>>>>> "B" == Benoit Cerrina <benoit.cerrina / writeme.com> writes: B> C extension. I couldn't find a way to do it although I think it would be B> doable by B> evaling some ruby but I'd like to know if there is a c call appropriate. Well, you can write something like this VALUE arity = rb_funcall2(rb_funcall2(self, rb_intern("method"), 1, &id), rb_intern("arity"), 0, 0); I don't know if it exist another way to do it. Guy Decoux