调用Win32API时出错，请专家指点，谢谢！

ruby脚本：
require 'Win32API'
shell = Win32API.new("ruby_c_adpt_dll.dll", "print_msg", "PN", "N")

生成ruby_c_adpt_dll.dll的.c代码：
#include <stdio.h>
int print_msg(char* text, int number)
{
 return printf("Text: %s, (%d)\n", text, number);
}

运行脚本的时候出现的错误打印：
>ruby temp.rb
temp.rb:407:in `initialize': GetProcAddress: print_msg or print_msgA (RuntimeError)
    from temp.rb:407:in `new'
    from temp.rb:407
>Exit code: 1