标准库头文件 <memory_resource>
来自cppreference.com
此头文件是动态内存管理库的一部分。
类
| 定义于命名空间
pmr | |
| (C++17) |
以 std::memory_resource 构造，支持基于它的运行时多态的分配器 (类模板) |
| (C++17) |
一个抽象接口，用于各种封装内存资源的类 (类) |
| (C++17) |
一组池资源的构造函数选项 (类) |
| (C++17) |
线程安全的 std::pmr::memory_resource，用于管理具有不同块大小的池中的分配 (类) |
| (C++17) |
线程不安全的 std::pmr::memory_resource，用于管理具有不同块大小的池中的分配 (类) |
| (C++17) |
一种特殊用途的 std::pmr::memory_resource，仅在资源被销毁时才释放所分配内存 (类) |
函数
| 定义于命名空间
pmr | |
| (C++17) |
返回一个静态的程序范围 std::pmr::memory_resource，它使用全局 operator new 与 operator delete 分配和解分配内存 (函数) |
| (C++17) |
返回一个不进行任何分配的静态 std::pmr::memory_resource (函数) |
| (C++17) |
获取缺省 std::pmr::memory_resource (函数) |
| (C++17) |
设置缺省 std::pmr::memory_resource (函数) |
概要
namespace std::pmr { // 类 memory_resource class memory_resource; bool operator==(const memory_resource& a, const memory_resource& b) noexcept; bool operator!=(const memory_resource& a, const memory_resource& b) noexcept; // 类模板 polymorphic_allocator template <class Tp> class polymorphic_allocator; template <class T1, class T2> bool operator==(const polymorphic_allocator<T1>& a, const polymorphic_allocator<T2>& b) noexcept; template <class T1, class T2> bool operator!=(const polymorphic_allocator<T1>& a, const polymorphic_allocator<T2>& b) noexcept; // 全局内存资源 memory_resource* new_delete_resource() noexcept; memory_resource* null_memory_resource() noexcept; memory_resource* set_default_resource(memory_resource* r) noexcept; memory_resource* get_default_resource() noexcept; // 池资源类 struct pool_options; class synchronized_pool_resource; class unsynchronized_pool_resource; class monotonic_buffer_resource; }
类 std::pmr::memory_resource
class memory_resource { static constexpr size_t max_align = alignof(max_align_t); // 进用于阐释 public: virtual ~memory_resource(); void* allocate(size_t bytes, size_t alignment = max_align); void deallocate(void* p, size_t bytes, size_t alignment = max_align); bool is_equal(const memory_resource& other) const noexcept; private: virtual void* do_allocate(size_t bytes, size_t alignment) = 0; virtual void do_deallocate(void* p, size_t bytes, size_t alignment) = 0; virtual bool do_is_equal(const memory_resource& other) const noexcept = 0; };
类模板 std::pmr::polymorphic_allocator
template<class Tp = byte> class polymorphic_allocator { memory_resource* memory_rsrc; // 仅用于阐释 public: using value_type = Tp; // 构造函数 polymorphic_allocator() noexcept; polymorphic_allocator(memory_resource* r); polymorphic_allocator(const polymorphic_allocator& other) = default; template<class U> polymorphic_allocator(const polymorphic_allocator<U>& other) noexcept; polymorphic_allocator& operator=(const polymorphic_allocator& rhs) = delete; // 成员函数 [[nodiscard]] Tp* allocate(size_t n); void deallocate(Tp* p, size_t n); void* allocate_bytes(size_t nbytes, size_t alignment = alignof(max_align_t)); void deallocate_bytes(void* p, size_t nbytes, size_t alignment = alignof(max_align_t)); template<class T> T* allocate_object(size_t n = 1); template<class T> void deallocate_object(T* p, size_t n = 1); template<class T, class... CtorArgs> T* new_object(CtorArgs&&... ctor_args); template<class T> void delete_object(T* p); template<class T, class... Args> void construct(T* p, Args&&... args); template<class T> void destroy(T* p); polymorphic_allocator select_on_container_copy_construction() const; memory_resource* resource() const; };
类 std::pmr::pool_options
struct pool_options { size_t max_blocks_per_chunk = 0; size_t largest_required_pool_block = 0; };
类 std::pmr::synchronized_pool_resource
class synchronized_pool_resource : public memory_resource { public: synchronized_pool_resource(const pool_options& opts, memory_resource* upstream); synchronized_pool_resource() : synchronized_pool_resource(pool_options(), get_default_resource()) {} explicit synchronized_pool_resource(memory_resource* upstream) : synchronized_pool_resource(pool_options(), upstream) {} explicit synchronized_pool_resource(const pool_options& opts) : synchronized_pool_resource(opts, get_default_resource()) {} synchronized_pool_resource(const synchronized_pool_resource&) = delete; virtual ~synchronized_pool_resource(); synchronized_pool_resource& operator=(const synchronized_pool_resource&) = delete; void release(); memory_resource* upstream_resource() const; pool_options options() const; protected: void *do_allocate(size_t bytes, size_t alignment) override; void do_deallocate(void *p, size_t bytes, size_t alignment) override; bool do_is_equal(const memory_resource& other) const noexcept override; };
类 std::pmr::unsynchronized_pool_resource
class unsynchronized_pool_resource : public memory_resource { public: unsynchronized_pool_resource(const pool_options& opts, memory_resource* upstream); unsynchronized_pool_resource() : unsynchronized_pool_resource(pool_options(), get_default_resource()) {} explicit unsynchronized_pool_resource(memory_resource* upstream) : unsynchronized_pool_resource(pool_options(), upstream) {} explicit unsynchronized_pool_resource(const pool_options& opts) : unsynchronized_pool_resource(opts, get_default_resource()) {} unsynchronized_pool_resource(const unsynchronized_pool_resource&) = delete; virtual ~unsynchronized_pool_resource(); unsynchronized_pool_resource& operator=(const unsynchronized_pool_resource&) = delete; void release(); memory_resource *upstream_resource() const; pool_options options() const; protected: void* do_allocate(size_t bytes, size_t alignment) override; void do_deallocate(void* p, size_t bytes, size_t alignment) override; bool do_is_equal(const memory_resource& other) const noexcept override; };
类 std::pmr::monotonic_buffer_resource
class monotonic_buffer_resource : public memory_resource { memory_resource *upstream_rsrc; // 仅用于阐释 void *current_buffer; // 仅用于阐释 size_t next_buffer_size; // 仅用于阐释 public: explicit monotonic_buffer_resource(memory_resource *upstream); monotonic_buffer_resource(size_t initial_size, memory_resource *upstream); monotonic_buffer_resource(void *buffer, size_t buffer_size, memory_resource *upstream); monotonic_buffer_resource() : monotonic_buffer_resource(get_default_resource()) {} explicit monotonic_buffer_resource(size_t initial_size) : monotonic_buffer_resource(initial_size, get_default_resource()) {} monotonic_buffer_resource(void *buffer, size_t buffer_size) : monotonic_buffer_resource(buffer, buffer_size, get_default_resource()) {} monotonic_buffer_resource(const monotonic_buffer_resource&) = delete; virtual ~monotonic_buffer_resource(); monotonic_buffer_resource operator=(const monotonic_buffer_resource&) = delete; void release(); memory_resource* upstream_resource() const; protected: void* do_allocate(size_t bytes, size_t alignment) override; void do_deallocate(void* p, size_t bytes, size_t alignment) override; bool do_is_equal(const memory_resource& other) const noexcept override; };