In function: void clean_data (MyMap& map) { remove_if(map.begin(), map.end(), (&lambda::_1 )->*(&pair< X* const, double >::second) <= m_epsilon); } where: typedef std::map MyMap; I get error: c:\program files\microsoft visual studio 9.0\vc\include\algorithm(1240) : error C2582: 'operator =' function is unavailable in 'std::pair<_Ty1,_Ty2>' with [ _Ty1=const hapl::Haplotype *const , _Ty2=double ] c:\program files\microsoft visual studio 9.0\vc\include\algorithm(4949) : see reference to function template instantiation '_OutIt std::_Remove_copy_if::iterator,_OutIt,_Pr>(_InIt,_InIt,_OutIt,_Pr,std::_Range_checked_iterator_tag)' being compiled with [ _OutIt=std::_Tree,std::allocator>,false>>::iterator, _Traits=std::_Tmap_traits,std::allocator>,false>, _Pr=boost::lambda::lambda_functorboost::lambda::lessorequal_action,boost::tuples::tupleboost::lambda::member_pointer_action>,boost::tuples::tupleboost::lambda::addressof_action,boost::tuples::tuple>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,double std::pair::* const ,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,const double,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>, _InIt=std::_Tree,std::allocator>,false>>::iterator ] c:\program files\microsoft visual studio 9.0\vc\include\algorithm(1309) : see reference to function template instantiation '_OutIt stdext::unchecked_remove_copy_if::iterator,_FwdIt,_Pr>(_InIt,_InIt,_OutIt,_Pr)' being compiled with [ _OutIt=std::_Tree,std::allocator>,false>>::iterator, _Traits=std::_Tmap_traits,std::allocator>,false>, _FwdIt=std::_Tree,std::allocator>,false>>::iterator, _Pr=boost::lambda::lambda_functorboost::lambda::lessorequal_action,boost::tuples::tupleboost::lambda::member_pointer_action>,boost::tuples::tupleboost::lambda::addressof_action,boost::tuples::tuple>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,double std::pair::* const ,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,const double,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>, _InIt=std::_Tree,std::allocator>,false>>::iterator ] c:\users\kott\documents\visual studio 2008\projects\mbi\implementation\src\main.cpp(631) : see reference to function template instantiation '_FwdIt std::remove_if::iterator,boost::lambda::lambda_functor<T>>(_FwdIt,_FwdIt,_Pr)' being compiled with [ _FwdIt=std::_Tree,std::allocator>,false>>::iterator, _Traits=std::_Tmap_traits,std::allocator>,false>, T=boost::lambda::lambda_functor_baseboost::lambda::lessorequal_action,boost::tuples::tupleboost::lambda::member_pointer_action>,boost::tuples::tupleboost::lambda::addressof_action,boost::tuples::tuple>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,double std::pair::* const ,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,const double,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>, _Pr=boost::lambda::lambda_functorboost::lambda::lessorequal_action,boost::tuples::tupleboost::lambda::member_pointer_action>,boost::tuples::tupleboost::lambda::addressof_action,boost::tuples::tuple>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,double std::pair::* const ,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>>,const double,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>>> ] I don't get it because i found somewhere (http://www.lukaszczerwinski.pl/boost_lambda_member_access.html) similar example that (should) work fine: std::map< std::string , int > someMap; using boost::lambda::_1; std::for_each( someMap.begin(), someMap.end(), std::cout << ( & _1 ) ->* ( & std::pair< std::string const, int >::first ) << std::endl ); -- Michał Nowotka