promotiontraits.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_PROMOTIONTRAITS_HH
#define DUNE_PROMOTIONTRAITS_HH
 
#include <utility>
 
namespace Dune {
  template <typename T1, typename T2>
  struct PromotionTraits
  {
    typedef decltype(std::declval<T1>()+std::declval<T2>()) PromotedType;
  };
 
  // Specialization for the case of two equal types
  // One should think that the generic template should handle this case as well.
  // However, the fvectortest.cc unit test fails without it if ENABLE_GMP is set.
  template <typename T1>
  struct PromotionTraits<T1,T1> { typedef T1 PromotedType; };
 
} // end namespace
 
 
#endif // DUNE_PROMOTIONTRAITS_HH