Hi, To add, Hi, To add, When I insert like "sample.insert(&a);", I get errors like, . . . kytj.cpp ky_op_tj.cpp c:\code\common\lib\boost\boost\multi_index\hashed_index.hpp(1155) : error C2064: term does not evaluate to a function taking 2 arguments class does not define an 'operator()' or a user defined conversion operator to a pointer-to-function or reference-to-function that takes appropriate number of arguments c:\code\common\lib\\boost\boost\multi_index\hashed_index.hpp(1152) : while compiling class template member function 'bool boost::multi_index::detail::hashed_index<KeyFromValue,Hash,Pred,SuperMeta,TagList,Category>::link_point(Container *const ,boost::multi_index::detail::hashed_index_base_node_impl<Allocator> *&,boost::multi_index::detail::hashed_unique_tag)' with [ KeyFromValue=boost::multi_index::const_mem_fun<DBObject,Key1,DBObject::getKey1>, Hash=boost::multi_index::const_mem_fun<DBObject,Vs64,DBObject::getKey2>, Pred=boost::multi_index::const_mem_fun<DBObject,VString,DBObject::getEntityName>, SuperMeta=boost::multi_index::detail::nth_layer<1,Container *,boost::multi_index::indexed_by<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<DBObject,Key1,DBObject::getKey1>,boost::multi_index::const_mem_fun<DBObject,Vs64,DBObject::getKey2>,boost::multi_index::const_mem_fun<DBObject,VString,DBObject::getEntityName>>>,std::allocator<Container *>>, TagList=boost::mpl::vector0<boost::mpl::na>, Category=boost::multi_index::detail::hashed_unique_tag, Allocator=std::allocator<char> ] c:\code\common\lib\boost\boost\multi_index_container.hpp(100) : see reference to class template instantiation 'boost::multi_index::detail::hashed_index<KeyFromValue,Hash,Pred,SuperMeta,TagList,Category>' being compiled with [ KeyFromValue=boost::multi_index::const_mem_fun<DBObject,Key1,DBObject::getKey1>, Hash=boost::multi_index::const_mem_fun<DBObject,Vs64,DBObject::getKey2>, Pred=boost::multi_index::const_mem_fun<DBObject,VString,DBObject::getEntityName>, SuperMeta=boost::multi_index::detail::nth_layer<1,Container *,boost::multi_index::indexed_by<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<DBObject,Key1,DBObject::getKey1>,boost::multi_index::const_mem_fun<DBObject,Vs64,DBObject::getKey2>,boost::multi_index::const_mem_fun<DBObject,VString,DBObject::getEntityName>>>,std::allocator<Container *>>, TagList=boost::mpl::vector0<boost::mpl::na>, Category=boost::multi_index::detail::hashed_unique_tag ] c:\code\common\src\biz\model\stm-stow_model\stm_container_manager_abc.h(300) : see reference to class template instantiation 'boost::multi_index::multi_index_container<Value,IndexSpecifierList>' being compiled with [ Value=Container *, IndexSpecifierList=boost::multi_index::indexed_by<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<DBObject,Key1,DBObject::getKey1>,boost::multi_index::const_mem_fun<DBObject,Vs64,DBObject::getKey2>,boost::multi_index::const_mem_fun<DBObject,VString,DBObject::getEntityName>>> ] xtyz.cpp . . . Build log was saved at "file://c:\code\win\Debug\obj\BuildLog.htm" ProjABC - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Thanks, Ram