Hi Guys, I am using boost graph library in my research project about graph theory. One object is testing whether graph G1 has a subgraph isomorphic to another graph G2. I only care about the result, "yes" or "no", and don't expected to find out a isomorphism pattern. I use the library function vf2_subgraph_iso(), but the third parameter is a callback function which will print out the isomorphic pattern all the time. Is there any way to omit this parameter or eliminate the output pattern. Here is my code snippet: ----------------------------------------------------- vf2_print_callback callback(C4, g); if (!vf2_subgraph_iso(C4, g, callback) { // something; } else { // something; } __________________________________ Thanks for you attention! Best Regards! Shouwei