Memory management library - cppreference.com (original) (raw)
Memory management library
Contents
- 1 Smart pointers (since C++11)
- 2 Allocators
- 3 Memory resources (since C++17)
- 4 Uninitialized memory algorithms
- 5 Constrained uninitialized memory algorithms (since C++20)
- 6 Explicit lifetime management (since C++23)
- 7 Types for composite class design (since C++26)
- 8 Miscellaneous
- 9 Low level memory management
- 10 C-style memory management
- 11 Uninitialized storage (until C++20)
- 12 Garbage collector support (until C++23)
[edit] Smart pointers (since C++11)
Smart pointers enable automatic, exception-safe, object lifetime management.
| Defined in header | |
|---|---|
| Pointer categories | |
| unique_ptr(C++11) | smart pointer with unique object ownership semantics (class template) [edit] |
| shared_ptr(C++11) | smart pointer with shared object ownership semantics (class template) [edit] |
| weak_ptr(C++11) | weak reference to an object managed by std::shared_ptr (class template) [edit] |
| auto_ptr(deprecated in C++11)(removed in C++17) | smart pointer with strict object ownership semantics (class template) [edit] |
| Helper classes | |
| owner_less(C++11) | provides mixed-type owner-based ordering of shared and weak pointers (class template) [edit] |
| owner_hash(C++26) | provides owner-based hashing for shared and weak pointers (class) [edit] |
| owner_equal(C++26) | provides mixed-type owner-based equal comparisons of shared and weak pointers (class) [edit] |
| enable_shared_from_this(C++11) | allows an object to create a shared_ptr referring to itself (class template) [edit] |
| bad_weak_ptr(C++11) | exception thrown when accessing a weak_ptr which refers to already destroyed object (class) [edit] |
| default_delete(C++11) | default deleter for unique_ptr (class template) [edit] |
| Smart pointer adaptors (since C++23) | |
| out_ptr_t(C++23) | interoperates with foreign pointer setters and resets a smart pointer on destruction (class template) [edit] |
| out_ptr(C++23) | creates an out_ptr_t with an associated smart pointer and resetting arguments (function template) [edit] |
| inout_ptr_t(C++23) | interoperates with foreign pointer setters, obtains the initial pointer value from a smart pointer, and resets it on destruction (class template) [edit] |
| inout_ptr(C++23) | creates an inout_ptr_t with an associated smart pointer and resetting arguments (function template) [edit] |
[edit] Allocators
Allocators are class templates encapsulating memory allocation strategy. This allows generic containers to decouple memory management from the data itself.
| Defined in header | |
|---|---|
| allocator | the default allocator (class template) [edit] |
| allocator_traits(C++11) | provides information about allocator types (class template) [edit] |
| allocation_result(C++23) | records the address and the actual size of storage allocated by allocate_at_least (class template) [edit] |
| allocator_argallocator_arg_t(C++11) | a tag used to select allocator-aware constructors(tag)[edit] |
| uses_allocator(C++11) | checks if the specified type supports uses-allocator construction (class template) [edit] |
| uses_allocator_construction_args(C++20) | prepares the argument list matching the flavor of uses-allocator construction required by the given type (function template) [edit] |
| make_obj_using_allocator(C++20) | creates an object of the given type by means of uses-allocator construction (function template) [edit] |
| uninitialized_construct_using_allocator(C++20) | creates an object of the given type at specified memory location by means of uses-allocator construction (function template) [edit] |
| Defined in header <scoped_allocator> | |
| scoped_allocator_adaptor(C++11) | implements multi-level allocator for multi-level containers (class template) [edit] |
| Defined in header <memory_resource> | |
| Defined in namespace std::pmr | |
| polymorphic_allocator(C++17) | an allocator that supports run-time polymorphism based on the std::pmr::memory_resource it is constructed with (class template) [edit] |
[edit] Memory resources (since C++17)
Memory resources implement memory allocation strategies that can be used by std::pmr::polymorphic_allocator.
| Defined in header <memory_resource> | |
|---|---|
| Defined in namespace std::pmr | |
| memory_resource(C++17) | an abstract interface for classes that encapsulate memory resources (class) [edit] |
| new_delete_resource(C++17) | returns a static program-wide std::pmr::memory_resource that uses the global operator new and operator delete to allocate and deallocate memory (function) [edit] |
| null_memory_resource(C++17) | returns a static std::pmr::memory_resource that performs no allocation (function) [edit] |
| get_default_resource(C++17) | gets the default std::pmr::memory_resource (function) [edit] |
| set_default_resource(C++17) | sets the default std::pmr::memory_resource (function) [edit] |
| pool_options(C++17) | a set of constructor options for pool resources (class) [edit] |
| synchronized_pool_resource(C++17) | a thread-safe std::pmr::memory_resource for managing allocations in pools of different block sizes (class) [edit] |
| unsynchronized_pool_resource(C++17) | a thread-unsafe std::pmr::memory_resource for managing allocations in pools of different block sizes (class) [edit] |
| monotonic_buffer_resource(C++17) | a special-purpose std::pmr::memory_resource that releases the allocated memory only when the resource is destroyed (class) [edit] |
[edit] Uninitialized memory algorithms
| Defined in header | |
|---|---|
| uninitialized_copy | copies a range of objects to an uninitialized area of memory (function template) [edit] |
| uninitialized_copy_n(C++11) | copies a number of objects to an uninitialized area of memory (function template) [edit] |
| uninitialized_fill | copies an object to an uninitialized area of memory, defined by a range (function template) [edit] |
| uninitialized_fill_n | copies an object to an uninitialized area of memory, defined by a start and a count (function template) [edit] |
| uninitialized_move(C++17) | moves a range of objects to an uninitialized area of memory (function template) [edit] |
| uninitialized_move_n(C++17) | moves a number of objects to an uninitialized area of memory (function template) [edit] |
| uninitialized_default_construct(C++17) | constructs objects by default-initialization in an uninitialized area of memory, defined by a range (function template) [edit] |
| uninitialized_default_construct_n(C++17) | constructs objects by default-initialization in an uninitialized area of memory, defined by a start and a count (function template) [edit] |
| uninitialized_value_construct(C++17) | constructs objects by value-initialization in an uninitialized area of memory, defined by a range (function template) [edit] |
| uninitialized_value_construct_n(C++17) | constructs objects by value-initialization in an uninitialized area of memory, defined by a start and a count (function template) [edit] |
| destroy_at(C++17) | destroys an object at a given address (function template) [edit] |
| destroy(C++17) | destroys a range of objects (function template) [edit] |
| destroy_n(C++17) | destroys a number of objects in a range (function template) [edit] |
| construct_at(C++20) | creates an object at a given address (function template) [edit] |
[edit] Constrained uninitialized memory algorithms (since C++20)
C++20 provides constrained uninitialized memory algorithms that accept range arguments or iterator-sentinel pairs.
| Defined in header | |
|---|---|
| Defined in namespace std::ranges | |
| no-throw-input-iteratorno-throw-forward-iteratorno-throw-sentinel-forno-throw-input-rangeno-throw-forward-range(C++20) | specifies some operations on iterators, sentinels and ranges are non-throwing(exposition-only concept*) |
| ranges::uninitialized_copy(C++20) | copies a range of objects to an uninitialized area of memory(algorithm function object)[edit] |
| ranges::uninitialized_copy_n(C++20) | copies a number of objects to an uninitialized area of memory(algorithm function object)[edit] |
| ranges::uninitialized_fill(C++20) | copies an object to an uninitialized area of memory, defined by a range(algorithm function object)[edit] |
| ranges::uninitialized_fill_n(C++20) | copies an object to an uninitialized area of memory, defined by a start and a count(algorithm function object)[edit] |
| ranges::uninitialized_move(C++20) | moves a range of objects to an uninitialized area of memory(algorithm function object)[edit] |
| ranges::uninitialized_move_n(C++20) | moves a number of objects to an uninitialized area of memory(algorithm function object)[edit] |
| ranges::uninitialized_default_construct(C++20) | constructs objects by default-initialization in an uninitialized area of memory, defined by a range(algorithm function object)[edit] |
| ranges::uninitialized_default_construct_n(C++20) | constructs objects by default-initialization in an uninitialized area of memory, defined by a start and count(algorithm function object)[edit] |
| ranges::uninitialized_value_construct(C++20) | constructs objects by value-initialization in an uninitialized area of memory, defined by a range(algorithm function object)[edit] |
| ranges::uninitialized_value_construct_n(C++20) | constructs objects by value-initialization in an uninitialized area of memory, defined by a start and a count(algorithm function object)[edit] |
| ranges::destroy_at(C++20) | destroys an object at a given address(algorithm function object)[edit] |
| ranges::destroy(C++20) | destroys a range of objects(algorithm function object)[edit] |
| ranges::destroy_n(C++20) | destroys a number of objects in a range(algorithm function object)[edit] |
| ranges::construct_at(C++20) | creates an object at a given address(algorithm function object)[edit] |
[edit] Explicit lifetime management (since C++23)
[edit] Types for composite class design (since C++26)
[edit] Miscellaneous
| Defined in header | |
|---|---|
| pointer_traits(C++11) | provides information about pointer-like types (class template) [edit] |
| to_address(C++20) | obtains a raw pointer from a pointer-like type (function template) [edit] |
| addressof(C++11) | obtains actual address of an object, even if the & operator is overloaded (function template) [edit] |
| align(C++11) | aligns a pointer in a buffer (function) [edit] |
| assume_aligned(C++20) | informs the compiler that a pointer is aligned (function template) [edit] |
| is_sufficiently_aligned(C++26) | checks whether the pointer points to an object whose alignment has at least the given value (function template) [edit] |
[edit] Low level memory management
Includes e.g. operator new, operator delete, std::set_new_handler.
[edit] C-style memory management
Includes e.g. std::malloc, std::free.
[edit] Uninitialized storage (until C++20)
Several utilities are provided to create and access raw storage.
[edit] Garbage collector support (until C++23)
| Defined in header | |
|---|---|
| declare_reachable(C++11)(removed in C++23) | declares that an object can not be recycled (function) [edit] |
| undeclare_reachable(C++11)(removed in C++23) | declares that an object can be recycled (function template) [edit] |
| declare_no_pointers(C++11)(removed in C++23) | declares that a memory area does not contain traceable pointers (function) [edit] |
| undeclare_no_pointers(C++11)(removed in C++23) | cancels the effect of std::declare_no_pointers (function) [edit] |
| pointer_safety(C++11)(removed in C++23) | lists pointer safety models (enum) [edit] |
| get_pointer_safety(C++11)(removed in C++23) | returns the current pointer safety model (function) [edit] |