libstdc++-v3/include/tr1/common.h

   1 // Internal header for TR1 complex -*- C++ -*-
   2
   3 // Copyright (C) 2006 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /** @file
  31  *  This is a TR1 C++ Library header.
  32  */
  33
  34 #ifndef _TR1_COMMON_H
  35 #define _TR1_COMMON_H 1
  36
  37 #include <tr1/type_traits>
  38
  39 // namespace std::tr1
  40 namespace std
  41 {
  42 _GLIBCXX_BEGIN_NAMESPACE(tr1)
  43
  44   template<typename _Tp, bool = is_integral<_Tp>::value>
  45     struct __promote
  46     { typedef double __type; };
  47
  48   template<typename _Tp>
  49     struct __promote<_Tp, false>
  50     { typedef _Tp __type; };
  51
  52   template<typename _Tp, typename _Up>
  53     struct __promote_2
  54     {
  55     private:
  56       typedef typename __promote<_Tp>::__type __type1;
  57       typedef typename __promote<_Up>::__type __type2;
  58
  59     public:
  60       typedef __typeof__(__type1() + __type2()) __type;
  61     };
  62
  63 _GLIBCXX_END_NAMESPACE
  64 } // namespace std
  65
  66 #endif