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- // (C) Copyright Ion Gaztanaga 2014.
- //
- // 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_COPY_ASSIGNABLE_HPP_INCLUDED
- #define BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED
- #include <boost/config.hpp>
- #include <boost/type_traits/detail/yes_no_type.hpp>
- #include <boost/type_traits/is_noncopyable.hpp>
- #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_NO_CXX11_DECLTYPE) \
- && !defined(BOOST_INTEL_CXX_VERSION) && \
- !(defined(BOOST_MSVC) && _MSC_VER == 1800)
- #define BOOST_TT_CXX11_IS_COPY_ASSIGNABLE
- #include <boost/type_traits/declval.hpp>
- #else
- //For compilers without decltype
- #include <boost/type_traits/is_const.hpp>
- #include <boost/type_traits/is_array.hpp>
- #include <boost/type_traits/add_reference.hpp>
- #include <boost/type_traits/remove_reference.hpp>
- #endif
- namespace boost {
- namespace detail{
- template <bool DerivedFromNoncopyable, class T>
- struct is_copy_assignable_impl2 {
- // Intel compiler has problems with SFINAE for copy constructors and deleted functions:
- //
- // error: function *function_name* cannot be referenced -- it is a deleted function
- // static boost::type_traits::yes_type test(T1&, decltype(T1(boost::declval<T1&>()))* = 0);
- // ^
- //
- // MSVC 12.0 (Visual 2013) has problems when the copy constructor has been deleted. See:
- // https://connect.microsoft.com/VisualStudio/feedback/details/800328/std-is-copy-constructible-is-broken
- #if defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE)
- typedef boost::type_traits::yes_type yes_type;
- typedef boost::type_traits::no_type no_type;
- template <class U>
- static decltype(::boost::declval<U&>() = ::boost::declval<const U&>(), yes_type() ) test(int);
- template <class>
- static no_type test(...);
- static const bool value = sizeof(test<T>(0)) == sizeof(yes_type);
- #else
- static BOOST_DEDUCED_TYPENAME boost::add_reference<T>::type produce();
- template <class T1>
- static boost::type_traits::no_type test(T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0);
- static boost::type_traits::yes_type test(...);
- // If you see errors like this:
- //
- // `'T::operator=(const T&)' is private`
- // `boost/type_traits/is_copy_assignable.hpp:NN:M: error: within this context`
- //
- // then you are trying to call that macro for a structure defined like that:
- //
- // struct T {
- // ...
- // private:
- // T & operator=(const T &);
- // ...
- // };
- //
- // To fix that you must modify your structure:
- //
- // // C++03 and C++11 version
- // struct T: private boost::noncopyable {
- // ...
- // private:
- // T & operator=(const T &);
- // ...
- // };
- //
- // // C++11 version
- // struct T {
- // ...
- // private:
- // T& operator=(const T &) = delete;
- // ...
- // };
- BOOST_STATIC_CONSTANT(bool, value = (
- sizeof(test(produce())) == sizeof(boost::type_traits::yes_type)
- ));
- #endif
- };
- template <class T>
- struct is_copy_assignable_impl2<true, T> {
- BOOST_STATIC_CONSTANT(bool, value = false);
- };
- template <class T>
- struct is_copy_assignable_impl {
- #if !defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE)
- //For compilers without decltype, at least return false on const types, arrays
- //types derived from boost::noncopyable and types defined as BOOST_MOVEABLE_BUT_NOT_COPYABLE
- typedef BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type unreferenced_t;
- BOOST_STATIC_CONSTANT(bool, value = (
- boost::detail::is_copy_assignable_impl2<
- boost::is_noncopyable<T>::value
- || boost::is_const<unreferenced_t>::value || boost::is_array<unreferenced_t>::value
- ,T
- >::value
- ));
- #else
- BOOST_STATIC_CONSTANT(bool, value = (
- boost::detail::is_copy_assignable_impl2<
- boost::is_noncopyable<T>::value,T
- >::value
- ));
- #endif
- };
- } // namespace detail
- template <class T> struct is_copy_assignable : public integral_constant<bool, ::boost::detail::is_copy_assignable_impl<T>::value>{};
- template <> struct is_copy_assignable<void> : public false_type{};
- #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
- template <> struct is_copy_assignable<void const> : public false_type{};
- template <> struct is_copy_assignable<void const volatile> : public false_type{};
- template <> struct is_copy_assignable<void volatile> : public false_type{};
- #endif
- } // namespace boost
- #endif // BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED
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