Boost.MultiIndex: How to make an efficient intersection of a set?

Question

Suppose we have data1 and data2 . How can I cross them with std::set_intersect() ?

 struct pID { int ID; unsigned int IDf;// postition in the file pID(int id,const unsigned int idf):ID(id),IDf(idf){} bool operator<(const pID& p)const { return ID<p.ID;} }; struct ID{}; struct IDf{}; typedef multi_index_container< pID, indexed_by< ordered_unique< tag<IDf>, BOOST_MULTI_INDEX_MEMBER(pID,unsigned int,IDf)>, ordered_non_unique< tag<ID>,BOOST_MULTI_INDEX_MEMBER(pID,int,ID)> > > pID_set; ID_set data1, data2; Load(data1); Load(data2); pID_set::index<ID>::type& L1_ID_index=L1.data.get<ID>(); pID_set::index<ID>::type& L2_ID_index=L2.data.get<ID>(); // How do I use set_intersect? 

Answer 1

 std::set_intersection( L1_ID_index.begin(),L1_ID_index.end(), L2_ID_index.begin(),L2_ID_index.end(), output_iterator, L1_ID_index.value_comp());