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// common_type.hpp ---------------------------------------------------------//
// Copyright 2010 Vicente J. Botet Escriba
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
#ifndef NDNBOOST_TYPE_TRAITS_EXT_DECLVAL__HPP
#define NDNBOOST_TYPE_TRAITS_EXT_DECLVAL__HPP
#include <ndnboost/config.hpp>
//----------------------------------------------------------------------------//
#include <ndnboost/type_traits/add_rvalue_reference.hpp>
//#include <ndnboost/type_traits/add_lvalue_reference.hpp>
//----------------------------------------------------------------------------//
// //
// C++03 implementation of //
// Written by Vicente J. Botet Escriba //
//~ 20.3.4 Function template declval [declval]
//~ 1 The library provides the function template declval to simplify the definition of expressions which occur as
//~ unevaluated operands.
//~ 2 Remarks: If this function is used, the program is ill-formed.
//~ 3 Remarks: The template parameter T of declval may be an incomplete type.
//~ [ Example:
//~ template <class To, class From>
//~ decltype(static_cast<To>(declval<From>())) convert(From&&);
//~ declares a function template convert which only participats in overloading if the type From can be
//~ explicitly converted to type To. For another example see class template common_type (20.7.6.6). —end
//~ example ]
// //
//----------------------------------------------------------------------------//
namespace ndnboost {
//#if !defined(NDNBOOST_NO_RVALUE_REFERENCES)
template <typename T>
typename add_rvalue_reference<T>::type declval() NDNBOOST_NOEXCEPT; // as unevaluated operand
//#else
// template <typename T>
// typename add_lvalue_reference<T>::type declval() NDNBOOST_NOEXCEPT; // as unevaluated operand
//#endif
} // namespace ndnboost
#endif // NDNBOOST_TYPE_TRAITS_EXT_DECLVAL__HPP