b04445d4a8
C++20 isn't final quite yet, but all that remains is formalities, so let's go ahead and change all the references. I think for the next C++ standard we can just call it C++23 rather than C++2b, since the committee has been consistent about time-based releases rather than feature-based. gcc/c-family/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * c.opt (std=c++20): Make c++2a the alias. (std=gnu++20): Likewise. * c-common.h (cxx_dialect): Change cxx2a to cxx20. * c-opts.c: Adjust. * c-cppbuiltin.c: Adjust. * c-ubsan.c: Adjust. * c-warn.c: Adjust. gcc/cp/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * call.c, class.c, constexpr.c, constraint.cc, decl.c, init.c, lambda.c, lex.c, method.c, name-lookup.c, parser.c, pt.c, tree.c, typeck2.c: Change cxx2a to cxx20. libcpp/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * include/cpplib.h (enum c_lang): Change CXX2A to CXX20. * init.c, lex.c: Adjust.
80 lines
1.8 KiB
C
80 lines
1.8 KiB
C
// P0784R7
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// { dg-do compile { target c++20 } }
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namespace std
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{
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typedef __SIZE_TYPE__ size_t;
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template <typename T>
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struct allocator
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{
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constexpr allocator () noexcept {}
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constexpr T *allocate (size_t n)
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{ return static_cast<T *> (::operator new (n * sizeof(T))); }
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constexpr void
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deallocate (T *p, size_t n)
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{ ::operator delete (p); }
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};
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template <typename T, typename U = T &&>
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U __declval (int);
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template <typename T>
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T __declval (long);
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template <typename T>
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auto declval () noexcept -> decltype (__declval<T> (0));
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template <typename T>
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struct remove_reference
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{ typedef T type; };
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template <typename T>
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struct remove_reference<T &>
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{ typedef T type; };
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template <typename T>
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struct remove_reference<T &&>
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{ typedef T type; };
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template <typename T>
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constexpr T &&
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forward (typename std::remove_reference<T>::type &t) noexcept
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{ return static_cast<T&&> (t); }
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template<typename T>
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constexpr T &&
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forward (typename std::remove_reference<T>::type &&t) noexcept
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{ return static_cast<T&&> (t); }
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template <typename T, typename... A>
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constexpr auto
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construct_at (T *l, A &&... a)
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noexcept (noexcept (::new ((void *) 0) T (std::declval<A> ()...)))
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-> decltype (::new ((void *) 0) T (std::declval<A> ()...))
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{ return ::new ((void *) l) T (std::forward<A> (a)...); }
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template <typename T>
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constexpr inline void
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destroy_at (T *l)
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{ l->~T (); }
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}
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inline void *operator new (std::size_t, void *p) noexcept
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{ return p; }
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constexpr bool
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foo ()
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{
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std::allocator<int> a;
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auto p = a.allocate (2);
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std::construct_at (p, 1);
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std::construct_at (p + 1, 2);
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if (p[0] != 1 || p[1] != 2)
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throw 1;
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std::destroy_at (p);
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std::destroy_at (p + 1);
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a.deallocate (p, 2);
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return true;
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}
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static_assert (foo ());
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