Hi! First of all, I'd like to thank Matz for his patience in answering my silly questions. (My list class works fine now). The main purpose of practicing writing extensions was to gain enough experience to write an extension interface generator, which makes this not too complicated task even simpler. Hopefully, swig makes this unnecessary... But, back to my topic: Has anybody tried to compile ruby for 64-bits? Do I have to expect specific problems? Thanks a lot, Christian Szegedy