Visual Age 6.0 for AIX complains about the way list iterator is defined "/home/tk/boost_regression/boost/boost/mpl/list/aux_/iterator.hpp", line 30.47: 1540-0416 (S) "next" cannot be declared because its name has already been used. The offending line is typedef l_iter<typename next<Node>::type> next; I guess it'd suffice with rewriting it as: typedef l_iter<typename boost::mpl::next<Node>::type> next; This error (and similar ones in range_c, transform_view, joint_view, pair_view,filter_view) seem to share the same pattern: the compiler complains whenever it finds a structure like this: struct foo { ... name ... typedef ... name; }; a possible workaround (though I cannot test it) is to rewrite this as: struct foo { ... boost::mpl::name ... typedef ... name; }; I don't know if vacpp is meant to be supported by MPL. In case it is, maybe this can be of some help. Best, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo