VC动态加载DLL怎么区分相同参数列表和返回类型的函数

///函数调用定义,函数参数类型,返回类型应该与dll中一致
 typedef DWORD (_stdcall MYDLLFUN)(DWORD nPort, DWORD nBaudrate, LPTSTR  dir);
//函数指针声明

static HINSTANCE hmydll;

 static MYDLLFUN *mydllfun;
void initCommDll()
{
   hmydll=::LoadLibrary("mydll.DLL");
   VERIFY(mydllfun=(MYDLLFUN *)::GetProcAddress(hmydll,"mydllfun"));
}