| |
| // (C) Copyright John Maddock 2017. |
| // Use, modification and distribution are subject to the Boost Software License, |
| // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt). |
| // |
| // See http://www.boost.org/libs/type_traits for most recent version including documentation. |
| |
| #ifndef BOOST_TT_IS_COMPLETE_HPP_INCLUDED |
| #define BOOST_TT_IS_COMPLETE_HPP_INCLUDED |
| |
| #include <boost/type_traits/declval.hpp> |
| #include <boost/type_traits/integral_constant.hpp> |
| #include <boost/type_traits/remove_reference.hpp> |
| #include <boost/type_traits/is_function.hpp> |
| #include <boost/type_traits/detail/yes_no_type.hpp> |
| #include <boost/config/workaround.hpp> |
| |
| /* |
| * CAUTION: |
| * ~~~~~~~~ |
| * |
| * THIS TRAIT EXISTS SOLELY TO GENERATE HARD ERRORS WHEN A ANOTHER TRAIT |
| * WHICH REQUIRES COMPLETE TYPES AS ARGUMENTS IS PASSED AN INCOMPLETE TYPE |
| * |
| * DO NOT MAKE GENERAL USE OF THIS TRAIT, AS THE COMPLETENESS OF A TYPE |
| * VARIES ACROSS TRANSLATION UNITS AS WELL AS WITHIN A SINGLE UNIT. |
| * |
| */ |
| |
| namespace boost { |
| |
| |
| // |
| // We will undef this if the trait isn't fully functional: |
| // |
| #define BOOST_TT_HAS_WORKING_IS_COMPLETE |
| |
| #if !defined(BOOST_NO_SFINAE_EXPR) && !BOOST_WORKAROUND(BOOST_MSVC, <= 1900) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40600) |
| |
| namespace detail{ |
| |
| template <unsigned N> |
| struct ok_tag { double d; char c[N]; }; |
| |
| template <class T> |
| ok_tag<sizeof(T)> check_is_complete(int); |
| template <class T> |
| char check_is_complete(...); |
| } |
| |
| template <class T> struct is_complete |
| : public integral_constant<bool, ::boost::is_function<typename boost::remove_reference<T>::type>::value || (sizeof(boost::detail::check_is_complete<T>(0)) != sizeof(char))> {}; |
| |
| #elif !defined(BOOST_NO_SFINAE) && !defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40500) |
| |
| namespace detail |
| { |
| |
| template <class T> |
| struct is_complete_imp |
| { |
| template <class U, class = decltype(sizeof(boost::declval< U >())) > |
| static type_traits::yes_type check(U*); |
| |
| template <class U> |
| static type_traits::no_type check(...); |
| |
| static const bool value = sizeof(check<T>(0)) == sizeof(type_traits::yes_type); |
| }; |
| |
| } // namespace detail |
| |
| |
| template <class T> |
| struct is_complete : boost::integral_constant<bool, ::boost::is_function<typename boost::remove_reference<T>::type>::value || ::boost::detail::is_complete_imp<T>::value> |
| {}; |
| template <class T> |
| struct is_complete<T&> : boost::is_complete<T> {}; |
| |
| #else |
| |
| template <class T> struct is_complete |
| : public boost::integral_constant<bool, true> {}; |
| |
| #undef BOOST_TT_HAS_WORKING_IS_COMPLETE |
| |
| #endif |
| |
| } // namespace boost |
| |
| #endif // BOOST_TT_IS_COMPLETE_HPP_INCLUDED |