Here it is. The problem was I didn't use makefiles generated by extconf.rb. The only thing I need to build my extension with MS CC or Intel's compiler was definition: #define NT=1 Just like it defined in makefiles. Since NT is defined macro EXTERN in ruby.h is rolled out correctly and rb_cObjects are the same. # -----Original Message----- # From: Aleksei Guzev [mailto:aleksei.guzev / bigfoot.com] # Sent: 29 ÉÀÎÑ 2001 ?. 12:13 # To: ruby-talk ML # Subject: [ruby-talk:17052] Problem building extension # # # # rb_cObject given to my extension by mswin32-ruby16.lib and # rb_cObject in Ruby itself are not the same. # # I did not investigate the problem at all. Does anyone know # what's wrong? #