Hello. Is the function graph_traits<G>::null_vertex() defined for G = filtered_graph? When I try to compile the following simple program: -------------------------------------------------------------- #include <boost/graph/adjacency_list.hpp> #include <boost/graph/filtered_graph.hpp> using namespace boost; int main() { typedef adjacency_list<vecS> graph_t; typedef filtered_graph<graph_t,keep_all> f_graph_t; graph_traits<f_graph_t>::vertex_descriptor v = graph_traits<f_graph_t>::null_vertex(); return 0; } -------------------------------------------------------------- I get the following error with GCC 4.0.1 and boost 1.33.0: /usr/include/boost/graph/graph_traits.hpp: In static member function ‘static typename boost::graph_traits<G>::vertex_descriptor boost::graph_traits<G>::null_vertex() [with G = main()::f_graph_t]’: filtered_test.cc:10: instantiated from here /usr/include/boost/graph/graph_traits.hpp:49: error: ‘null_vertex’ is not a member of ‘main()::f_graph_t’ Shouldn't null_vertex() just be defined to return the null_vertex() for the underlying graph, since the vertex descriptors are the same? Do I miss something? -- Tiago de Paula Peixoto <tiago@forked.de>