Has anybody created custom dijkstra_shortest_paths algorithm visitor for discover_vertex event? I am having all sorts of compilation errors using MSVC 7.1 and defining my visitor using example code. Reshuffling the code (but at this point I hardly know what am I really doing) I got the following to compile: // define visitor for discover_vertex event template <class Vertex, class Tag> struct target_visitor : public default_dijkstra_visitor { target_visitor(Vertex u) : v(u) { } template <class Vertex, class Graph> void discover_vertex(Vertex u, Graph& g) { if ( u==v ) assert(0); } private: Vertex v; }; template <class Vertex, class Tag> target_visitor<Vertex, Tag> target_visit(Vertex u, Tag) { return target_visitor<Vertex, Tag>(u); } ... // call dijkstra_shortest_paths with custom visitor // parameters below are defined as in dijkstra-example.cpp dijkstra_shortest_paths(g, s, predecessor_map(&p[0]).distance_map(&d[0]).visitor(target_visit(D, on_discover_vertex()))); Tony Confused