Eddie, Many thanks for the patches. I have now commited them to the ns-distribution and they should be visible in the daily snapshot at : http://mash.cs.berkeley.edu/dist/vint/ns-src-current.tar.gz and also in Tclcl. With these patches, ns now compiles succesfully with gcc versions 2.7.x (or higher, in particular 2.8.1) Sandeep.