operator==,!=(std::allocator)

 

C++

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自由（freestanding）與宿主（hosted）

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記憶體管理庫

voidify (僅作說明*) 未初始化記憶體演算法 uninitialized_copy uninitialized_fill uninitialized_move (C++17) uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) destroy (C++17) destroy_at (C++17) uninitialized_copy_n (C++11) uninitialized_fill_n uninitialized_move_n (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17) destroy_n (C++17) construct_at (C++20) 受約束的未初始化 記憶體演算法 ranges::uninitialized_copy (C++20) ranges::uninitialized_fill (C++20) ranges::uninitialized_move (C++20) ranges::construct_at (C++20) ranges::destroy (C++20) ranges::destroy_n (C++20) ranges::destroy_at (C++20) ranges::uninitialized_copy_n (C++20) ranges::uninitialized_fill_n (C++20) ranges::uninitialized_move_n (C++20) ranges::uninitialized_default_construct (C++20) ranges::uninitialized_value_construct (C++20) ranges::uninitialized_default_construct_n (C++20)  ranges::uninitialized_value_construct_n (C++20) C 庫 malloc calloc realloc aligned_alloc (C++17) free

分配器 allocator allocator_traits (C++11) allocation_result (C++23) allocator_arg (C++11) uses_allocator (C++11) uses_allocator_construction_args (C++20) make_obj_using_allocator (C++20) uninitialized_construct_using_allocator (C++20)  scoped_allocator_adaptor (C++11) pmr::polymorphic_allocator (C++17) 記憶體資源 pmr::memory_resource (C++17) pmr::get_default_resource (C++17) pmr::set_default_resource (C++17) pmr::new_delete_resource (C++17) pmr::null_memory_resource (C++17) pmr::synchronized_pool_resource (C++17) pmr::unsynchronized_pool_resource (C++17) pmr::monotonic_buffer_resource (C++17) pmr::pool_options (C++17) 垃圾回收支援 declare_reachable (C++11)(直到 C++23) undeclare_reachable (C++11)(直到 C++23) declare_no_pointers (C++11)(直到 C++23) undeclare_no_pointers (C++11)(直到 C++23) pointer_safety (C++11)(直到 C++23) get_pointer_safety (C++11)(直到 C++23) 未初始化儲存 raw_storage_iterator (直到 C++20*) get_temporary_buffer (直到 C++20*) return_temporary_buffer (直到 C++20*) 顯式生命週期管理 start_lifetime_asstart_lifetime_as_array (C++23)(C++23)

智慧指標 unique_ptr (C++11) shared_ptr (C++11) weak_ptr (C++11) auto_ptr (直到 C++17*) owner_less (C++11) owner_less<void> (C++17) owner_hash (C++26) owner_equal (C++26) enable_shared_from_this (C++11) bad_weak_ptr (C++11) default_delete (C++11) out_ptr_t (C++23) inout_ptr_t (C++23) 低階記憶體 管理 operator new operator new[] operator delete operator delete[] get_new_handler (C++11) set_new_handler launder (C++17) bad_alloc bad_array_new_length (C++11) nothrow_t align_val_t (C++17) destroying_delete_t (C++20) new_handler nothrow 雜項 pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) is_sufficiently_aligned (C++26)

 

std::allocator

成員函式

建構函式

解構函式

address (C++20 前)

allocate

allocate_at_least (C++23)

deallocate

max_size (C++20 前)

construct (C++20 前)

destroy (C++20 前)

非成員函式

operator==operator!= (C++20 前)

 

	(1)
template< class T1, class T2 > bool operator==( const allocator<T1>& lhs, const allocator<T2>& rhs ) throw();			(C++11 前)
template< class T1, class T2 > bool operator==( const allocator<T1>& lhs, const allocator<T2>& rhs ) noexcept;			(C++11 起) (C++20 前)
template< class T1, class T2 > constexpr bool     operator==( const allocator<T1>& lhs, const allocator<T2>& rhs ) noexcept;			(C++20 起)
		(2)
template< class T1, class T2 > bool operator!=( const allocator<T1>& lhs, const allocator<T2>& rhs ) throw();				(C++11 前)
template< class T1, class T2 > bool operator!=( const allocator<T1>& lhs, const allocator<T2>& rhs ) noexcept;				(C++11 起) (C++20 前)

比較兩個預設分配器。因為預設分配器是無狀態的，所以兩個預設分配器始終相等。

1) 返回 true。

2) 返回 false。

!= 運算子由 operator== 合成。

(C++20 起)

引數

lhs, rhs

-

要比較的預設分配器

返回值

1) true

2) false