www.pudn.com > Loki.rar > NullType.h

//////////////////////////////////////////////////////////////////////////////// 
// The Loki Library 
// Copyright (c) 2001 by Andrei Alexandrescu 
// This code accompanies the book: 
// Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design  
//     Patterns Applied". Copyright (c) 2001. Addison-Wesley. 
// Permission to use, copy, modify, distribute and sell this software for any  
//     purpose is hereby granted without fee, provided that the above copyright  
//     notice appear in all copies and that both that copyright notice and this  
//     permission notice appear in supporting documentation. 
// The author or Addison-Welsey Longman make no representations about the  
//     suitability of this software for any purpose. It is provided "as is"  
//     without express or implied warranty. 
//////////////////////////////////////////////////////////////////////////////// 
 
// Last update: May 19, 2002 
 
#ifndef NULLTYPE_INC_ 
#define NULLTYPE_INC_ 
 
namespace Loki 
{ 
//////////////////////////////////////////////////////////////////////////////// 
// class NullType 
// Used as a placeholder for "no type here" 
// Useful as an end marker in typelists  
//////////////////////////////////////////////////////////////////////////////// 
 
    class NullType  
    { 
    public: 
        struct Head { private: Head(); }; 
        struct Tail { private: Tail(); }; 
    }; 
} 
 
/////////////////////////////////////////////////////////////////////////////// 
// Change log: 
// June 20, 2001: ported by Nick Thurn to gcc 2.95.3. Kudos, Nick!!! 
// May  10, 2002: ported by Rani Sharoni to VC7 (RTM - 9466) 
//////////////////////////////////////////////////////////////////////////////// 
 
#endif // NULLTYPE_INC_