In Boost.Foreach docs, the user is informed about the possibility to do #define foreach BOOST_FOREACH so as to improve readability, provided there's no collisions in her code with the name 'foreach'. I think this advise is extremely unfortunate, because the collision happens right within Boost.Foreach code itself, as it uses the namespace boost::foreach internally. This results in problems like the one described in http://lists.boost.org/boost-users/2011/11/71762.php I think the only viable fix is to rename boost::foreach as boost::foreach_ or something and assume backwards incompatibility (as for Boost.MultiIndex, I'd have no problem in syncing up), unless someone figures out a smarter workaround. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo