| // 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 BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP |
| #define BOOST_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(BOOST_NO_RVALUE_REFERENCES) |
| template <typename T> |
| typename add_rvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand |
| //#else |
| // template <typename T> |
| // typename add_lvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand |
| //#endif |
| } // namespace ndnboost |
| |
| #endif // BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP |