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

 

C++

编译器支持

独立和宿主

语言

标准库

标准库头文件

命名需求

功能测试宏 (C++20)

语言支持库

概念库 (C++20)

元编程库 (C++11)

诊断库

通用实用程序库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

本地化库

输入/输出库

文件系统库 (C++17)

正则表达式库 (C++11)

并发支持库 (C++11)

执行支持库 (C++26)

技术规范

符号索引

外部库

 

动态内存管理

未初始化内存算法 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) voidify (C++20) 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) 约束的未初始化内存算法 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) 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) 内存资源 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) 垃圾收集支持 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) 未初始化的存储 raw_storage_iterator (直到 C++20*) get_temporary_buffer (直到 C++20*) return_temporary_buffer (直到 C++20*) 显式生命周期管理 start_lifetime_asstart_lifetime_as_array (C++23)(C++23)

智能指针 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) 低级内存 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 其他 pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) C 库 malloc calloc realloc    aligned_alloc (C++17) free

 

std::allocator

成员函数

allocator::allocator

allocator::~allocator

allocator::address (直到 C++20)

allocator::allocate

allocator::allocate_at_least (C++23)

allocator::deallocate

allocator::max_size (直到 C++20)

allocator::construct (直到 C++20)

allocator::destroy (直到 C++20)

非成员函数

operator==operator!= (直到 C++20)

 

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

比较两个默认分配器。由于默认分配器是无状态的，因此两个默认分配器始终相等。

1) 返回 true.

2) 返回 false.

!= 运算符是 从 operator== 合成的。

(自 C++20 起)

参数

lhs, rhs

-

要比较的默认分配器

返回值

1) true

2) false