- tmp/tmpl58frcar/{from.md → to.md} +466 -386
tmp/tmpl58frcar/{from.md → to.md}
RENAMED
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## Memory <a id="memory">[[memory]]</a>
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### In general <a id="memory.general">[[memory.general]]</a>
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This subclause describes the contents of the header `<memory>` (
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[[memory.syn]]) and some of the contents of the
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### Header `<memory>` synopsis <a id="memory.syn">[[memory.syn]]</a>
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The header `<memory>` defines several types and function templates that
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describe properties of pointers and pointer-like types, manage memory
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for containers and other template types,
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in uninitialized memory buffers ([[pointer.traits]]–
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[[specialized.algorithms]]). The header also defines the templates
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`unique_ptr`, `shared_ptr`, `weak_ptr`, and various function templates
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that operate on objects of these types ([[smartptr]]).
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``` cpp
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void declare_no_pointers(char* p, size_t n);
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void undeclare_no_pointers(char* p, size_t n);
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pointer_safety get_pointer_safety() noexcept;
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// [ptr.align], pointer alignment function
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void* align(
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void*& ptr, std::size_t& space);
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// [allocator.tag], allocator argument tag
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struct allocator_arg_t { };
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constexpr allocator_arg_t allocator_arg{};
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// [allocator.uses], uses_allocator
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template <class T, class Alloc> struct uses_allocator;
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// [allocator.traits], allocator traits
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template <class Alloc> struct allocator_traits;
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// [default.allocator], the default allocator
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template <class T> class allocator;
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template <> class allocator<void>;
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template <class T, class U>
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bool operator==(const allocator<T>&, const allocator<U>&) noexcept;
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template <class T, class U>
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bool operator!=(const allocator<T>&, const allocator<U>&) noexcept;
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// [
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template <class
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template <class
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template <class InputIterator, class ForwardIterator>
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ForwardIterator uninitialized_copy(InputIterator first, InputIterator last,
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ForwardIterator result);
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template <class InputIterator, class Size, class ForwardIterator>
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ForwardIterator uninitialized_copy_n(InputIterator first, Size n,
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ForwardIterator result);
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template <class ForwardIterator, class T>
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void uninitialized_fill(ForwardIterator first, ForwardIterator last,
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const T& x);
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template <class ForwardIterator, class Size, class T>
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ForwardIterator uninitialized_fill_n(ForwardIterator first, Size n, const T& x);
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// [unique.ptr] class template unique_ptr
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template <class T> struct default_delete;
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template <class T> struct default_delete<T[]>;
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template <class T, class D = default_delete<T>> class unique_ptr;
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template <class T, class D> class unique_ptr<T[], D>;
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template <class T, class D>
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bool operator>=(const unique_ptr<T, D>& x, nullptr_t);
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template <class T, class D>
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bool operator>=(nullptr_t, const unique_ptr<T, D>& y);
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// [util.smartptr.
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class bad_weak_ptr;
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// [util.smartptr.shared], class template shared_ptr
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template<class T> class shared_ptr;
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// [util.smartptr.shared.create], shared_ptr creation
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template<class T, class... Args>
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template<class T, class A, class... Args>
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shared_ptr<T> allocate_shared(const A& a, Args&&... args);
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// [util.smartptr.shared.cmp], shared_ptr comparisons
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template<class T, class U>
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bool operator==(shared_ptr<T>
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template<class T, class U>
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bool operator!=(shared_ptr<T>
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template<class T, class U>
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bool operator<(shared_ptr<T>
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template<class T, class U>
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bool operator>(shared_ptr<T>
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template<class T, class U>
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bool operator<=(shared_ptr<T>
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template<class T, class U>
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bool operator>=(shared_ptr<T>
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template <class T>
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bool operator==(const shared_ptr<T>& x, nullptr_t) noexcept;
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template <class T>
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bool operator==(nullptr_t, const shared_ptr<T>& y) noexcept;
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template <class T>
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bool operator>=(const shared_ptr<T>& x, nullptr_t) noexcept;
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template <class T>
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bool operator>=(nullptr_t, const shared_ptr<T>& y) noexcept;
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// [util.smartptr.shared.spec], shared_ptr specialized algorithms
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template<class T>
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// [util.smartptr.shared.cast], shared_ptr casts
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template<class T, class U>
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shared_ptr<T> static_pointer_cast(shared_ptr<U>
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template<class T, class U>
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shared_ptr<T> dynamic_pointer_cast(shared_ptr<U>
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template<class T, class U>
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shared_ptr<T> const_pointer_cast(shared_ptr<U>
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// [util.smartptr.getdeleter], shared_ptr get_deleter
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template<class D, class T>
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// [util.smartptr.shared.io], shared_ptr I/O
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template<class E, class T, class Y>
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basic_ostream<E, T>& operator<< (basic_ostream<E, T>& os, shared_ptr<Y>
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// [util.smartptr.weak], class template weak_ptr
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template<class T> class weak_ptr;
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// [util.smartptr.weak.spec], weak_ptr specialized algorithms
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template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b) noexcept;
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// [util.smartptr.ownerless], class template owner_less
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template<class T>
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// [util.smartptr.enab], class template enable_shared_from_this
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template<class T> class enable_shared_from_this;
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// [util.smartptr.shared.atomic], shared_ptr atomic access
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template<class T>
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bool atomic_is_lock_free(const shared_ptr<T>* p);
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template<class T>
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shared_ptr<T> atomic_load(const shared_ptr<T>* p);
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void atomic_store_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
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template<class T>
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shared_ptr<T> atomic_exchange(shared_ptr<T>* p, shared_ptr<T> r);
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template<class T>
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shared_ptr<T> atomic_exchange_explicit(shared_ptr<T>* p, shared_ptr<T> r,
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memory_order mo);
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template<class T>
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bool atomic_compare_exchange_weak(
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shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w);
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template<class T>
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template<class T>
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bool atomic_compare_exchange_strong_explicit(
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shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w,
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memory_order success, memory_order failure);
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// [util.smartptr.hash] hash support
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template <class T> struct hash;
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template <class T, class D> struct hash<unique_ptr<T, D>>;
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template <class T> struct hash<shared_ptr<T>>;
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// [
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template <class
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}
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```
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### Pointer traits <a id="pointer.traits">[[pointer.traits]]</a>
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certain attributes of pointer-like types.
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``` cpp
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namespace std {
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template <class Ptr> struct pointer_traits {
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-
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template <class U> using rebind = see below;
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static pointer pointer_to(see below r);
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};
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template <class T> struct pointer_traits<T*> {
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-
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-
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-
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template <class U> using rebind = U*;
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static pointer pointer_to(see below r) noexcept;
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};
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```
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#### Pointer traits member types <a id="pointer.traits.types">[[pointer.traits.types]]</a>
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``` cpp
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```
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*Type:* `Ptr::element_type` if
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`SomePointer<T, Args>`, where
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otherwise, the specialization is
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``` cpp
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```
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*Type:* `Ptr::difference_type` if
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`
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``` cpp
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template <class U> using rebind = see below;
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```
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*Alias template:* `Ptr::rebind<U>` if
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`
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#### Pointer traits member functions <a id="pointer.traits.functions">[[pointer.traits.functions]]</a>
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``` cpp
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static pointer pointer_traits::pointer_to(see below r);
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static pointer pointer_traits<T*>::pointer_to(see below r) noexcept;
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```
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If `element_type` is
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unspecified; otherwise, it is `element_type&`.
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*Returns:* The first member function returns a pointer to `r` obtained
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by calling `Ptr::pointer_to(r)` through which indirection is valid; an
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instantiation of this function is ill-formed if `Ptr` does not have a
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matching `pointer_to` static member function. The second member function
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returns `
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### Pointer safety <a id="util.dynamic.safety">[[util.dynamic.safety]]</a>
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A complete object is *declared reachable* while the number of calls to
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`declare_reachable` with an argument referencing the object exceeds the
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pointer ([[basic.stc.dynamic.safety]]) or a null pointer value.
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*Effects:* If `p` is not null, the complete object referenced by `p` is
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subsequently declared reachable ([[basic.stc.dynamic.safety]]).
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*Throws:* May throw `
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-
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reachable.
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``` cpp
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template <class T> T* undeclare_reachable(T* p);
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```
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*Returns:* A safely derived copy of `p` which shall compare equal to
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`p`.
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*Throws:* Nothing.
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It is expected that calls to `declare_reachable(p)` will
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amount of memory in addition to that occupied by the
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until the matching call to `undeclare_reachable(p)` is
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running programs should arrange that calls are
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``` cpp
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void declare_no_pointers(char* p, size_t n);
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```
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*Requires:* No bytes in the specified range are currently registered
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with `declare_no_pointers()`. If the specified range is in an allocated
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object, then it must be entirely within a single allocated object. The
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object must be live until the corresponding `undeclare_no_pointers()`
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call.
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-
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-
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*Effects:* The `n` bytes starting at `p` no longer contain traceable
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pointer locations, independent of their type. Hence indirection through
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a pointer located there is undefined if the object it points to was
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created by global `operator new` and not previously declared reachable.
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-
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-
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*Throws:* Nothing.
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Under some conditions implementations may need to allocate
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However, the request can be ignored if memory allocation
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``` cpp
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void undeclare_no_pointers(char* p, size_t n);
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```
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``` cpp
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pointer_safety get_pointer_safety() noexcept;
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```
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*Returns:* `pointer_safety::strict` if the implementation has strict
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pointer safety ([[basic.stc.dynamic.safety]]). It is
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defined whether `get_pointer_safety` returns
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or `pointer_safety::preferred` if the
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safety.[^1]
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### Align <a id="ptr.align">[[ptr.align]]</a>
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``` cpp
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void* align(
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void*& ptr, std::size_t& space);
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```
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*Effects:* If it is possible to fit `size` bytes of storage aligned by
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`alignment` into the buffer pointed to by `ptr` with length `space`, the
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function updates `ptr` to
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storage and decreases `space` by the number of bytes used for alignment.
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Otherwise, the function does nothing.
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*Requires:*
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- `alignment` shall be a
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-
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-
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*Returns:* A null pointer if the requested aligned buffer would not fit
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into the available space, otherwise the adjusted value of `ptr`.
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The function updates its `ptr` and `space` arguments so that
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called repeatedly with possibly different `alignment` and
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arguments for the same buffer.
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### Allocator argument tag <a id="allocator.tag">[[allocator.tag]]</a>
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``` cpp
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namespace std {
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struct allocator_arg_t { };
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constexpr allocator_arg_t allocator_arg{};
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}
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```
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The `allocator_arg_t` struct is an empty structure type used as a unique
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type to disambiguate constructor and function overloading. Specifically,
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@@ -457,74 +518,77 @@ argument of a type that satisfies the `Allocator` requirements (
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``` cpp
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template <class T, class Alloc> struct uses_allocator;
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```
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-
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convertible from `Alloc`. Meets the
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requirements ([[meta.rqmts]]). The implementation
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definition that is derived from `true_type` if
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`T::allocator_type`
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-
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shall be derived from `false_type`. A program may specialize this
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template to derive from `true_type` for a user-defined type `T` that
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does not have a nested `allocator_type` but nonetheless can be
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constructed with an allocator where either:
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- the first argument of a constructor has type `allocator_arg_t` and the
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second argument has type `Alloc` or
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- the last argument of a constructor has type `Alloc`.
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####
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*Uses-allocator construction* with allocator `Alloc` refers to the
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construction of an object `obj` of type `T`, using constructor arguments
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`v1, v2, ..., vN` of types `V1, V2, ..., VN`, respectively, and an
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allocator `alloc` of type `Alloc`, according to the following rules:
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- if `
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`
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initialized as `obj(v1, v2, ..., vN)`;
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-
- otherwise, if `
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-
`
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`
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-
`obj(allocator_arg, alloc, v1,
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v2, ..., vN)`;
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-
- otherwise, if `
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`
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-
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- otherwise, the request for uses-allocator construction is ill-formed.
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-
An error will result if `
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but the specific constructor does not take an allocator. This
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definition prevents a silent failure to pass the allocator to an
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element.
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### Allocator traits <a id="allocator.traits">[[allocator.traits]]</a>
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The class template `allocator_traits` supplies a uniform interface to
|
| 504 |
all allocator types. An allocator cannot be a non-class type, however,
|
| 505 |
-
even if `allocator_traits` supplies the entire required interface.
|
| 506 |
-
|
|
|
|
|
|
|
| 507 |
|
| 508 |
``` cpp
|
| 509 |
namespace std {
|
| 510 |
template <class Alloc> struct allocator_traits {
|
| 511 |
-
|
| 512 |
|
| 513 |
-
|
| 514 |
|
| 515 |
-
|
| 516 |
-
|
| 517 |
-
|
| 518 |
-
|
| 519 |
|
| 520 |
-
|
| 521 |
-
|
| 522 |
|
| 523 |
-
|
| 524 |
-
|
| 525 |
-
|
|
|
|
| 526 |
|
| 527 |
template <class T> using rebind_alloc = see below;
|
| 528 |
template <class T> using rebind_traits = allocator_traits<rebind_alloc<T>>;
|
| 529 |
|
| 530 |
static pointer allocate(Alloc& a, size_type n);
|
|
@@ -546,80 +610,99 @@ namespace std {
|
|
| 546 |
```
|
| 547 |
|
| 548 |
#### Allocator traits member types <a id="allocator.traits.types">[[allocator.traits.types]]</a>
|
| 549 |
|
| 550 |
``` cpp
|
| 551 |
-
|
| 552 |
```
|
| 553 |
|
| 554 |
-
*Type:* `Alloc::pointer` if
|
| 555 |
-
`value_type*`.
|
| 556 |
|
| 557 |
``` cpp
|
| 558 |
-
|
| 559 |
```
|
| 560 |
|
| 561 |
-
*Type:* `Alloc::const_pointer` if
|
| 562 |
-
`
|
|
|
|
| 563 |
|
| 564 |
``` cpp
|
| 565 |
-
|
| 566 |
```
|
| 567 |
|
| 568 |
-
*Type:* `Alloc::void_pointer` if
|
| 569 |
-
`
|
|
|
|
| 570 |
|
| 571 |
``` cpp
|
| 572 |
-
|
| 573 |
```
|
| 574 |
|
| 575 |
-
*Type:* `Alloc::const_void_pointer` if
|
|
|
|
|
|
|
| 576 |
`pointer_traits<pointer>::rebind<const void>`.
|
| 577 |
|
| 578 |
``` cpp
|
| 579 |
-
|
| 580 |
```
|
| 581 |
|
| 582 |
-
*Type:* `Alloc::difference_type` if
|
| 583 |
-
`
|
|
|
|
| 584 |
|
| 585 |
``` cpp
|
| 586 |
-
|
| 587 |
```
|
| 588 |
|
| 589 |
-
*Type:* `Alloc::size_type` if
|
|
|
|
| 590 |
`make_unsigned_t<difference_type>`.
|
| 591 |
|
| 592 |
``` cpp
|
| 593 |
-
|
| 594 |
```
|
| 595 |
|
| 596 |
-
*Type:* `Alloc::propagate_on_container_copy_assignment` if
|
| 597 |
-
|
|
|
|
| 598 |
|
| 599 |
``` cpp
|
| 600 |
-
|
| 601 |
```
|
| 602 |
|
| 603 |
-
*Type:* `Alloc::propagate_on_container_move_assignment` if
|
| 604 |
-
|
|
|
|
| 605 |
|
| 606 |
``` cpp
|
| 607 |
-
|
| 608 |
```
|
| 609 |
|
| 610 |
-
*Type:* `Alloc::propagate_on_container_swap` if
|
| 611 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 612 |
|
| 613 |
``` cpp
|
| 614 |
template <class T> using rebind_alloc = see below;
|
| 615 |
```
|
| 616 |
|
| 617 |
-
*Alias template:* `Alloc::rebind<T>::other` if
|
| 618 |
-
|
| 619 |
-
|
| 620 |
-
|
|
|
|
|
|
|
| 621 |
|
| 622 |
#### Allocator traits static member functions <a id="allocator.traits.members">[[allocator.traits.members]]</a>
|
| 623 |
|
| 624 |
``` cpp
|
| 625 |
static pointer allocate(Alloc& a, size_type n);
|
|
@@ -636,90 +719,65 @@ otherwise, `a.allocate(n)`.
|
|
| 636 |
|
| 637 |
``` cpp
|
| 638 |
static void deallocate(Alloc& a, pointer p, size_type n);
|
| 639 |
```
|
| 640 |
|
| 641 |
-
*Effects:*
|
| 642 |
|
| 643 |
*Throws:* Nothing.
|
| 644 |
|
| 645 |
``` cpp
|
| 646 |
template <class T, class... Args>
|
| 647 |
static void construct(Alloc& a, T* p, Args&&... args);
|
| 648 |
```
|
| 649 |
|
| 650 |
-
*Effects:*
|
| 651 |
call is well-formed; otherwise, invokes
|
| 652 |
`::new (static_cast<void*>(p)) T(std::forward<Args>(args)...)`.
|
| 653 |
|
| 654 |
``` cpp
|
| 655 |
template <class T>
|
| 656 |
static void destroy(Alloc& a, T* p);
|
| 657 |
```
|
| 658 |
|
| 659 |
-
*Effects:*
|
| 660 |
invokes `p->~T()`.
|
| 661 |
|
| 662 |
``` cpp
|
| 663 |
static size_type max_size(const Alloc& a) noexcept;
|
| 664 |
```
|
| 665 |
|
| 666 |
*Returns:* `a.max_size()` if that expression is well-formed; otherwise,
|
| 667 |
-
`numeric_limits<size_type>::max()`.
|
| 668 |
|
| 669 |
``` cpp
|
| 670 |
static Alloc select_on_container_copy_construction(const Alloc& rhs);
|
| 671 |
```
|
| 672 |
|
| 673 |
*Returns:* `rhs.select_on_container_copy_construction()` if that
|
| 674 |
expression is well-formed; otherwise, `rhs`.
|
| 675 |
|
| 676 |
### The default allocator <a id="default.allocator">[[default.allocator]]</a>
|
| 677 |
|
|
|
|
|
|
|
|
|
|
| 678 |
``` cpp
|
| 679 |
namespace std {
|
| 680 |
-
template <class T> class allocator;
|
| 681 |
-
|
| 682 |
-
// specialize for void:
|
| 683 |
-
template <> class allocator<void> {
|
| 684 |
-
public:
|
| 685 |
-
typedef void* pointer;
|
| 686 |
-
typedef const void* const_pointer;
|
| 687 |
-
// reference-to-void members are impossible.
|
| 688 |
-
typedef void value_type;
|
| 689 |
-
template <class U> struct rebind { typedef allocator<U> other; };
|
| 690 |
-
};
|
| 691 |
-
|
| 692 |
template <class T> class allocator {
|
| 693 |
public:
|
| 694 |
-
|
| 695 |
-
|
| 696 |
-
|
| 697 |
-
typedef const T* const_pointer;
|
| 698 |
-
typedef T& reference;
|
| 699 |
-
typedef const T& const_reference;
|
| 700 |
-
typedef T value_type;
|
| 701 |
-
template <class U> struct rebind { typedef allocator<U> other; };
|
| 702 |
-
typedef true_type propagate_on_container_move_assignment;
|
| 703 |
|
| 704 |
allocator() noexcept;
|
| 705 |
allocator(const allocator&) noexcept;
|
| 706 |
template <class U> allocator(const allocator<U>&) noexcept;
|
| 707 |
~allocator();
|
| 708 |
|
| 709 |
-
|
| 710 |
-
|
| 711 |
-
|
| 712 |
-
pointer allocate(
|
| 713 |
-
size_type, allocator<void>::const_pointer hint = 0);
|
| 714 |
-
void deallocate(pointer p, size_type n);
|
| 715 |
-
size_type max_size() const noexcept;
|
| 716 |
-
|
| 717 |
-
template<class U, class... Args>
|
| 718 |
-
void construct(U* p, Args&&... args);
|
| 719 |
-
template <class U>
|
| 720 |
-
void destroy(U* p);
|
| 721 |
};
|
| 722 |
}
|
| 723 |
```
|
| 724 |
|
| 725 |
#### `allocator` members <a id="allocator.members">[[allocator.members]]</a>
|
|
@@ -730,300 +788,322 @@ concurrent calls to those member functions from different threads. Calls
|
|
| 730 |
to these functions that allocate or deallocate a particular unit of
|
| 731 |
storage shall occur in a single total order, and each such deallocation
|
| 732 |
call shall happen before the next allocation (if any) in this order.
|
| 733 |
|
| 734 |
``` cpp
|
| 735 |
-
|
| 736 |
```
|
| 737 |
|
| 738 |
-
*Returns:* The actual address of the object referenced by `x`, even in
|
| 739 |
-
the presence of an overloaded operator&.
|
| 740 |
-
|
| 741 |
-
``` cpp
|
| 742 |
-
const_pointer address(const_reference x) const noexcept;
|
| 743 |
-
```
|
| 744 |
-
|
| 745 |
-
*Returns:* The actual address of the object referenced by `x`, even in
|
| 746 |
-
the presence of an overloaded operator&.
|
| 747 |
-
|
| 748 |
-
``` cpp
|
| 749 |
-
pointer allocate(size_type n, allocator<void>::const_pointer hint = 0);
|
| 750 |
-
```
|
| 751 |
-
|
| 752 |
-
In a container member function, the address of an adjacent element is
|
| 753 |
-
often a good choice to pass for the `hint` argument.
|
| 754 |
-
|
| 755 |
*Returns:* A pointer to the initial element of an array of storage of
|
| 756 |
size `n` `* sizeof(T)`, aligned appropriately for objects of type `T`.
|
| 757 |
-
It is *implementation-defined* whether over-aligned types are
|
| 758 |
-
supported ([[basic.align]]).
|
| 759 |
|
| 760 |
-
the storage is obtained by calling
|
| 761 |
-
`::operator new
|
| 762 |
-
|
| 763 |
-
unspecified, but intended as an aid to locality if an implementation so
|
| 764 |
-
desires.
|
| 765 |
|
| 766 |
*Throws:* `bad_alloc` if the storage cannot be obtained.
|
| 767 |
|
| 768 |
``` cpp
|
| 769 |
-
void deallocate(
|
| 770 |
```
|
| 771 |
|
| 772 |
*Requires:* `p` shall be a pointer value obtained from `allocate()`. `n`
|
| 773 |
shall equal the value passed as the first argument to the invocation of
|
| 774 |
allocate which returned `p`.
|
| 775 |
|
| 776 |
*Effects:* Deallocates the storage referenced by `p` .
|
| 777 |
|
| 778 |
-
*Remarks:* Uses
|
| 779 |
-
`::operator delete(void*, std::size_t)` ([[new.delete]]), but it is
|
| 780 |
unspecified when this function is called.
|
| 781 |
|
| 782 |
-
``` cpp
|
| 783 |
-
size_type max_size() const noexcept;
|
| 784 |
-
```
|
| 785 |
-
|
| 786 |
-
*Returns:* The largest value *N* for which the call `allocate(N,0)`
|
| 787 |
-
might succeed.
|
| 788 |
-
|
| 789 |
-
``` cpp
|
| 790 |
-
template <class U, class... Args>
|
| 791 |
-
void construct(U* p, Args&&... args);
|
| 792 |
-
```
|
| 793 |
-
|
| 794 |
-
*Effects:* `::new((void *)p) U(std::forward<Args>(args)...)`
|
| 795 |
-
|
| 796 |
-
``` cpp
|
| 797 |
-
template <class U>
|
| 798 |
-
void destroy(U* p);
|
| 799 |
-
```
|
| 800 |
-
|
| 801 |
-
*Effects:* `p->~U()`
|
| 802 |
-
|
| 803 |
#### `allocator` globals <a id="allocator.globals">[[allocator.globals]]</a>
|
| 804 |
|
| 805 |
``` cpp
|
| 806 |
-
template <class
|
| 807 |
-
bool operator==(const allocator<
|
| 808 |
```
|
| 809 |
|
| 810 |
*Returns:* `true`.
|
| 811 |
|
| 812 |
``` cpp
|
| 813 |
-
template <class
|
| 814 |
-
bool operator!=(const allocator<
|
| 815 |
```
|
| 816 |
|
| 817 |
*Returns:* `false`.
|
| 818 |
|
| 819 |
-
### Raw storage iterator <a id="storage.iterator">[[storage.iterator]]</a>
|
| 820 |
-
|
| 821 |
-
`raw_storage_iterator` is provided to enable algorithms to store their
|
| 822 |
-
results into uninitialized memory. The template parameter
|
| 823 |
-
`OutputIterator` is required to have its `operator*` return an object
|
| 824 |
-
for which `operator&` is defined and returns a pointer to `T`, and is
|
| 825 |
-
also required to satisfy the requirements of an output iterator (
|
| 826 |
-
[[output.iterators]]).
|
| 827 |
-
|
| 828 |
-
``` cpp
|
| 829 |
-
namespace std {
|
| 830 |
-
template <class OutputIterator, class T>
|
| 831 |
-
class raw_storage_iterator
|
| 832 |
-
: public iterator<output_iterator_tag,void,void,void,void> {
|
| 833 |
-
public:
|
| 834 |
-
explicit raw_storage_iterator(OutputIterator x);
|
| 835 |
-
|
| 836 |
-
raw_storage_iterator& operator*();
|
| 837 |
-
raw_storage_iterator& operator=(const T& element);
|
| 838 |
-
raw_storage_iterator& operator++();
|
| 839 |
-
raw_storage_iterator operator++(int);
|
| 840 |
-
};
|
| 841 |
-
}
|
| 842 |
-
```
|
| 843 |
-
|
| 844 |
-
``` cpp
|
| 845 |
-
explicit raw_storage_iterator(OutputIterator x);
|
| 846 |
-
```
|
| 847 |
-
|
| 848 |
-
*Effects:* Initializes the iterator to point to the same value to which
|
| 849 |
-
`x` points.
|
| 850 |
-
|
| 851 |
-
``` cpp
|
| 852 |
-
raw_storage_iterator& operator*();
|
| 853 |
-
```
|
| 854 |
-
|
| 855 |
-
*Returns:* `*this`
|
| 856 |
-
|
| 857 |
-
``` cpp
|
| 858 |
-
raw_storage_iterator& operator=(const T& element);
|
| 859 |
-
```
|
| 860 |
-
|
| 861 |
-
*Effects:* Constructs a value from `element` at the location to which
|
| 862 |
-
the iterator points.
|
| 863 |
-
|
| 864 |
-
*Returns:* A reference to the iterator.
|
| 865 |
-
|
| 866 |
-
``` cpp
|
| 867 |
-
raw_storage_iterator& operator++();
|
| 868 |
-
```
|
| 869 |
-
|
| 870 |
-
*Effects:* Pre-increment: advances the iterator and returns a reference
|
| 871 |
-
to the updated iterator.
|
| 872 |
-
|
| 873 |
-
``` cpp
|
| 874 |
-
raw_storage_iterator operator++(int);
|
| 875 |
-
```
|
| 876 |
-
|
| 877 |
-
*Effects:* Post-increment: advances the iterator and returns the old
|
| 878 |
-
value of the iterator.
|
| 879 |
-
|
| 880 |
-
### Temporary buffers <a id="temporary.buffer">[[temporary.buffer]]</a>
|
| 881 |
-
|
| 882 |
-
``` cpp
|
| 883 |
-
template <class T>
|
| 884 |
-
pair<T*, ptrdiff_t> get_temporary_buffer(ptrdiff_t n) noexcept;
|
| 885 |
-
```
|
| 886 |
-
|
| 887 |
-
*Effects:* Obtains a pointer to storage sufficient to store up to `n`
|
| 888 |
-
adjacent `T` objects. It is *implementation-defined* whether
|
| 889 |
-
over-aligned types are supported ([[basic.align]]).
|
| 890 |
-
|
| 891 |
-
*Returns:* A `pair` containing the buffer’s address and capacity (in the
|
| 892 |
-
units of `sizeof(T)`), or a pair of 0 values if no storage can be
|
| 893 |
-
obtained or if `n <= 0`.
|
| 894 |
-
|
| 895 |
-
``` cpp
|
| 896 |
-
template <class T> void return_temporary_buffer(T* p);
|
| 897 |
-
```
|
| 898 |
-
|
| 899 |
-
*Effects:* Deallocates the buffer to which `p` points.
|
| 900 |
-
|
| 901 |
-
*Requires:* The buffer shall have been previously allocated by
|
| 902 |
-
`get_temporary_buffer`.
|
| 903 |
-
|
| 904 |
### Specialized algorithms <a id="specialized.algorithms">[[specialized.algorithms]]</a>
|
| 905 |
|
| 906 |
-
|
| 907 |
-
|
| 908 |
-
|
| 909 |
-
|
| 910 |
-
|
| 911 |
-
[[input.iterators]]).
|
| 912 |
-
|
| 913 |
-
|
|
|
|
| 914 |
property that no exceptions are thrown from increment, assignment,
|
| 915 |
-
comparison, or indirection through valid iterators.
|
| 916 |
-
|
|
|
|
|
|
|
| 917 |
|
| 918 |
#### `addressof` <a id="specialized.addressof">[[specialized.addressof]]</a>
|
| 919 |
|
| 920 |
``` cpp
|
| 921 |
-
template <class T> T* addressof(T& r) noexcept;
|
| 922 |
```
|
| 923 |
|
| 924 |
*Returns:* The actual address of the object or function referenced by
|
| 925 |
`r`, even in the presence of an overloaded `operator&`.
|
| 926 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
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|
|
|
|
|
|
|
|
|
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|
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|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 927 |
#### `uninitialized_copy` <a id="uninitialized.copy">[[uninitialized.copy]]</a>
|
| 928 |
|
| 929 |
``` cpp
|
| 930 |
template <class InputIterator, class ForwardIterator>
|
| 931 |
ForwardIterator uninitialized_copy(InputIterator first, InputIterator last,
|
| 932 |
ForwardIterator result);
|
| 933 |
```
|
| 934 |
|
| 935 |
-
*Effects:*
|
| 936 |
|
| 937 |
``` cpp
|
| 938 |
-
for (; first != last; ++result, ++first)
|
| 939 |
-
::new (static_cast<void*>(
|
| 940 |
typename iterator_traits<ForwardIterator>::value_type(*first);
|
| 941 |
```
|
| 942 |
|
| 943 |
-
*Returns:* `result`
|
| 944 |
|
| 945 |
``` cpp
|
| 946 |
template <class InputIterator, class Size, class ForwardIterator>
|
| 947 |
ForwardIterator uninitialized_copy_n(InputIterator first, Size n,
|
| 948 |
ForwardIterator result);
|
| 949 |
```
|
| 950 |
|
| 951 |
-
*Effects:*
|
| 952 |
|
| 953 |
``` cpp
|
| 954 |
-
for ( ; n > 0; ++result, ++first, --n) {
|
| 955 |
-
::new (static_cast<void*>(
|
| 956 |
typename iterator_traits<ForwardIterator>::value_type(*first);
|
| 957 |
}
|
| 958 |
```
|
| 959 |
|
| 960 |
-
*Returns:* `result`
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
| 961 |
|
| 962 |
#### `uninitialized_fill` <a id="uninitialized.fill">[[uninitialized.fill]]</a>
|
| 963 |
|
| 964 |
``` cpp
|
| 965 |
template <class ForwardIterator, class T>
|
| 966 |
void uninitialized_fill(ForwardIterator first, ForwardIterator last,
|
| 967 |
const T& x);
|
| 968 |
```
|
| 969 |
|
| 970 |
-
*Effects:*
|
| 971 |
|
| 972 |
``` cpp
|
| 973 |
for (; first != last; ++first)
|
| 974 |
-
::new (static_cast<void*>(
|
| 975 |
typename iterator_traits<ForwardIterator>::value_type(x);
|
| 976 |
```
|
| 977 |
|
| 978 |
-
#### `uninitialized_fill_n` <a id="uninitialized.fill.n">[[uninitialized.fill.n]]</a>
|
| 979 |
-
|
| 980 |
``` cpp
|
| 981 |
template <class ForwardIterator, class Size, class T>
|
| 982 |
ForwardIterator uninitialized_fill_n(ForwardIterator first, Size n, const T& x);
|
| 983 |
```
|
| 984 |
|
| 985 |
-
*Effects:*
|
| 986 |
|
| 987 |
``` cpp
|
| 988 |
for (; n--; ++first)
|
| 989 |
-
::new (static_cast<void*>(
|
| 990 |
typename iterator_traits<ForwardIterator>::value_type(x);
|
| 991 |
return first;
|
| 992 |
```
|
| 993 |
|
| 994 |
-
###
|
| 995 |
|
| 996 |
-
|
|
|
|
|
|
|
|
|
|
| 997 |
|
| 998 |
-
|
| 999 |
-
with the following changes:
|
| 1000 |
|
| 1001 |
-
|
| 1002 |
-
|
|
|
|
| 1003 |
|
| 1004 |
-
|
| 1005 |
-
|
|
|
|
|
|
|
| 1006 |
|
| 1007 |
-
|
| 1008 |
|
| 1009 |
-
|
| 1010 |
-
|
| 1011 |
-
|
| 1012 |
-
|
| 1013 |
-
|
| 1014 |
-
|
| 1015 |
-
|
| 1016 |
-
|
| 1017 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
|
|
|
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|
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|
|
|
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|
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|
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|
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|
|
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|
|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1018 |
`declare_reachable()` implementation. The above functions should never
|
| 1019 |
intentionally be used as a replacement for `declare_reachable()`, and
|
| 1020 |
newly written code is strongly encouraged to treat memory allocated with
|
| 1021 |
-
these functions as though it were allocated with
|
|
|
|
| 1022 |
|
| 1023 |
-
|
|
|
|
|
|
|
| 1024 |
|
| 1025 |
-
|
| 1026 |
-
|
| 1027 |
|
| 1028 |
-
|
|
|
|
|
|
|
|
|
|
| 1029 |
|
|
|
|
| 1 |
## Memory <a id="memory">[[memory]]</a>
|
| 2 |
|
| 3 |
### In general <a id="memory.general">[[memory.general]]</a>
|
| 4 |
|
| 5 |
This subclause describes the contents of the header `<memory>` (
|
| 6 |
+
[[memory.syn]]) and some of the contents of the header `<cstdlib>` (
|
| 7 |
+
[[cstdlib.syn]]).
|
| 8 |
|
| 9 |
### Header `<memory>` synopsis <a id="memory.syn">[[memory.syn]]</a>
|
| 10 |
|
| 11 |
The header `<memory>` defines several types and function templates that
|
| 12 |
describe properties of pointers and pointer-like types, manage memory
|
| 13 |
+
for containers and other template types, destroy objects, and construct
|
| 14 |
+
multiple objects in uninitialized memory buffers ([[pointer.traits]]–
|
| 15 |
[[specialized.algorithms]]). The header also defines the templates
|
| 16 |
`unique_ptr`, `shared_ptr`, `weak_ptr`, and various function templates
|
| 17 |
that operate on objects of these types ([[smartptr]]).
|
| 18 |
|
| 19 |
``` cpp
|
|
|
|
| 29 |
void declare_no_pointers(char* p, size_t n);
|
| 30 |
void undeclare_no_pointers(char* p, size_t n);
|
| 31 |
pointer_safety get_pointer_safety() noexcept;
|
| 32 |
|
| 33 |
// [ptr.align], pointer alignment function
|
| 34 |
+
void* align(size_t alignment, size_t size, void*& ptr, size_t& space);
|
|
|
|
| 35 |
|
| 36 |
// [allocator.tag], allocator argument tag
|
| 37 |
+
struct allocator_arg_t { explicit allocator_arg_t() = default; };
|
| 38 |
+
inline constexpr allocator_arg_t allocator_arg{};
|
| 39 |
|
| 40 |
// [allocator.uses], uses_allocator
|
| 41 |
template <class T, class Alloc> struct uses_allocator;
|
| 42 |
|
| 43 |
// [allocator.traits], allocator traits
|
| 44 |
template <class Alloc> struct allocator_traits;
|
| 45 |
|
| 46 |
+
// [default.allocator], the default allocator
|
| 47 |
template <class T> class allocator;
|
|
|
|
| 48 |
template <class T, class U>
|
| 49 |
bool operator==(const allocator<T>&, const allocator<U>&) noexcept;
|
| 50 |
template <class T, class U>
|
| 51 |
bool operator!=(const allocator<T>&, const allocator<U>&) noexcept;
|
| 52 |
|
| 53 |
+
// [specialized.algorithms], specialized algorithms
|
| 54 |
+
template <class T> constexpr T* addressof(T& r) noexcept;
|
| 55 |
+
template <class T> const T* addressof(const T&&) = delete;
|
| 56 |
+
template <class ForwardIterator>
|
| 57 |
+
void uninitialized_default_construct(ForwardIterator first, ForwardIterator last);
|
| 58 |
+
template <class ExecutionPolicy, class ForwardIterator>
|
| 59 |
+
void uninitialized_default_construct(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 60 |
+
ForwardIterator first, ForwardIterator last);
|
| 61 |
+
template <class ForwardIterator, class Size>
|
| 62 |
+
ForwardIterator uninitialized_default_construct_n(ForwardIterator first, Size n);
|
| 63 |
+
template <class ExecutionPolicy, class ForwardIterator, class Size>
|
| 64 |
+
ForwardIterator uninitialized_default_construct_n(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 65 |
+
ForwardIterator first, Size n);
|
| 66 |
+
template <class ForwardIterator>
|
| 67 |
+
void uninitialized_value_construct(ForwardIterator first, ForwardIterator last);
|
| 68 |
+
template <class ExecutionPolicy, class ForwardIterator>
|
| 69 |
+
void uninitialized_value_construct(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 70 |
+
ForwardIterator first, ForwardIterator last);
|
| 71 |
+
template <class ForwardIterator, class Size>
|
| 72 |
+
ForwardIterator uninitialized_value_construct_n(ForwardIterator first, Size n);
|
| 73 |
+
template <class ExecutionPolicy, class ForwardIterator, class Size>
|
| 74 |
+
ForwardIterator uninitialized_value_construct_n(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 75 |
+
ForwardIterator first, Size n);
|
| 76 |
template <class InputIterator, class ForwardIterator>
|
| 77 |
ForwardIterator uninitialized_copy(InputIterator first, InputIterator last,
|
| 78 |
ForwardIterator result);
|
| 79 |
+
template <class ExecutionPolicy, class InputIterator, class ForwardIterator>
|
| 80 |
+
ForwardIterator uninitialized_copy(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 81 |
+
InputIterator first, InputIterator last,
|
| 82 |
+
ForwardIterator result);
|
| 83 |
template <class InputIterator, class Size, class ForwardIterator>
|
| 84 |
ForwardIterator uninitialized_copy_n(InputIterator first, Size n,
|
| 85 |
ForwardIterator result);
|
| 86 |
+
template <class ExecutionPolicy, class InputIterator, class Size, class ForwardIterator>
|
| 87 |
+
ForwardIterator uninitialized_copy_n(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 88 |
+
InputIterator first, Size n,
|
| 89 |
+
ForwardIterator result);
|
| 90 |
+
template <class InputIterator, class ForwardIterator>
|
| 91 |
+
ForwardIterator uninitialized_move(InputIterator first, InputIterator last,
|
| 92 |
+
ForwardIterator result);
|
| 93 |
+
template <class ExecutionPolicy, class InputIterator, class ForwardIterator>
|
| 94 |
+
ForwardIterator uninitialized_move(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 95 |
+
InputIterator first, InputIterator last,
|
| 96 |
+
ForwardIterator result);
|
| 97 |
+
template <class InputIterator, class Size, class ForwardIterator>
|
| 98 |
+
pair<InputIterator, ForwardIterator>
|
| 99 |
+
uninitialized_move_n(InputIterator first, Size n, ForwardIterator result);
|
| 100 |
+
template <class ExecutionPolicy, class InputIterator, class Size, class ForwardIterator>
|
| 101 |
+
pair<InputIterator, ForwardIterator>
|
| 102 |
+
uninitialized_move_n(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 103 |
+
InputIterator first, Size n, ForwardIterator result);
|
| 104 |
template <class ForwardIterator, class T>
|
| 105 |
void uninitialized_fill(ForwardIterator first, ForwardIterator last,
|
| 106 |
const T& x);
|
| 107 |
+
template <class ExecutionPolicy, class ForwardIterator, class T>
|
| 108 |
+
void uninitialized_fill(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 109 |
+
ForwardIterator first, ForwardIterator last,
|
| 110 |
+
const T& x);
|
| 111 |
template <class ForwardIterator, class Size, class T>
|
| 112 |
ForwardIterator uninitialized_fill_n(ForwardIterator first, Size n, const T& x);
|
| 113 |
+
template <class ExecutionPolicy, class ForwardIterator, class Size, class T>
|
| 114 |
+
ForwardIterator uninitialized_fill_n(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 115 |
+
ForwardIterator first, Size n, const T& x);
|
| 116 |
+
template <class T>
|
| 117 |
+
void destroy_at(T* location);
|
| 118 |
+
template <class ForwardIterator>
|
| 119 |
+
void destroy(ForwardIterator first, ForwardIterator last);
|
| 120 |
+
template <class ExecutionPolicy, class ForwardIterator>
|
| 121 |
+
void destroy(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 122 |
+
ForwardIterator first, ForwardIterator last);
|
| 123 |
+
template <class ForwardIterator, class Size>
|
| 124 |
+
ForwardIterator destroy_n(ForwardIterator first, Size n);
|
| 125 |
+
template <class ExecutionPolicy, class ForwardIterator, class Size>
|
| 126 |
+
ForwardIterator destroy_n(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 127 |
+
ForwardIterator first, Size n);
|
| 128 |
|
| 129 |
+
// [unique.ptr], class template unique_ptr
|
| 130 |
template <class T> struct default_delete;
|
| 131 |
template <class T> struct default_delete<T[]>;
|
| 132 |
template <class T, class D = default_delete<T>> class unique_ptr;
|
| 133 |
template <class T, class D> class unique_ptr<T[], D>;
|
| 134 |
|
|
|
|
| 174 |
template <class T, class D>
|
| 175 |
bool operator>=(const unique_ptr<T, D>& x, nullptr_t);
|
| 176 |
template <class T, class D>
|
| 177 |
bool operator>=(nullptr_t, const unique_ptr<T, D>& y);
|
| 178 |
|
| 179 |
+
// [util.smartptr.weak.bad], class bad_weak_ptr
|
| 180 |
class bad_weak_ptr;
|
| 181 |
|
| 182 |
+
// [util.smartptr.shared], class template shared_ptr
|
| 183 |
template<class T> class shared_ptr;
|
| 184 |
|
| 185 |
// [util.smartptr.shared.create], shared_ptr creation
|
| 186 |
+
template<class T, class... Args>
|
| 187 |
+
shared_ptr<T> make_shared(Args&&... args);
|
| 188 |
template<class T, class A, class... Args>
|
| 189 |
shared_ptr<T> allocate_shared(const A& a, Args&&... args);
|
| 190 |
|
| 191 |
+
// [util.smartptr.shared.cmp], shared_ptr comparisons
|
| 192 |
template<class T, class U>
|
| 193 |
+
bool operator==(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
|
| 194 |
template<class T, class U>
|
| 195 |
+
bool operator!=(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
|
| 196 |
template<class T, class U>
|
| 197 |
+
bool operator<(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
|
| 198 |
template<class T, class U>
|
| 199 |
+
bool operator>(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
|
| 200 |
template<class T, class U>
|
| 201 |
+
bool operator<=(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
|
| 202 |
template<class T, class U>
|
| 203 |
+
bool operator>=(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
|
| 204 |
|
| 205 |
template <class T>
|
| 206 |
bool operator==(const shared_ptr<T>& x, nullptr_t) noexcept;
|
| 207 |
template <class T>
|
| 208 |
bool operator==(nullptr_t, const shared_ptr<T>& y) noexcept;
|
|
|
|
| 225 |
template <class T>
|
| 226 |
bool operator>=(const shared_ptr<T>& x, nullptr_t) noexcept;
|
| 227 |
template <class T>
|
| 228 |
bool operator>=(nullptr_t, const shared_ptr<T>& y) noexcept;
|
| 229 |
|
| 230 |
+
// [util.smartptr.shared.spec], shared_ptr specialized algorithms
|
| 231 |
+
template<class T>
|
| 232 |
+
void swap(shared_ptr<T>& a, shared_ptr<T>& b) noexcept;
|
| 233 |
|
| 234 |
+
// [util.smartptr.shared.cast], shared_ptr casts
|
| 235 |
template<class T, class U>
|
| 236 |
+
shared_ptr<T> static_pointer_cast(const shared_ptr<U>& r) noexcept;
|
| 237 |
template<class T, class U>
|
| 238 |
+
shared_ptr<T> dynamic_pointer_cast(const shared_ptr<U>& r) noexcept;
|
| 239 |
template<class T, class U>
|
| 240 |
+
shared_ptr<T> const_pointer_cast(const shared_ptr<U>& r) noexcept;
|
| 241 |
|
| 242 |
+
// [util.smartptr.getdeleter], shared_ptr get_deleter
|
| 243 |
+
template<class D, class T>
|
| 244 |
+
D* get_deleter(const shared_ptr<T>& p) noexcept;
|
| 245 |
|
| 246 |
+
// [util.smartptr.shared.io], shared_ptr I/O
|
| 247 |
template<class E, class T, class Y>
|
| 248 |
+
basic_ostream<E, T>& operator<< (basic_ostream<E, T>& os, const shared_ptr<Y>& p);
|
| 249 |
|
| 250 |
+
// [util.smartptr.weak], class template weak_ptr
|
| 251 |
template<class T> class weak_ptr;
|
| 252 |
|
| 253 |
+
// [util.smartptr.weak.spec], weak_ptr specialized algorithms
|
| 254 |
template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b) noexcept;
|
| 255 |
|
| 256 |
+
// [util.smartptr.ownerless], class template owner_less
|
| 257 |
+
template<class T = void> struct owner_less;
|
| 258 |
|
| 259 |
+
// [util.smartptr.enab], class template enable_shared_from_this
|
| 260 |
template<class T> class enable_shared_from_this;
|
| 261 |
|
| 262 |
+
// [util.smartptr.shared.atomic], shared_ptr atomic access
|
| 263 |
template<class T>
|
| 264 |
bool atomic_is_lock_free(const shared_ptr<T>* p);
|
| 265 |
|
| 266 |
template<class T>
|
| 267 |
shared_ptr<T> atomic_load(const shared_ptr<T>* p);
|
|
|
|
| 274 |
void atomic_store_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
|
| 275 |
|
| 276 |
template<class T>
|
| 277 |
shared_ptr<T> atomic_exchange(shared_ptr<T>* p, shared_ptr<T> r);
|
| 278 |
template<class T>
|
| 279 |
+
shared_ptr<T> atomic_exchange_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
|
|
|
|
| 280 |
|
| 281 |
template<class T>
|
| 282 |
bool atomic_compare_exchange_weak(
|
| 283 |
shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w);
|
| 284 |
template<class T>
|
|
|
|
| 291 |
template<class T>
|
| 292 |
bool atomic_compare_exchange_strong_explicit(
|
| 293 |
shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w,
|
| 294 |
memory_order success, memory_order failure);
|
| 295 |
|
| 296 |
+
// [util.smartptr.hash], hash support
|
| 297 |
template <class T> struct hash;
|
| 298 |
template <class T, class D> struct hash<unique_ptr<T, D>>;
|
| 299 |
template <class T> struct hash<shared_ptr<T>>;
|
| 300 |
|
| 301 |
+
// [allocator.uses.trait], uses_allocator
|
| 302 |
+
template <class T, class Alloc>
|
| 303 |
+
inline constexpr bool uses_allocator_v = uses_allocator<T, Alloc>::value;
|
| 304 |
}
|
| 305 |
```
|
| 306 |
|
| 307 |
### Pointer traits <a id="pointer.traits">[[pointer.traits]]</a>
|
| 308 |
|
|
|
|
| 310 |
certain attributes of pointer-like types.
|
| 311 |
|
| 312 |
``` cpp
|
| 313 |
namespace std {
|
| 314 |
template <class Ptr> struct pointer_traits {
|
| 315 |
+
using pointer = Ptr;
|
| 316 |
+
using element_type = see below;
|
| 317 |
+
using difference_type = see below;
|
| 318 |
|
| 319 |
template <class U> using rebind = see below;
|
| 320 |
|
| 321 |
static pointer pointer_to(see below r);
|
| 322 |
};
|
| 323 |
|
| 324 |
template <class T> struct pointer_traits<T*> {
|
| 325 |
+
using pointer = T*;
|
| 326 |
+
using element_type = T;
|
| 327 |
+
using difference_type = ptrdiff_t;
|
| 328 |
|
| 329 |
template <class U> using rebind = U*;
|
| 330 |
|
| 331 |
static pointer pointer_to(see below r) noexcept;
|
| 332 |
};
|
|
|
|
| 334 |
```
|
| 335 |
|
| 336 |
#### Pointer traits member types <a id="pointer.traits.types">[[pointer.traits.types]]</a>
|
| 337 |
|
| 338 |
``` cpp
|
| 339 |
+
using element_type = see below;
|
| 340 |
```
|
| 341 |
|
| 342 |
+
*Type:* `Ptr::element_type` if the *qualified-id* `Ptr::element_type` is
|
| 343 |
+
valid and denotes a type ([[temp.deduct]]); otherwise, `T` if `Ptr` is
|
| 344 |
+
a class template instantiation of the form `SomePointer<T, Args>`, where
|
| 345 |
+
`Args` is zero or more type arguments; otherwise, the specialization is
|
| 346 |
+
ill-formed.
|
| 347 |
|
| 348 |
``` cpp
|
| 349 |
+
using difference_type = see below;
|
| 350 |
```
|
| 351 |
|
| 352 |
+
*Type:* `Ptr::difference_type` if the *qualified-id*
|
| 353 |
+
`Ptr::difference_type` is valid and denotes a type ([[temp.deduct]]);
|
| 354 |
+
otherwise, `ptrdiff_t`.
|
| 355 |
|
| 356 |
``` cpp
|
| 357 |
template <class U> using rebind = see below;
|
| 358 |
```
|
| 359 |
|
| 360 |
+
*Alias template:* `Ptr::rebind<U>` if the *qualified-id*
|
| 361 |
+
`Ptr::rebind<U>` is valid and denotes a type ([[temp.deduct]]);
|
| 362 |
+
otherwise, `SomePointer<U, Args>` if `Ptr` is a class template
|
| 363 |
+
instantiation of the form `SomePointer<T, Args>`, where `Args` is zero
|
| 364 |
+
or more type arguments; otherwise, the instantiation of `rebind` is
|
| 365 |
+
ill-formed.
|
| 366 |
|
| 367 |
#### Pointer traits member functions <a id="pointer.traits.functions">[[pointer.traits.functions]]</a>
|
| 368 |
|
| 369 |
``` cpp
|
| 370 |
static pointer pointer_traits::pointer_to(see below r);
|
| 371 |
static pointer pointer_traits<T*>::pointer_to(see below r) noexcept;
|
| 372 |
```
|
| 373 |
|
| 374 |
+
*Remarks:* If `element_type` is cv `void`, the type of `r` is
|
| 375 |
unspecified; otherwise, it is `element_type&`.
|
| 376 |
|
| 377 |
*Returns:* The first member function returns a pointer to `r` obtained
|
| 378 |
by calling `Ptr::pointer_to(r)` through which indirection is valid; an
|
| 379 |
instantiation of this function is ill-formed if `Ptr` does not have a
|
| 380 |
matching `pointer_to` static member function. The second member function
|
| 381 |
+
returns `addressof(r)`.
|
| 382 |
|
| 383 |
### Pointer safety <a id="util.dynamic.safety">[[util.dynamic.safety]]</a>
|
| 384 |
|
| 385 |
A complete object is *declared reachable* while the number of calls to
|
| 386 |
`declare_reachable` with an argument referencing the object exceeds the
|
|
|
|
| 395 |
pointer ([[basic.stc.dynamic.safety]]) or a null pointer value.
|
| 396 |
|
| 397 |
*Effects:* If `p` is not null, the complete object referenced by `p` is
|
| 398 |
subsequently declared reachable ([[basic.stc.dynamic.safety]]).
|
| 399 |
|
| 400 |
+
*Throws:* May throw `bad_alloc` if the system cannot allocate additional
|
| 401 |
+
memory that may be required to track objects declared reachable.
|
|
|
|
| 402 |
|
| 403 |
``` cpp
|
| 404 |
template <class T> T* undeclare_reachable(T* p);
|
| 405 |
```
|
| 406 |
|
|
|
|
| 412 |
*Returns:* A safely derived copy of `p` which shall compare equal to
|
| 413 |
`p`.
|
| 414 |
|
| 415 |
*Throws:* Nothing.
|
| 416 |
|
| 417 |
+
[*Note 1*: It is expected that calls to `declare_reachable(p)` will
|
| 418 |
+
consume a small amount of memory in addition to that occupied by the
|
| 419 |
+
referenced object until the matching call to `undeclare_reachable(p)` is
|
| 420 |
+
encountered. Long running programs should arrange that calls are
|
| 421 |
+
matched. — *end note*]
|
| 422 |
|
| 423 |
``` cpp
|
| 424 |
void declare_no_pointers(char* p, size_t n);
|
| 425 |
```
|
| 426 |
|
| 427 |
*Requires:* No bytes in the specified range are currently registered
|
| 428 |
with `declare_no_pointers()`. If the specified range is in an allocated
|
| 429 |
object, then it must be entirely within a single allocated object. The
|
| 430 |
object must be live until the corresponding `undeclare_no_pointers()`
|
| 431 |
+
call.
|
| 432 |
+
|
| 433 |
+
[*Note 2*: In a garbage-collecting implementation, the fact that a
|
| 434 |
+
region in an object is registered with `declare_no_pointers()` should
|
| 435 |
+
not prevent the object from being collected. — *end note*]
|
| 436 |
|
| 437 |
*Effects:* The `n` bytes starting at `p` no longer contain traceable
|
| 438 |
pointer locations, independent of their type. Hence indirection through
|
| 439 |
a pointer located there is undefined if the object it points to was
|
| 440 |
created by global `operator new` and not previously declared reachable.
|
| 441 |
+
|
| 442 |
+
[*Note 3*: This may be used to inform a garbage collector or leak
|
| 443 |
+
detector that this region of memory need not be traced. — *end note*]
|
| 444 |
|
| 445 |
*Throws:* Nothing.
|
| 446 |
|
| 447 |
+
[*Note 4*: Under some conditions implementations may need to allocate
|
| 448 |
+
memory. However, the request can be ignored if memory allocation
|
| 449 |
+
fails. — *end note*]
|
| 450 |
|
| 451 |
``` cpp
|
| 452 |
void undeclare_no_pointers(char* p, size_t n);
|
| 453 |
```
|
| 454 |
|
|
|
|
| 464 |
``` cpp
|
| 465 |
pointer_safety get_pointer_safety() noexcept;
|
| 466 |
```
|
| 467 |
|
| 468 |
*Returns:* `pointer_safety::strict` if the implementation has strict
|
| 469 |
+
pointer safety ([[basic.stc.dynamic.safety]]). It is
|
| 470 |
+
*implementation-defined* whether `get_pointer_safety` returns
|
| 471 |
+
`pointer_safety::relaxed` or `pointer_safety::preferred` if the
|
| 472 |
+
implementation has relaxed pointer safety.[^1]
|
| 473 |
|
| 474 |
### Align <a id="ptr.align">[[ptr.align]]</a>
|
| 475 |
|
| 476 |
``` cpp
|
| 477 |
+
void* align(size_t alignment, size_t size, void*& ptr, size_t& space);
|
|
|
|
| 478 |
```
|
| 479 |
|
| 480 |
*Effects:* If it is possible to fit `size` bytes of storage aligned by
|
| 481 |
`alignment` into the buffer pointed to by `ptr` with length `space`, the
|
| 482 |
+
function updates `ptr` to represent the first possible address of such
|
| 483 |
storage and decreases `space` by the number of bytes used for alignment.
|
| 484 |
Otherwise, the function does nothing.
|
| 485 |
|
| 486 |
*Requires:*
|
| 487 |
|
| 488 |
+
- `alignment` shall be a power of two
|
| 489 |
+
- `ptr` shall represent the address of contiguous storage of at least
|
| 490 |
+
`space` bytes
|
| 491 |
|
| 492 |
*Returns:* A null pointer if the requested aligned buffer would not fit
|
| 493 |
into the available space, otherwise the adjusted value of `ptr`.
|
| 494 |
|
| 495 |
+
[*Note 1*: The function updates its `ptr` and `space` arguments so that
|
| 496 |
+
it can be called repeatedly with possibly different `alignment` and
|
| 497 |
+
`size` arguments for the same buffer. — *end note*]
|
| 498 |
|
| 499 |
### Allocator argument tag <a id="allocator.tag">[[allocator.tag]]</a>
|
| 500 |
|
| 501 |
``` cpp
|
| 502 |
namespace std {
|
| 503 |
+
struct allocator_arg_t { explicit allocator_arg_t() = default; };
|
| 504 |
+
inline constexpr allocator_arg_t allocator_arg{};
|
| 505 |
}
|
| 506 |
```
|
| 507 |
|
| 508 |
The `allocator_arg_t` struct is an empty structure type used as a unique
|
| 509 |
type to disambiguate constructor and function overloading. Specifically,
|
|
|
|
| 518 |
|
| 519 |
``` cpp
|
| 520 |
template <class T, class Alloc> struct uses_allocator;
|
| 521 |
```
|
| 522 |
|
| 523 |
+
*Remarks:* Automatically detects whether `T` has a nested
|
| 524 |
+
`allocator_type` that is convertible from `Alloc`. Meets the
|
| 525 |
+
`BinaryTypeTrait` requirements ([[meta.rqmts]]). The implementation
|
| 526 |
+
shall provide a definition that is derived from `true_type` if the
|
| 527 |
+
*qualified-id* `T::allocator_type` is valid and denotes a
|
| 528 |
+
type ([[temp.deduct]]) and
|
| 529 |
+
`is_convertible_v<Alloc, T::allocator_type> != false`, otherwise it
|
| 530 |
shall be derived from `false_type`. A program may specialize this
|
| 531 |
template to derive from `true_type` for a user-defined type `T` that
|
| 532 |
does not have a nested `allocator_type` but nonetheless can be
|
| 533 |
constructed with an allocator where either:
|
| 534 |
|
| 535 |
- the first argument of a constructor has type `allocator_arg_t` and the
|
| 536 |
second argument has type `Alloc` or
|
| 537 |
- the last argument of a constructor has type `Alloc`.
|
| 538 |
|
| 539 |
+
#### Uses-allocator construction <a id="allocator.uses.construction">[[allocator.uses.construction]]</a>
|
| 540 |
|
| 541 |
*Uses-allocator construction* with allocator `Alloc` refers to the
|
| 542 |
construction of an object `obj` of type `T`, using constructor arguments
|
| 543 |
`v1, v2, ..., vN` of types `V1, V2, ..., VN`, respectively, and an
|
| 544 |
allocator `alloc` of type `Alloc`, according to the following rules:
|
| 545 |
|
| 546 |
+
- if `uses_allocator_v<T, Alloc>` is `false` and
|
| 547 |
+
`is_constructible_v<T, V1, V2, ..., VN>` is `true`, then `obj` is
|
| 548 |
initialized as `obj(v1, v2, ..., vN)`;
|
| 549 |
+
- otherwise, if `uses_allocator_v<T, Alloc>` is `true` and
|
| 550 |
+
`is_constructible_v<T, allocator_arg_t, Alloc,` `V1, V2, ..., VN>` is
|
| 551 |
+
`true`, then `obj` is initialized as `obj(allocator_arg, alloc, v1,
|
|
|
|
| 552 |
v2, ..., vN)`;
|
| 553 |
+
- otherwise, if `uses_allocator_v<T, Alloc>` is `true` and
|
| 554 |
+
`is_constructible_v<T, V1, V2, ..., VN, Alloc>` is `true`, then `obj`
|
| 555 |
+
is initialized as `obj(v1, v2, ..., vN, alloc)`;
|
| 556 |
- otherwise, the request for uses-allocator construction is ill-formed.
|
| 557 |
+
\[*Note 1*: An error will result if `uses_allocator_v<T, Alloc>` is
|
| 558 |
+
`true` but the specific constructor does not take an allocator. This
|
| 559 |
definition prevents a silent failure to pass the allocator to an
|
| 560 |
+
element. — *end note*]
|
| 561 |
|
| 562 |
### Allocator traits <a id="allocator.traits">[[allocator.traits]]</a>
|
| 563 |
|
| 564 |
The class template `allocator_traits` supplies a uniform interface to
|
| 565 |
all allocator types. An allocator cannot be a non-class type, however,
|
| 566 |
+
even if `allocator_traits` supplies the entire required interface.
|
| 567 |
+
|
| 568 |
+
[*Note 1*: Thus, it is always possible to create a derived class from
|
| 569 |
+
an allocator. — *end note*]
|
| 570 |
|
| 571 |
``` cpp
|
| 572 |
namespace std {
|
| 573 |
template <class Alloc> struct allocator_traits {
|
| 574 |
+
using allocator_type = Alloc;
|
| 575 |
|
| 576 |
+
using value_type = typename Alloc::value_type;
|
| 577 |
|
| 578 |
+
using pointer = see below;
|
| 579 |
+
using const_pointer = see below;
|
| 580 |
+
using void_pointer = see below;
|
| 581 |
+
using const_void_pointer = see below;
|
| 582 |
|
| 583 |
+
using difference_type = see below;
|
| 584 |
+
using size_type = see below;
|
| 585 |
|
| 586 |
+
using propagate_on_container_copy_assignment = see below;
|
| 587 |
+
using propagate_on_container_move_assignment = see below;
|
| 588 |
+
using propagate_on_container_swap = see below;
|
| 589 |
+
using is_always_equal = see below;
|
| 590 |
|
| 591 |
template <class T> using rebind_alloc = see below;
|
| 592 |
template <class T> using rebind_traits = allocator_traits<rebind_alloc<T>>;
|
| 593 |
|
| 594 |
static pointer allocate(Alloc& a, size_type n);
|
|
|
|
| 610 |
```
|
| 611 |
|
| 612 |
#### Allocator traits member types <a id="allocator.traits.types">[[allocator.traits.types]]</a>
|
| 613 |
|
| 614 |
``` cpp
|
| 615 |
+
using pointer = see below;
|
| 616 |
```
|
| 617 |
|
| 618 |
+
*Type:* `Alloc::pointer` if the *qualified-id* `Alloc::pointer` is valid
|
| 619 |
+
and denotes a type ([[temp.deduct]]); otherwise, `value_type*`.
|
| 620 |
|
| 621 |
``` cpp
|
| 622 |
+
using const_pointer = see below;
|
| 623 |
```
|
| 624 |
|
| 625 |
+
*Type:* `Alloc::const_pointer` if the *qualified-id*
|
| 626 |
+
`Alloc::const_pointer` is valid and denotes a type ([[temp.deduct]]);
|
| 627 |
+
otherwise, `pointer_traits<pointer>::rebind<const value_type>`.
|
| 628 |
|
| 629 |
``` cpp
|
| 630 |
+
using void_pointer = see below;
|
| 631 |
```
|
| 632 |
|
| 633 |
+
*Type:* `Alloc::void_pointer` if the *qualified-id*
|
| 634 |
+
`Alloc::void_pointer` is valid and denotes a type ([[temp.deduct]]);
|
| 635 |
+
otherwise, `pointer_traits<pointer>::rebind<void>`.
|
| 636 |
|
| 637 |
``` cpp
|
| 638 |
+
using const_void_pointer = see below;
|
| 639 |
```
|
| 640 |
|
| 641 |
+
*Type:* `Alloc::const_void_pointer` if the *qualified-id*
|
| 642 |
+
`Alloc::const_void_pointer` is valid and denotes a
|
| 643 |
+
type ([[temp.deduct]]); otherwise,
|
| 644 |
`pointer_traits<pointer>::rebind<const void>`.
|
| 645 |
|
| 646 |
``` cpp
|
| 647 |
+
using difference_type = see below;
|
| 648 |
```
|
| 649 |
|
| 650 |
+
*Type:* `Alloc::difference_type` if the *qualified-id*
|
| 651 |
+
`Alloc::difference_type` is valid and denotes a type ([[temp.deduct]]);
|
| 652 |
+
otherwise, `pointer_traits<pointer>::difference_type`.
|
| 653 |
|
| 654 |
``` cpp
|
| 655 |
+
using size_type = see below;
|
| 656 |
```
|
| 657 |
|
| 658 |
+
*Type:* `Alloc::size_type` if the *qualified-id* `Alloc::size_type` is
|
| 659 |
+
valid and denotes a type ([[temp.deduct]]); otherwise,
|
| 660 |
`make_unsigned_t<difference_type>`.
|
| 661 |
|
| 662 |
``` cpp
|
| 663 |
+
using propagate_on_container_copy_assignment = see below;
|
| 664 |
```
|
| 665 |
|
| 666 |
+
*Type:* `Alloc::propagate_on_container_copy_assignment` if the
|
| 667 |
+
*qualified-id* `Alloc::propagate_on_container_copy_assignment` is valid
|
| 668 |
+
and denotes a type ([[temp.deduct]]); otherwise `false_type`.
|
| 669 |
|
| 670 |
``` cpp
|
| 671 |
+
using propagate_on_container_move_assignment = see below;
|
| 672 |
```
|
| 673 |
|
| 674 |
+
*Type:* `Alloc::propagate_on_container_move_assignment` if the
|
| 675 |
+
*qualified-id* `Alloc::propagate_on_container_move_assignment` is valid
|
| 676 |
+
and denotes a type ([[temp.deduct]]); otherwise `false_type`.
|
| 677 |
|
| 678 |
``` cpp
|
| 679 |
+
using propagate_on_container_swap = see below;
|
| 680 |
```
|
| 681 |
|
| 682 |
+
*Type:* `Alloc::propagate_on_container_swap` if the *qualified-id*
|
| 683 |
+
`Alloc::propagate_on_container_swap` is valid and denotes a
|
| 684 |
+
type ([[temp.deduct]]); otherwise `false_type`.
|
| 685 |
+
|
| 686 |
+
``` cpp
|
| 687 |
+
using is_always_equal = see below;
|
| 688 |
+
```
|
| 689 |
+
|
| 690 |
+
*Type:* `Alloc::is_always_equal` if the *qualified-id*
|
| 691 |
+
`Alloc::is_always_equal` is valid and denotes a type ([[temp.deduct]]);
|
| 692 |
+
otherwise `is_empty<Alloc>::type`.
|
| 693 |
|
| 694 |
``` cpp
|
| 695 |
template <class T> using rebind_alloc = see below;
|
| 696 |
```
|
| 697 |
|
| 698 |
+
*Alias template:* `Alloc::rebind<T>::other` if the *qualified-id*
|
| 699 |
+
`Alloc::rebind<T>::other` is valid and denotes a
|
| 700 |
+
type ([[temp.deduct]]); otherwise, `Alloc<T, Args>` if `Alloc` is a
|
| 701 |
+
class template instantiation of the form `Alloc<U, Args>`, where `Args`
|
| 702 |
+
is zero or more type arguments; otherwise, the instantiation of
|
| 703 |
+
`rebind_alloc` is ill-formed.
|
| 704 |
|
| 705 |
#### Allocator traits static member functions <a id="allocator.traits.members">[[allocator.traits.members]]</a>
|
| 706 |
|
| 707 |
``` cpp
|
| 708 |
static pointer allocate(Alloc& a, size_type n);
|
|
|
|
| 719 |
|
| 720 |
``` cpp
|
| 721 |
static void deallocate(Alloc& a, pointer p, size_type n);
|
| 722 |
```
|
| 723 |
|
| 724 |
+
*Effects:* Calls `a.deallocate(p, n)`.
|
| 725 |
|
| 726 |
*Throws:* Nothing.
|
| 727 |
|
| 728 |
``` cpp
|
| 729 |
template <class T, class... Args>
|
| 730 |
static void construct(Alloc& a, T* p, Args&&... args);
|
| 731 |
```
|
| 732 |
|
| 733 |
+
*Effects:* Calls `a.construct(p, std::forward<Args>(args)...)` if that
|
| 734 |
call is well-formed; otherwise, invokes
|
| 735 |
`::new (static_cast<void*>(p)) T(std::forward<Args>(args)...)`.
|
| 736 |
|
| 737 |
``` cpp
|
| 738 |
template <class T>
|
| 739 |
static void destroy(Alloc& a, T* p);
|
| 740 |
```
|
| 741 |
|
| 742 |
+
*Effects:* Calls `a.destroy(p)` if that call is well-formed; otherwise,
|
| 743 |
invokes `p->~T()`.
|
| 744 |
|
| 745 |
``` cpp
|
| 746 |
static size_type max_size(const Alloc& a) noexcept;
|
| 747 |
```
|
| 748 |
|
| 749 |
*Returns:* `a.max_size()` if that expression is well-formed; otherwise,
|
| 750 |
+
`numeric_limits<size_type>::max()/sizeof(value_type)`.
|
| 751 |
|
| 752 |
``` cpp
|
| 753 |
static Alloc select_on_container_copy_construction(const Alloc& rhs);
|
| 754 |
```
|
| 755 |
|
| 756 |
*Returns:* `rhs.select_on_container_copy_construction()` if that
|
| 757 |
expression is well-formed; otherwise, `rhs`.
|
| 758 |
|
| 759 |
### The default allocator <a id="default.allocator">[[default.allocator]]</a>
|
| 760 |
|
| 761 |
+
All specializations of the default allocator satisfy the allocator
|
| 762 |
+
completeness requirements ([[allocator.requirements.completeness]]).
|
| 763 |
+
|
| 764 |
``` cpp
|
| 765 |
namespace std {
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 766 |
template <class T> class allocator {
|
| 767 |
public:
|
| 768 |
+
using value_type = T;
|
| 769 |
+
using propagate_on_container_move_assignment = true_type;
|
| 770 |
+
using is_always_equal = true_type;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 771 |
|
| 772 |
allocator() noexcept;
|
| 773 |
allocator(const allocator&) noexcept;
|
| 774 |
template <class U> allocator(const allocator<U>&) noexcept;
|
| 775 |
~allocator();
|
| 776 |
|
| 777 |
+
T* allocate(size_t n);
|
| 778 |
+
void deallocate(T* p, size_t n);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 779 |
};
|
| 780 |
}
|
| 781 |
```
|
| 782 |
|
| 783 |
#### `allocator` members <a id="allocator.members">[[allocator.members]]</a>
|
|
|
|
| 788 |
to these functions that allocate or deallocate a particular unit of
|
| 789 |
storage shall occur in a single total order, and each such deallocation
|
| 790 |
call shall happen before the next allocation (if any) in this order.
|
| 791 |
|
| 792 |
``` cpp
|
| 793 |
+
T* allocate(size_t n);
|
| 794 |
```
|
| 795 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
| 796 |
*Returns:* A pointer to the initial element of an array of storage of
|
| 797 |
size `n` `* sizeof(T)`, aligned appropriately for objects of type `T`.
|
|
|
|
|
|
|
| 798 |
|
| 799 |
+
*Remarks:* the storage is obtained by calling
|
| 800 |
+
`::operator new` ([[new.delete]]), but it is unspecified when or how
|
| 801 |
+
often this function is called.
|
|
|
|
|
|
|
| 802 |
|
| 803 |
*Throws:* `bad_alloc` if the storage cannot be obtained.
|
| 804 |
|
| 805 |
``` cpp
|
| 806 |
+
void deallocate(T* p, size_t n);
|
| 807 |
```
|
| 808 |
|
| 809 |
*Requires:* `p` shall be a pointer value obtained from `allocate()`. `n`
|
| 810 |
shall equal the value passed as the first argument to the invocation of
|
| 811 |
allocate which returned `p`.
|
| 812 |
|
| 813 |
*Effects:* Deallocates the storage referenced by `p` .
|
| 814 |
|
| 815 |
+
*Remarks:* Uses `::operator delete` ([[new.delete]]), but it is
|
|
|
|
| 816 |
unspecified when this function is called.
|
| 817 |
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|
| 818 |
#### `allocator` globals <a id="allocator.globals">[[allocator.globals]]</a>
|
| 819 |
|
| 820 |
``` cpp
|
| 821 |
+
template <class T, class U>
|
| 822 |
+
bool operator==(const allocator<T>&, const allocator<U>&) noexcept;
|
| 823 |
```
|
| 824 |
|
| 825 |
*Returns:* `true`.
|
| 826 |
|
| 827 |
``` cpp
|
| 828 |
+
template <class T, class U>
|
| 829 |
+
bool operator!=(const allocator<T>&, const allocator<U>&) noexcept;
|
| 830 |
```
|
| 831 |
|
| 832 |
*Returns:* `false`.
|
| 833 |
|
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|
| 834 |
### Specialized algorithms <a id="specialized.algorithms">[[specialized.algorithms]]</a>
|
| 835 |
|
| 836 |
+
Throughout this subclause, the names of template parameters are used to
|
| 837 |
+
express type requirements.
|
| 838 |
+
|
| 839 |
+
- If an algorithm’s template parameter is named `InputIterator`, the
|
| 840 |
+
template argument shall satisfy the requirements of an input
|
| 841 |
+
iterator ([[input.iterators]]).
|
| 842 |
+
- If an algorithm’s template parameter is named `ForwardIterator`, the
|
| 843 |
+
template argument shall satisfy the requirements of a forward
|
| 844 |
+
iterator ([[forward.iterators]]), and is required to have the
|
| 845 |
property that no exceptions are thrown from increment, assignment,
|
| 846 |
+
comparison, or indirection through valid iterators.
|
| 847 |
+
|
| 848 |
+
Unless otherwise specified, if an exception is thrown in the following
|
| 849 |
+
algorithms there are no effects.
|
| 850 |
|
| 851 |
#### `addressof` <a id="specialized.addressof">[[specialized.addressof]]</a>
|
| 852 |
|
| 853 |
``` cpp
|
| 854 |
+
template <class T> constexpr T* addressof(T& r) noexcept;
|
| 855 |
```
|
| 856 |
|
| 857 |
*Returns:* The actual address of the object or function referenced by
|
| 858 |
`r`, even in the presence of an overloaded `operator&`.
|
| 859 |
|
| 860 |
+
*Remarks:* An expression `addressof(E)` is a constant
|
| 861 |
+
subexpression ([[defns.const.subexpr]]) if `E` is an lvalue constant
|
| 862 |
+
subexpression.
|
| 863 |
+
|
| 864 |
+
#### `uninitialized_default_construct` <a id="uninitialized.construct.default">[[uninitialized.construct.default]]</a>
|
| 865 |
+
|
| 866 |
+
``` cpp
|
| 867 |
+
template <class ForwardIterator>
|
| 868 |
+
void uninitialized_default_construct(ForwardIterator first, ForwardIterator last);
|
| 869 |
+
```
|
| 870 |
+
|
| 871 |
+
*Effects:* Equivalent to:
|
| 872 |
+
|
| 873 |
+
``` cpp
|
| 874 |
+
for (; first != last; ++first)
|
| 875 |
+
::new (static_cast<void*>(addressof(*first)))
|
| 876 |
+
typename iterator_traits<ForwardIterator>::value_type;
|
| 877 |
+
```
|
| 878 |
+
|
| 879 |
+
``` cpp
|
| 880 |
+
template <class ForwardIterator, class Size>
|
| 881 |
+
ForwardIterator uninitialized_default_construct_n(ForwardIterator first, Size n);
|
| 882 |
+
```
|
| 883 |
+
|
| 884 |
+
*Effects:* Equivalent to:
|
| 885 |
+
|
| 886 |
+
``` cpp
|
| 887 |
+
for (; n>0; (void)++first, --n)
|
| 888 |
+
::new (static_cast<void*>(addressof(*first)))
|
| 889 |
+
typename iterator_traits<ForwardIterator>::value_type;
|
| 890 |
+
return first;
|
| 891 |
+
```
|
| 892 |
+
|
| 893 |
+
#### `uninitialized_value_construct` <a id="uninitialized.construct.value">[[uninitialized.construct.value]]</a>
|
| 894 |
+
|
| 895 |
+
``` cpp
|
| 896 |
+
template <class ForwardIterator>
|
| 897 |
+
void uninitialized_value_construct(ForwardIterator first, ForwardIterator last);
|
| 898 |
+
```
|
| 899 |
+
|
| 900 |
+
*Effects:* Equivalent to:
|
| 901 |
+
|
| 902 |
+
``` cpp
|
| 903 |
+
for (; first != last; ++first)
|
| 904 |
+
::new (static_cast<void*>(addressof(*first)))
|
| 905 |
+
typename iterator_traits<ForwardIterator>::value_type();
|
| 906 |
+
```
|
| 907 |
+
|
| 908 |
+
``` cpp
|
| 909 |
+
template <class ForwardIterator, class Size>
|
| 910 |
+
ForwardIterator uninitialized_value_construct_n(ForwardIterator first, Size n);
|
| 911 |
+
```
|
| 912 |
+
|
| 913 |
+
*Effects:* Equivalent to:
|
| 914 |
+
|
| 915 |
+
``` cpp
|
| 916 |
+
for (; n>0; (void)++first, --n)
|
| 917 |
+
::new (static_cast<void*>(addressof(*first)))
|
| 918 |
+
typename iterator_traits<ForwardIterator>::value_type();
|
| 919 |
+
return first;
|
| 920 |
+
```
|
| 921 |
+
|
| 922 |
#### `uninitialized_copy` <a id="uninitialized.copy">[[uninitialized.copy]]</a>
|
| 923 |
|
| 924 |
``` cpp
|
| 925 |
template <class InputIterator, class ForwardIterator>
|
| 926 |
ForwardIterator uninitialized_copy(InputIterator first, InputIterator last,
|
| 927 |
ForwardIterator result);
|
| 928 |
```
|
| 929 |
|
| 930 |
+
*Effects:* As if by:
|
| 931 |
|
| 932 |
``` cpp
|
| 933 |
+
for (; first != last; ++result, (void) ++first)
|
| 934 |
+
::new (static_cast<void*>(addressof(*result)))
|
| 935 |
typename iterator_traits<ForwardIterator>::value_type(*first);
|
| 936 |
```
|
| 937 |
|
| 938 |
+
*Returns:* `result`.
|
| 939 |
|
| 940 |
``` cpp
|
| 941 |
template <class InputIterator, class Size, class ForwardIterator>
|
| 942 |
ForwardIterator uninitialized_copy_n(InputIterator first, Size n,
|
| 943 |
ForwardIterator result);
|
| 944 |
```
|
| 945 |
|
| 946 |
+
*Effects:* As if by:
|
| 947 |
|
| 948 |
``` cpp
|
| 949 |
+
for ( ; n > 0; ++result, (void) ++first, --n) {
|
| 950 |
+
::new (static_cast<void*>(addressof(*result)))
|
| 951 |
typename iterator_traits<ForwardIterator>::value_type(*first);
|
| 952 |
}
|
| 953 |
```
|
| 954 |
|
| 955 |
+
*Returns:* `result`.
|
| 956 |
+
|
| 957 |
+
#### `uninitialized_move` <a id="uninitialized.move">[[uninitialized.move]]</a>
|
| 958 |
+
|
| 959 |
+
``` cpp
|
| 960 |
+
template <class InputIterator, class ForwardIterator>
|
| 961 |
+
ForwardIterator uninitialized_move(InputIterator first, InputIterator last,
|
| 962 |
+
ForwardIterator result);
|
| 963 |
+
```
|
| 964 |
+
|
| 965 |
+
*Effects:* Equivalent to:
|
| 966 |
+
|
| 967 |
+
``` cpp
|
| 968 |
+
for (; first != last; (void)++result, ++first)
|
| 969 |
+
::new (static_cast<void*>(addressof(*result)))
|
| 970 |
+
typename iterator_traits<ForwardIterator>::value_type(std::move(*first));
|
| 971 |
+
return result;
|
| 972 |
+
```
|
| 973 |
+
|
| 974 |
+
*Remarks:* If an exception is thrown, some objects in the range
|
| 975 |
+
\[`first`, `last`) are left in a valid but unspecified state.
|
| 976 |
+
|
| 977 |
+
``` cpp
|
| 978 |
+
template <class InputIterator, class Size, class ForwardIterator>
|
| 979 |
+
pair<InputIterator, ForwardIterator>
|
| 980 |
+
uninitialized_move_n(InputIterator first, Size n, ForwardIterator result);
|
| 981 |
+
```
|
| 982 |
+
|
| 983 |
+
*Effects:* Equivalent to:
|
| 984 |
+
|
| 985 |
+
``` cpp
|
| 986 |
+
for (; n > 0; ++result, (void) ++first, --n)
|
| 987 |
+
::new (static_cast<void*>(addressof(*result)))
|
| 988 |
+
typename iterator_traits<ForwardIterator>::value_type(std::move(*first));
|
| 989 |
+
return {first,result};
|
| 990 |
+
```
|
| 991 |
+
|
| 992 |
+
*Remarks:* If an exception is thrown, some objects in the range
|
| 993 |
+
\[`first`, `std::next(first,n)`) are left in a valid but unspecified
|
| 994 |
+
state.
|
| 995 |
|
| 996 |
#### `uninitialized_fill` <a id="uninitialized.fill">[[uninitialized.fill]]</a>
|
| 997 |
|
| 998 |
``` cpp
|
| 999 |
template <class ForwardIterator, class T>
|
| 1000 |
void uninitialized_fill(ForwardIterator first, ForwardIterator last,
|
| 1001 |
const T& x);
|
| 1002 |
```
|
| 1003 |
|
| 1004 |
+
*Effects:* As if by:
|
| 1005 |
|
| 1006 |
``` cpp
|
| 1007 |
for (; first != last; ++first)
|
| 1008 |
+
::new (static_cast<void*>(addressof(*first)))
|
| 1009 |
typename iterator_traits<ForwardIterator>::value_type(x);
|
| 1010 |
```
|
| 1011 |
|
|
|
|
|
|
|
| 1012 |
``` cpp
|
| 1013 |
template <class ForwardIterator, class Size, class T>
|
| 1014 |
ForwardIterator uninitialized_fill_n(ForwardIterator first, Size n, const T& x);
|
| 1015 |
```
|
| 1016 |
|
| 1017 |
+
*Effects:* As if by:
|
| 1018 |
|
| 1019 |
``` cpp
|
| 1020 |
for (; n--; ++first)
|
| 1021 |
+
::new (static_cast<void*>(addressof(*first)))
|
| 1022 |
typename iterator_traits<ForwardIterator>::value_type(x);
|
| 1023 |
return first;
|
| 1024 |
```
|
| 1025 |
|
| 1026 |
+
#### `destroy` <a id="specialized.destroy">[[specialized.destroy]]</a>
|
| 1027 |
|
| 1028 |
+
``` cpp
|
| 1029 |
+
template <class T>
|
| 1030 |
+
void destroy_at(T* location);
|
| 1031 |
+
```
|
| 1032 |
|
| 1033 |
+
*Effects:* Equivalent to:
|
|
|
|
| 1034 |
|
| 1035 |
+
``` cpp
|
| 1036 |
+
location->~T();
|
| 1037 |
+
```
|
| 1038 |
|
| 1039 |
+
``` cpp
|
| 1040 |
+
template <class ForwardIterator>
|
| 1041 |
+
void destroy(ForwardIterator first, ForwardIterator last);
|
| 1042 |
+
```
|
| 1043 |
|
| 1044 |
+
*Effects:* Equivalent to:
|
| 1045 |
|
| 1046 |
+
``` cpp
|
| 1047 |
+
for (; first!=last; ++first)
|
| 1048 |
+
destroy_at(addressof(*first));
|
| 1049 |
+
```
|
| 1050 |
+
|
| 1051 |
+
``` cpp
|
| 1052 |
+
template <class ForwardIterator, class Size>
|
| 1053 |
+
ForwardIterator destroy_n(ForwardIterator first, Size n);
|
| 1054 |
+
```
|
| 1055 |
+
|
| 1056 |
+
*Effects:* Equivalent to:
|
| 1057 |
+
|
| 1058 |
+
``` cpp
|
| 1059 |
+
for (; n > 0; (void)++first, --n)
|
| 1060 |
+
destroy_at(addressof(*first));
|
| 1061 |
+
return first;
|
| 1062 |
+
```
|
| 1063 |
+
|
| 1064 |
+
### C library memory allocation <a id="c.malloc">[[c.malloc]]</a>
|
| 1065 |
+
|
| 1066 |
+
[*Note 1*: The header `<cstdlib>` ([[cstdlib.syn]]) declares the
|
| 1067 |
+
functions described in this subclause. — *end note*]
|
| 1068 |
+
|
| 1069 |
+
``` cpp
|
| 1070 |
+
void* aligned_alloc(size_t alignment, size_t size);
|
| 1071 |
+
void* calloc(size_t nmemb, size_t size);
|
| 1072 |
+
void* malloc(size_t size);
|
| 1073 |
+
void* realloc(void* ptr, size_t size);
|
| 1074 |
+
```
|
| 1075 |
+
|
| 1076 |
+
*Effects:* These functions have the semantics specified in the C
|
| 1077 |
+
standard library.
|
| 1078 |
+
|
| 1079 |
+
*Remarks:* These functions do not attempt to allocate storage by calling
|
| 1080 |
+
`::operator new()` ([[support.dynamic]]).
|
| 1081 |
+
|
| 1082 |
+
Storage allocated directly with these functions is implicitly declared
|
| 1083 |
+
reachable (see [[basic.stc.dynamic.safety]]) on allocation, ceases to
|
| 1084 |
+
be declared reachable on deallocation, and need not cease to be declared
|
| 1085 |
+
reachable as the result of an `undeclare_reachable()` call.
|
| 1086 |
+
|
| 1087 |
+
[*Note 1*: This allows existing C libraries to remain unaffected by
|
| 1088 |
+
restrictions on pointers that are not safely derived, at the expense of
|
| 1089 |
+
providing far fewer garbage collection and leak detection options for
|
| 1090 |
+
`malloc()`-allocated objects. It also allows `malloc()` to be
|
| 1091 |
+
implemented with a separate allocation arena, bypassing the normal
|
| 1092 |
`declare_reachable()` implementation. The above functions should never
|
| 1093 |
intentionally be used as a replacement for `declare_reachable()`, and
|
| 1094 |
newly written code is strongly encouraged to treat memory allocated with
|
| 1095 |
+
these functions as though it were allocated with
|
| 1096 |
+
`operator new`. — *end note*]
|
| 1097 |
|
| 1098 |
+
``` cpp
|
| 1099 |
+
void free(void* ptr);
|
| 1100 |
+
```
|
| 1101 |
|
| 1102 |
+
*Effects:* This function has the semantics specified in the C standard
|
| 1103 |
+
library.
|
| 1104 |
|
| 1105 |
+
*Remarks:* This function does not attempt to deallocate storage by
|
| 1106 |
+
calling `::operator delete()`.
|
| 1107 |
+
|
| 1108 |
+
ISO C 7.22.3.
|
| 1109 |
|