I have a graph that I am having difficulty making a graph visitor. I thought a breadth first visitor would do but there is a issue of order. I cannot guarantee what the order of visits to all the vertices will be on a graph. My graph that I am testing against is a directed graph of Component objects. Each Component requires input from the parent Component objects in the graph. For example, (Graph) C1 | ------------------ | | | | C20 C30 C40 | | | | | ------------------- | C5 (Table of inputs) C1 C20 C30 C40 C5 C1 C20 x C30 x C40 x C5 x x x x x I thought a breadth first search visitor would work. The behavior I was expecting was visits in the following order: C1, C20, C30, C40, Cc5. What I found was that I had C1, C40 and then C5. My program will abort at that point that c5 is visited since it is missing inputs from C20 and C30. When I take away calls to my code in the visitor and include just a simple "Hey I am at Component X" message I get the order I suspect. My graph is defined as: typedef property< vertex_index_t, uint32_t, property< vertex_name_t, boost::shared_ptr<Component> > > VertexProperty_t; typedef adjacency_list<setS, // OutEdgeList setS, // VertexList directedS, // Directed VertexProperty_t> // VertexProperties Graph_t; The visitor is defined as: class Graph_Visitor : public boost::default_bfs_visitor { public: // Constructor Graph_Visitor ( infrastructure::Component_Graph const& graph_ref, infrastructure::Graph_Base::Data_Map_t* dmap ); // Visitor functions template <class Vertex, class Graph> void discover_vertex(Vertex v, Graph const& g) { boost::shared_ptr<infrastructure::Component> src_obj_ptr = m_graph_ref.get_Component(v); std::cout << "Visiting node: " << src_obj_ptr->get_ID() << std::endl; .... verify inputs .... .... if all inputs present then do work .... } }; Is there a problem with my choice of design for the graph or how I am using the breadth first visitor? Stephen