std::allocator_traits<Alloc>::deallocate 定义于头文件<memory> staticvoiddeallocate(Alloc&a, pointer p, size_type n); (C++11 起) (C++20 前) staticconstexprvoiddeallocate(Alloc&a, pointer p, size_type n); (C++20 起) 用分配器a解分配p所引用的存储,通过调用a.deallocate(p, n) ...
std::allocator_traits<Alloc>::construct 定义于头文件<memory> template<classT,class...Args> staticvoidconstruct(Alloc&a, T*p, Args&&...args); (C++11 起) (C++20 前) template<classT,class...Args> staticconstexprvoidconstruct(Alloc&a, T*p, Args&&...args); ...
C++ 动态内存管理 std::allocator_traits 在标头 <memory> 定义 template< class T, class... Args > static void construct( Alloc& a, T* p, Args&&... args ); (C++11 起) (C++20 起为 constexpr) 若可能,则在 p 所指向的分配的未初始化存储构造 T 类型对象,通过调用 a.construct(p, std:...
std::allocator_traits<Alloc>::construct Defined in header<memory> template<classT,class...Args> staticvoidconstruct(Alloc&a, T*p, Args&&...args); (since C++11) (constexpr since C++20) If possible, constructs an object of typeTin allocated uninitialized storage pointed to byp, by callinga...
std::allocator_traits<Alloc>::deallocate C++ Dynamic memory management std::allocator_traits Defined in header<memory> staticvoiddeallocate(Alloc&a, pointer p, size_type n); (since C++11) (constexpr since C++20) Uses the allocatorato deallocate the storage referenced byp, by callinga.deallocate...
std::allocator_traits::allocate std::allocator_traits::allocate Defined in header <memory> static pointer allocate( Alloc& a, size_type n ); (1) (since C++11) static pointer allocate( Alloc& a, size_type n, const_void_pointer hint ); (2) (since C++11) 使用分配器a分配n*...
template<classAlloc> structallocator_traits; (C++11 起) allocator_traits类模板提供访问分配器(Allocator)各种属性的标准化方式。标准容器和其他标准库组件通过此模板访问分配器,这使得能以任何类类型为分配器,只要用户提供的std::allocator_traits特化实现所有要求的功能。
在自定义分配器中,一般不需要手动实现construct和destroy,因为标准库中的std::allocator_traits会处理这些工作。std::allocator_traits默认会使用placement new来调用对象的构造函数,并调用对象的析构函数。 相当于在CustomAllocator中增加以下函数: template<typenameU,typename...Args>voidconstruct(U*p,Args&&...args)...
{ using alloc_t = DebugAllocator<char>; using str_t = std::basic_string< char, std::char_traits<char>, alloc_t >; std::cout << "sizeof(std::string) : " << sizeof(str_t) << std::endl; str_t s{}; s += "1234567890"; s += "abcde"; std::cout << "capacity : "<...
在自定义分配器中,一般不需要手动实现construct和destroy,因为标准库中的std::allocator_traits会处理这些工作。std::allocator_traits默认会使用placement new来调用对象的构造函数,并调用对象的析构函数。 相当于在CustomAllocator中增加以下函数: template<typenameU,typename... Args>voidconstruct(U* p, Args&&......