Hi, I'm new to Boost, and hope you can help me. When the attached source file is compiled with: gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-47.fc4) or gcc version 3.3.6 (Ubuntu 1:3.3.6-13ubuntu2) or gcc version 4.0.4 20060630 (prerelease) (Ubuntu 4.0.3-4), then running the program gives a segfault on line 27. When compiled with: gcc version 4.0.2 20051125 (Red Hat 4.0.2-8), no error occurs. To my understanding, no error should occur: I am using "listS" for both edges and vertices in adjacency_list. According to the documentation, clear_vertex() should not invalidate the adjacency_iterator in this case. However, in my code that's exactly what happens. I call adjacent_vertices() on a vertex A, which gives me an adjacency_iterator. Then I remove all edges from A by calling clear_vertex(). Then I want to use the adjacency_iterator obtained previously to check the new degrees of all (previous) neighbours of the removed vertex v. But the program crashes with a segmentation fault, when I try to use the iterator. Has anyone experienced this before? Is that a bug of the library? Cheers, Silvia -------------------------------------------------------------------------- This email and any attachments may be confidential. They may contain legally privileged information or copyright material. You should not read, copy, use or disclose them without authorisation. If you are not an intended recipient, please contact us at once by return email and then delete both messages. We do not accept liability in connection with computer virus, data corruption, delay, interruption, unauthorised access or unauthorised amendment. This notice should not be removed.