boost/type_traits/is_copy_constructible.hpp
// (C) Copyright Antony Polukhin 2013.
//
// 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_CONSTRUCTIBLE_HPP_INCLUDED
#define BOOST_TT_IS_COPY_CONSTRUCTIBLE_HPP_INCLUDED
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40900)
#include <boost/type_traits/is_constructible.hpp>
#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1800)
namespace boost {
template <class T> struct is_copy_constructible : public boost::is_constructible<T, const T&>{};
template <> struct is_copy_constructible<void> : public false_type{};
template <> struct is_copy_constructible<void const> : public false_type{};
template <> struct is_copy_constructible<void const volatile> : public false_type{};
template <> struct is_copy_constructible<void volatile> : public false_type{};
} // namespace boost
#else
//
// Special version for VC12 which has a problem when a base class (such as non_copyable) has a deleted
// copy constructor. In this case the compiler thinks there really is a copy-constructor and tries to
// instantiate the deleted member. std::is_copy_constructible has the same issue (or at least returns
// an incorrect value, which just defers the issue into the users code) as well. We can at least fix
// boost::non_copyable as a base class as a special case:
//
#include <boost/type_traits/is_noncopyable.hpp>
namespace boost {
namespace detail
{
template <class T, bool b> struct is_copy_constructible_imp : public boost::is_constructible<T, const T&>{};
template <class T> struct is_copy_constructible_imp<T, true> : public false_type{};
}
template <class T> struct is_copy_constructible : public detail::is_copy_constructible_imp<T, is_noncopyable<T>::value>{};
template <> struct is_copy_constructible<void> : public false_type{};
template <> struct is_copy_constructible<void const> : public false_type{};
template <> struct is_copy_constructible<void const volatile> : public false_type{};
template <> struct is_copy_constructible<void volatile> : public false_type{};
} // namespace boost
#endif
#else
#include <boost/type_traits/detail/yes_no_type.hpp>
#include <boost/type_traits/is_noncopyable.hpp>
#include <boost/type_traits/add_reference.hpp>
#include <boost/type_traits/is_rvalue_reference.hpp>
#include <boost/type_traits/declval.hpp>
#include <boost/type_traits/is_array.hpp>
#include <boost/type_traits/declval.hpp>
#ifdef BOOST_MSVC
#pragma warning(push)
#pragma warning(disable:4181)
#endif
namespace boost {
namespace detail{
template <bool DerivedFromNoncopyable, class T>
struct is_copy_constructible_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_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_INTEL_CXX_VERSION) && !(defined(BOOST_MSVC) && _MSC_VER == 1800)
#ifdef BOOST_NO_CXX11_DECLTYPE
template <class T1>
static boost::type_traits::yes_type test(const T1&, boost::mpl::int_<sizeof(T1(boost::declval<const T1&>()))>* = 0);
#else
template <class T1>
static boost::type_traits::yes_type test(const T1&, decltype(T1(boost::declval<const T1&>()))* = 0);
#endif
static boost::type_traits::no_type test(...);
#else
template <class T1>
static boost::type_traits::no_type test(const T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0);
static boost::type_traits::yes_type test(...);
#endif
// If you see errors like this:
//
// `'T::T(const T&)' is private`
// `boost/type_traits/is_copy_constructible.hpp:68:5: error: within this context`
//
// then you are trying to call that macro for a structure defined like that:
//
// struct T {
// ...
// private:
// T(const T &);
// ...
// };
//
// To fix that you must modify your structure:
//
// // C++03 and C++11 version
// struct T: private boost::noncopyable {
// ...
// private:
// T(const T &);
// ...
// };
//
// // C++11 version
// struct T {
// ...
// private:
// T(const T &) = delete;
// ...
// };
BOOST_STATIC_CONSTANT(bool, value = (
sizeof(test(
boost::declval<BOOST_DEDUCED_TYPENAME boost::add_reference<T const>::type>()
)) == sizeof(boost::type_traits::yes_type)
&&
!boost::is_rvalue_reference<T>::value
&& !boost::is_array<T>::value
));
};
template <class T>
struct is_copy_constructible_impl2<true, T> {
BOOST_STATIC_CONSTANT(bool, value = false);
};
template <class T>
struct is_copy_constructible_impl {
BOOST_STATIC_CONSTANT(bool, value = (
boost::detail::is_copy_constructible_impl2<
boost::is_noncopyable<T>::value,
T
>::value
));
};
} // namespace detail
template <class T> struct is_copy_constructible : public integral_constant<bool, ::boost::detail::is_copy_constructible_impl<T>::value>{};
template <> struct is_copy_constructible<void> : public false_type{};
#ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
template <> struct is_copy_constructible<void const> : public false_type{};
template <> struct is_copy_constructible<void volatile> : public false_type{};
template <> struct is_copy_constructible<void const volatile> : public false_type{};
#endif
} // namespace boost
#ifdef BOOST_MSVC
#pragma warning(pop)
#endif
#endif
#endif // BOOST_TT_IS_COPY_CONSTRUCTIBLE_HPP_INCLUDED