Hi all, I'm currently trying to write a wrapper in order to use the BGL algorithms and visitors on a home-made graph class. If I'm not mistaken, this requires me to write (amongst other things) a couple functions that will return iterators over my graph edges and vertices, eg: std::pair<graph_traits<MyGraph>::out_edge_iterator, graph_traits<MyGraph>::out_edge_iterator > out_edges(graph_traits<MyGraph>::vertex_descriptor u, const MyGraph& g) and similarly in_edges(...) , vertices(...) and edges(...) functions. However, it seems that this function profile forces me to do a const_cast on g when implementing the function body since the out_edge_iterators are not const iterators, though they point to internal elements of g. I had a look at the example given in the documentation (dealing with converting LEDA graphs to the BGL), but I didn't see anything helping me on this particular issue (also, the example in the doc is a bit outdated since it uses the deprecated Boost iterator adaptors). Am I forced to rely on const_cast in these functions, or is there a way to declare my graph edges, vertices and the corresponding iterators as const in my graph_traits class ? I'm a newbie with the BGL, and more generally with this whole traits/template specialization style of programming, so please excuse me if I overlooked something obvious. Cheers.