Dear list, I need to keep track of two special vertices in my graph, So I thought to attach two vertex_descriptor as graph properties so have easy access any moment. Properties work fine for edges or vertices, but I cannot make them work for the graph. In the bottom is the C++ code. The graph has the two properties, now how I cat get and put them? This code does not work and the error messages are impossible to read for me. Otherwise that is the way to keep graph-wise properties? The code compiles removing the two puts, so I assume the error is there. Yours sincerely, Paolo #include <boost/graph/adjacency_list.hpp> namespace boost { enum graph_source_t { graph_source = 100 }; BOOST_INSTALL_PROPERTY (graph, source); enum graph_destination_t { graph_destination = 101 }; BOOST_INSTALL_PROPERTY (graph, destination); } typedef size_t graph_vertex; typedef boost::adjacency_list < boost::vecS, boost::vecS, boost::undirectedS, boost::no_property, boost::no_property, boost::property < boost::graph_source_t, graph_vertex, boost::property < boost::graph_destination_t, graph_vertex, boost::no_property>>> graph_t; static_assert(std::is_same<graph_vertex, boost::graph_traits<graph_t>::vertex_descriptor>::value, "Check out the vertex descriptor type!"); int main() { using namespace boost; graph_t g; add_edge(0, 1, g); put(graph_destination, g, 0); put(graph_source, g, 1); }