Well, it turns out that I made a small mistake: //Class template of a vertex/edge property writer template < typename Graph > class property_writer { public: property_writer(Graph _g) : g(_g) {} template <typename Vertex_or_Edge> void operator()(std::ostream& out, const Vertex_or_Edge& v) { out << "[label=\"" << g[v].toString() << "\"]"; } private: Graph& g; }; Changing the argument of property_writer from "Graph _g" to be "Graph& _g" solves this. I started the property writer from the example in BGL documenation: boost_1_32_0/libs/graph/doc/write-graphviz.html, so I suggest changing this doc to be more efficient. _____ From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Welson Sun Sent: Wednesday, February 16, 2005 1:43 PM To: boost-users@lists.boost.org Subject: [Boost-users] Program runs OK in Cygwin,but got "Segment Fault" in Linux Hi, The program is really simple, it creates a graph and output to a .dot file using the graphviz library in the BGL. It runs well in Cygwin, but in Linux, it got a segment fault when outputing the vertex id. Can you C++ gurus see what is going on? Thanks! Welson