Orocos Real-Time Toolkit  2.8.3
NA.hpp
Go to the documentation of this file.
1 /***************************************************************************
2  tag: FMTC do nov 2 13:05:59 CET 2006 NA.hpp
3 
4  NA.hpp - description
5  -------------------
6  begin : do november 02 2006
7  copyright : (C) 2006 FMTC
8  email : peter.soetens@fmtc.be
9 
10  ***************************************************************************
11  * This library is free software; you can redistribute it and/or *
12  * modify it under the terms of the GNU General Public *
13  * License as published by the Free Software Foundation; *
14  * version 2 of the License. *
15  * *
16  * As a special exception, you may use this file as part of a free *
17  * software library without restriction. Specifically, if other files *
18  * instantiate templates or use macros or inline functions from this *
19  * file, or you compile this file and link it with other files to *
20  * produce an executable, this file does not by itself cause the *
21  * resulting executable to be covered by the GNU General Public *
22  * License. This exception does not however invalidate any other *
23  * reasons why the executable file might be covered by the GNU General *
24  * Public License. *
25  * *
26  * This library is distributed in the hope that it will be useful, *
27  * but WITHOUT ANY WARRANTY; without even the implied warranty of *
28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
29  * Lesser General Public License for more details. *
30  * *
31  * You should have received a copy of the GNU General Public *
32  * License along with this library; if not, write to the Free Software *
33  * Foundation, Inc., 59 Temple Place, *
34  * Suite 330, Boston, MA 02111-1307 USA *
35  * *
36  ***************************************************************************/
37 
38 
39 #ifndef ORO_NA_HPP
40 #define ORO_NA_HPP
41 
42 #include <boost/type_traits.hpp>
43 
44 namespace RTT
45 {
46  namespace internal
47  {
52  template<class T>
53  struct NA
54  {
55  public:
56  typedef typename boost::remove_const<typename boost::remove_reference<T>::type>::type value_type;
57  static T na() { return Gna; }
58  private:
59  static value_type Gna;
60  };
61 
65  template<>
66  struct NA<void>
67  {
68  typedef void value_type;
69  static void na() {};
70  };
71 
72  template<class T>
74  }
75 }
76 #endif
static T na()
Definition: NA.hpp:57
This class is used to return a &#39;default&#39; value when no value is available (&#39;Not Available&#39;).
Definition: NA.hpp:53
boost::remove_const< typename boost::remove_reference< T >::type >::type value_type
Definition: NA.hpp:56
Contains TaskContext, Activity, OperationCaller, Operation, Property, InputPort, OutputPort, Attribute.
Definition: Activity.cpp:51
static void na()
Definition: NA.hpp:69