Orocos Real-Time Toolkit  2.5.0
NA.hpp
00001 /***************************************************************************
00002   tag: FMTC  do nov 2 13:05:59 CET 2006  NA.hpp
00003 
00004                         NA.hpp -  description
00005                            -------------------
00006     begin                : do november 02 2006
00007     copyright            : (C) 2006 FMTC
00008     email                : peter.soetens@fmtc.be
00009 
00010  ***************************************************************************
00011  *   This library is free software; you can redistribute it and/or         *
00012  *   modify it under the terms of the GNU General Public                   *
00013  *   License as published by the Free Software Foundation;                 *
00014  *   version 2 of the License.                                             *
00015  *                                                                         *
00016  *   As a special exception, you may use this file as part of a free       *
00017  *   software library without restriction.  Specifically, if other files   *
00018  *   instantiate templates or use macros or inline functions from this     *
00019  *   file, or you compile this file and link it with other files to        *
00020  *   produce an executable, this file does not by itself cause the         *
00021  *   resulting executable to be covered by the GNU General Public          *
00022  *   License.  This exception does not however invalidate any other        *
00023  *   reasons why the executable file might be covered by the GNU General   *
00024  *   Public License.                                                       *
00025  *                                                                         *
00026  *   This library is distributed in the hope that it will be useful,       *
00027  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
00028  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
00029  *   Lesser General Public License for more details.                       *
00030  *                                                                         *
00031  *   You should have received a copy of the GNU General Public             *
00032  *   License along with this library; if not, write to the Free Software   *
00033  *   Foundation, Inc., 59 Temple Place,                                    *
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00035  *                                                                         *
00036  ***************************************************************************/
00037 
00038 
00039 #ifndef ORO_NA_HPP
00040 #define ORO_NA_HPP
00041 
00042 #include <boost/type_traits.hpp>
00043 
00044 namespace RTT
00045 {
00046     namespace internal
00047     {
00052         template<class T>
00053         struct NA
00054         {
00055         public:
00056             typedef typename boost::remove_const<typename boost::remove_reference<T>::type>::type value_type;
00057             static T na() { return Gna; }
00058         private:
00059             static value_type Gna;
00060         };
00061 
00065         template<>
00066         struct NA<void>
00067         {
00068             typedef void value_type;
00069             static void na() {};
00070         };
00071 
00072         template<class T>
00073         typename NA<T>::value_type NA<T>::Gna;
00074     }
00075 }
00076 #endif