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Fallback for is_nothrow_swappable on pre-C++11

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This commit is contained in:
Daniel James
2017-11-28 22:12:01 +00:00
parent 1146f73070
commit 3e9608230c
3 changed files with 66 additions and 14 deletions
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7
doc/is_nothrow_swappable.qbk
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@ -1,4 +1,4 @@
[/
[/
Copyright 2017 Peter Dimov
Distributed under the Boost Software License, Version 1.0.
@ -16,7 +16,10 @@ __inherit If the expression `swap(declval<T&>(), declval<T&>())` (in a context
where `std::swap` is visible) is valid and non-throwing, inherits from
__true_type, otherwise from __false_type.
__compat This trait requires C++11.
__compat This trait requires C++11 for full support. Without C++11 it will
inherit from __true_type for scalar types (including integral, floating point,
enumeration, pointer and pointer-to-member types), and from __false_type for
anything else.
__header ` #include <boost/type_traits/is_nothrow_swappable.hpp>` or ` #include <boost/type_traits.hpp>`

14
include/boost/type_traits/is_nothrow_swappable.hpp
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@ -10,6 +10,20 @@
#include <boost/config.hpp>
#if defined(BOOST_NO_SFINAE_EXPR) || defined(BOOST_NO_CXX11_NOEXCEPT) || defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
#include <boost/type_traits/is_scalar.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/type_traits/integral_constant.hpp>
namespace boost
{
template <class T> struct is_nothrow_swappable : boost::integral_constant<bool,
boost::is_scalar<T>::value && !boost::is_const<T>::value> {};
template <class T, class U> struct is_nothrow_swappable_with : false_type {};
template <class T> struct is_nothrow_swappable_with<T, T> : is_nothrow_swappable<T> {};
}
#else
#include <boost/type_traits/declval.hpp>

59
test/is_nothrow_swappable_test.cpp
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@ -13,15 +13,6 @@
#include <boost/config.hpp>
#if defined(BOOST_NO_SFINAE_EXPR) || defined(BOOST_NO_CXX11_NOEXCEPT) || defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) \
|| (defined(__GLIBCXX__) && __GLIBCXX__ <= 20120301) // built-in clang++ -std=c++11 on Travis, w/ libstdc++ 4.6
int main()
{
}
#else
#include "test.hpp"
#include "check_integral_constant.hpp"
#include <utility>
@ -46,7 +37,13 @@ struct V
V& operator=( V const& ) { return *this; }
};
void swap( V&, V& ) noexcept {}
void swap( V&, V& ) BOOST_NOEXCEPT {}
struct U
{
};
void swap(U&, U&) {}
TT_TEST_BEGIN(is_nothrow_swappable)
@ -55,16 +52,49 @@ BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int const>::value, fals
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int volatile>::value, true);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int const volatile>::value, false);
#if defined(BOOST_NO_SFINAE_EXPR) || defined(BOOST_NO_CXX11_NOEXCEPT) || defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) \
|| (defined(__GLIBCXX__) && __GLIBCXX__ <= 20120301) // built-in clang++ -std=c++11 on Travis, w/ libstdc++ 4.6
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int const[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int volatile[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int const volatile[2]>::value, false);
#else
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int[2]>::value, true);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int const[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int volatile[2]>::value, true);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<int const volatile[2]>::value, false);
#endif
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<void>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<void const>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<void volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<void const volatile>::value, false);
#if defined(BOOST_NO_SFINAE_EXPR) || defined(BOOST_NO_CXX11_NOEXCEPT) || defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) \
|| (defined(__GLIBCXX__) && __GLIBCXX__ <= 20120301) // built-in clang++ -std=c++11 on Travis, w/ libstdc++ 4.6
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X const>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X const volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X const[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X volatile[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X const volatile[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<Z>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<Z const>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<Z volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<Z const volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U const>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U const volatile>::value, false);
#else
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X>::value, true);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X const>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<X volatile>::value, false);
@ -105,6 +135,11 @@ BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<V const[2]>::value, fal
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<V volatile[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<V const volatile[2]>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U const>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_swappable<U const volatile>::value, false);
BOOST_CHECK_INTEGRAL_CONSTANT((::tt::is_nothrow_swappable<std::pair<X, int> >::value), true);
BOOST_CHECK_INTEGRAL_CONSTANT((::tt::is_nothrow_swappable<std::pair<X, int> const>::value), false);
BOOST_CHECK_INTEGRAL_CONSTANT((::tt::is_nothrow_swappable<std::pair<X, int> volatile>::value), false);
@ -120,6 +155,6 @@ BOOST_CHECK_INTEGRAL_CONSTANT((::tt::is_nothrow_swappable<std::pair<V, int> cons
BOOST_CHECK_INTEGRAL_CONSTANT((::tt::is_nothrow_swappable<std::pair<V, int> volatile>::value), false);
BOOST_CHECK_INTEGRAL_CONSTANT((::tt::is_nothrow_swappable<std::pair<V, int> const volatile>::value), false);
TT_TEST_END
#endif
TT_TEST_END