Lumiera  0.pre.03
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null-value.hpp
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1 /*
2  NULL-VALUE.hpp - maintain per-type NIL values in static memory
3 
4  Copyright (C) Lumiera.org
5  2010, Hermann Vosseler <Ichthyostega@web.de>
6 
7  This program is free software; you can redistribute it and/or
8  modify it under the terms of the GNU General Public License as
9  published by the Free Software Foundation; either version 2 of
10  the License, or (at your option) any later version.
11 
12  This program is distributed in the hope that it will be useful,
13  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  GNU General Public License for more details.
16 
17  You should have received a copy of the GNU General Public License
18  along with this program; if not, write to the Free Software
19  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 
21 */
22 
23 
58 #ifndef LIB_NULL_VALUE_H
59 #define LIB_NULL_VALUE_H
60 
61 
62 
63 namespace lib {
64 
70  template<class TY>
71  struct NullValue
72  {
73  static TY const&
74  get()
75  {
76  static TY nilValue;
77  return nilValue;
78  }
79  };
80 
81 
82 
83 } // namespace lib
84 #endif
Singleton holder for NIL or default value objects.
Definition: null-value.hpp:71
Implementation namespace for support and library code.