Problem: transitive_closure.hpp won't compile if depth_first_search.hpp is included before including transitive_closure.hpp . This problem occurs when compiling with gcc 4.1.1. This problem does not occur with gcc 3.3.5 To reproduce: Edit example/transitive_closure.cpp and add: #include <boost/graph/depth_first_search.hpp> before #include <boost/graph/transitive_closure.hpp> Thanks, -TAG