nulltype.h

来自「loki 程序库」· C头文件 代码 · 共 40 行

////////////////////////////////////////////////////////////////////////////////
// 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-Wesley 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: November 22, 2001

#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 {};
    
}   // namespace Loki

////////////////////////////////////////////////////////////////////////////////
// Change log:
// June 20, 2001: ported by Nick Thurn to gcc 2.95.3. Kudos, Nick!!!
// November 22, 2001: minor change to support porting to boost
////////////////////////////////////////////////////////////////////////////////

#endif // NULLTYPE_INC_