Hi, BOOST_MULTI_INDEX_CONST_MEM_FUN is implemented ths way: #define BOOST_MULTI_INDEX_CONST_MEM_FUN(Class,Type,MemberFunName) \ ::boost::multi_index::const_mem_fun<Class,Type,&Class::MemberFunName> But when I need to do something like this: typedef boost::tuple<std::string, std::string> tuple; BOOST_MULTI_INDEX_CONST_MEM_FUN(tuple, std::string const&, get<0>); It doesnt work because of the two closing brackets that results from the macro expansion. Couldnt be added a space after &Class::MemberFunName ? Here it works ok adding the space. Thanks, -- Felipe Magno de Almeida