程序代码：

#include "windows.h"
#include "winsock2.h"
int WSA_return;
WSADATA       wSAData;
HOSTENT  *host_entry;
char host_name[256];
char host_address[256];

APIENTRY int WinMain(HINSTANCE hIstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)
{
   WSA_return=WSAStartup(0x0101,&wSAData);
   if(WSA_return==0)
   {
      gethostname(host_name,256);
      host_entry=gethostbyname(host_name);
      if(host_entry!=0)
      {
        wsprintf(host_address,"%d.%d.%d.%d",
        (host_entry->h_addr_list[0][0]&0x00ff),
        (host_entry->h_addr_list[0][1]&0x00ff),
        (host_entry->h_addr_list[0][2]&0x00ff),
        (host_entry->h_addr_list[0][3]&0x00ff)
        );
        MessageBox(NULL,host_address,host_name,MB_OK);
      }
   }
   WSACleanup();
   return 0;
}


我用C-Free 5.0 写的，编译后出现了错误
--------------------配置: mingw5 - GUI Debug, 编译器类型: MinGW--------------------

检查文件依赖性...
正在编译 C:\Users\hp\Documents\C-Free\Temp\未命名1.cpp...
[Warning] C:\Users\hp\Documents\C-Free\Temp\未命名1.cpp:29:2: warning: no newline at end of file
正在连接...
[Error] C:\Users\hp\Documents\C-Free\Temp\未命名1.cpp:11: undefined reference to `WSAStartup@8'
[Error] C:\Users\hp\Documents\C-Free\Temp\未命名1.cpp:14: undefined reference to `gethostname@8'
[Error] C:\Users\hp\Documents\C-Free\Temp\未命名1.cpp:15: undefined reference to `gethostbyname@4'
[Error] C:\Users\hp\Documents\C-Free\Temp\未命名1.cpp:27: undefined reference to `WSACleanup@0'
[Error] collect2: ld returned 1 exit status

构建中止 未命名1: 5 个错误, 1 个警告

这该怎么办啊？请教高手……