#include <boost/intrusive/avl_set.hpp>

typedef void *Type;

struct EntryType {
  EntryType(Type id) : id(id) {}
  Type id;
  typedef boost::intrusive::avl_set_member_hook <> AvlHook;
  AvlHook avl_by_id_hook;
  struct CompareById {
    bool operator()(const EntryType &a,const EntryType &b) const
      {return (a.id < b.id);}
  };
  struct KeyCompareById {
    bool operator()(const Type &id,const EntryType &b) const
      {return (id < b.id);}
    bool operator()(const EntryType &a,const Type &id) const
      {return (a.id < id);}
  };
};

typedef boost::intrusive::avl_set<
          EntryType,
          boost::intrusive::member_hook<
            EntryType,
            EntryType::AvlHook,
            &EntryType::avl_by_id_hook
          >,
          boost::intrusive::compare<EntryType::CompareById>
        > SetById;

void foo(SetById &s,const Type &x) {
  s.find(x,EntryType::KeyCompareById());
}