# File lib/childprocess/tools/generator.rb, line 48
      def fetch_size(type_name, opts = {})
        print "sizeof(#{type_name}): "
        src = "int main() {\nprintf(\"%d\", (unsigned int)sizeof(\#{type_name}));\nreturn 0;\n}\n"

        output = execute(src, opts)

        if output.to_i < 1
          raise "sizeof(#{type_name}) == #{output.to_i} (output=#{output})"
        end

        size = output.to_i
        @sizeof[type_name] = size

        puts size
      end