I created a gem for a ruby C extension. Compiling the gem and installation goes find. When I try to run the test I get the following error: [gus@comp ~]$ sudo ruby /usr/lib/ruby/gems/1.8/gems/Rulog-0.1.0/test/rulog.rb Loaded suite /usr/lib/ruby/gems/1.8/gems/Rulog-0.1.0/test/rulog Started .ruby: symbol lookup error: /usr/lib/ruby/gems/1.8/gems/Rulog-0.1.0/lib/rulog.so: undefined symbol: rb_mark But, if I specify an include directory to ruby, it work: [gus@comp ~]$ sudo ruby -I /usr/lib/ruby/gems/1.8/gems/Rulog-0.1.0/lib /usr/lib/ruby/gems/1.8/gems/Rulog-0.1.0/test/rulog.rb Loaded suite /usr/lib/ruby/gems/1.8/gems/Rulog-0.1.0/test/rulog Started .... Finished in 2.341459 seconds. 4 tests, 38 assertions, 0 failures, 0 errors Duh! Why can't it load rulog.so in the first case? The platform is ruby 1.8.2 (2004-12-25) [i586-linux-gnu]. Any idea, pointers? Guillaume.