From: Ryan Davis <ryand-ruby@...>
Date: 2007-03-26T03:31:28+09:00
Subject: Re: Ruby with C

Your question has already been answered. Alternatively, use inline to  
learn without all the hassle (no makefile, no builds, no type  
conversions, no time wasted). Just try out what you want to do  
straight up in ruby with inlined C, and then go look at what the C  
code is producing:

#!/usr/local/bin/ruby

require 'rubygems'
require 'inline'

class PKey
   inline do |builder|
     builder.c <<-EOM
       static void bit(int n) {
         printf("Fun %d\\n", n);
       }
     EOM
   end
end

k = PKey.new
k.bit(5)

############################################################
# Produces:
#
# #include "ruby.h"
#
# # line 9 "./blah.rb"
# static VALUE bit(VALUE self, VALUE _n) {
#   int n = FIX2INT(_n);
#
#         printf("Fun %d\n", n);
# return Qnil;
# }
#
# #ifdef __cplusplus
# extern "C" {
# #endif
#   void Init_Inline_PKey_f671() {
#     VALUE c = rb_cObject;
#     c = rb_const_get_at(c,rb_intern("PKey"));
#     rb_define_method(c, "bit", (VALUE(*)(ANYARGS))bit, 1);
#
#   }
# #ifdef __cplusplus
# }
# #endif