Claw  1.7.0
is_base_of.hpp
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00001 /*
00002   CLAW - a C++ Library Absolutely Wonderful
00003 
00004   CLAW is a free library without any particular aim but being useful to 
00005   anyone.
00006 
00007   Copyright (C) 2005-2011 Julien Jorge
00008 
00009   This library is free software; you can redistribute it and/or
00010   modify it under the terms of the GNU Lesser General Public
00011   License as published by the Free Software Foundation; either
00012   version 2.1 of the License, or (at your option) any later version.
00013 
00014   This library is distributed in the hope that it will be useful,
00015   but WITHOUT ANY WARRANTY; without even the implied warranty of
00016   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017   Lesser General Public License for more details.
00018 
00019   You should have received a copy of the GNU Lesser General Public
00020   License along with this library; if not, write to the Free Software
00021   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00022 
00023   contact: julien.jorge@gamned.org
00024 */
00030 #ifndef __CLAW_IS_BASE_OF_HPP__
00031 #define __CLAW_IS_BASE_OF_HPP__
00032 
00033 namespace claw
00034 {
00035   namespace meta
00036   {
00048     template<typename Base, typename Derived>
00049     struct is_base_of
00050     {
00051     private:
00052       static Derived* m_d;
00053 
00054     private:
00055       static char check( Base* );
00056       static long check( ... );
00057 
00058     public:
00059       enum
00060   {
00061     result = ( sizeof(check( m_d )) == sizeof(char) )
00062   };
00063     }; // struct is_base_of [false]
00064 
00065   } // namespace meta
00066 } // namespace claw
00067 
00068 #endif // __CLAW_IS_BASE_OF_HPP__