ Iterator position; bool inserted; NodeType node; };
The name INSERT_RETURN_TYPE is exposition only. INSERT_RETURN_TYPE has the template parameters, data members, and special members specified above. It has no base classes or members other than those specified.