Dynamic memory management

Smart pointers

Smart pointers enable automatic, exception-safe, object lifetime management.

Defined in header <memory>
Pointer categories
unique_ptr (C++11)	smart pointer with unique object ownership semantics (class template)
shared_ptr (C++11)	smart pointer with shared object ownership semantics (class template)
weak_ptr (C++11)	weak reference to an object managed by std::shared_ptr (class template)
auto_ptr (removed in C++17)	smart pointer with strict object ownership semantics (class template)
Helper classes
owner_less (C++11)	provides mixed-type owner-based ordering of shared and weak pointers (class template)
enable_shared_from_this (C++11)	allows an object to create a shared_ptr referring to itself (class template)
bad_weak_ptr (C++11)	exception thrown when accessing a weak_ptr which refers to already destroyed object (class)
default_delete (C++11)	default deleter for unique_ptr (class template)

Allocators

Allocators are class templates encapsulating memory allocation strategy. This allows generic containers to decouple memory management from the data itself.

Defined in header <memory>
allocator	the default allocator (class template)
allocator_traits (C++11)	provides information about allocator types (class template)
allocator_arg_t (C++11)	tag type used to select allocator-aware constructor overloads (class)
allocator_arg (C++11)	an object of type std::allocator_arg_t used to select allocator-aware constructors (constant)
uses_allocator (C++11)	checks if the specified type supports uses-allocator construction (class template)
uses_allocator_construction_args (C++20)	prepares the argument list matching the flavor of uses-allocator construction required by the given type (function template)
make_obj_using_allocator (C++20)	creates an object of the given type by means of uses-allocator construction (function template)
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)
Defined in header <scoped_allocator>
scoped_allocator_adaptor (C++11)	implements multi-level allocator for multi-level containers (class template)
Defined in header <memory_resource>
Defined in namespace pmr
polymorphic_allocator (C++17)	an allocator that supports run-time polymorphism based on the std::memory_resource it is constructed with (class template)

Memory resources

Memory resources implement memory allocation strategies that can be used by std::pmr::polymorphic_allocator.

Defined in header <memory_resource>
Defined in namespace pmr
memory_resource (C++17)	an abstract interface for classes that encapsulate memory resources (class)
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)
null_memory_resource (C++17)	returns a static std::pmr::memory_resource that performs no allocation (function)
get_default_resource (C++17)	gets the default std::pmr::memory_resource (function)
set_default_resource (C++17)	sets the default std::pmr::memory_resource (function)
pool_options (C++17)	a set of constructor options for pool resources (class)
synchronized_pool_resource (C++17)	a thread-safe std::pmr::memory_resource for managing allocations in pools of different block sizes (class)
unsynchronized_pool_resource (C++17)	a thread-unsafe std::pmr::memory_resource for managing allocations in pools of different block sizes (class)
monotonic_buffer_resource (C++17)	a special-purpose std::pmr::memory_resource that releases the allocated memory only when the resource is destroyed (class)

Uninitialized storage

Several utilities are provided to create and access raw storage.

Defined in header <memory>
uninitialized_copy	copies a range of objects to an uninitialized area of memory (function template)
uninitialized_copy_n (C++11)	copies a number of objects to an uninitialized area of memory (function template)
uninitialized_fill	copies an object to an uninitialized area of memory, defined by a range (function template)
uninitialized_fill_n	copies an object to an uninitialized area of memory, defined by a start and a count (function template)
uninitialized_move (C++17)	moves a range of objects to an uninitialized area of memory (function template)
uninitialized_move_n (C++17)	moves a number of objects to an uninitialized area of memory (function template)
uninitialized_default_construct (C++17)	constructs objects by default-initialization in an uninitialized area of memory, defined by a range (function template)
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)
uninitialized_value_construct (C++17)	constructs objects by value-initialization in an uninitialized area of memory, defined by a range (function template)
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)
destroy_at (C++17)	destroys an object at a given address (function template)
destroy (C++17)	destroys a range of objects (function template)
destroy_n (C++17)	destroys a number of objects in a range (function template)
raw_storage_iterator (deprecated in C++17)(removed in C++20)	an iterator that allows standard algorithms to store results in uninitialized memory (class template)
get_temporary_buffer (deprecated in C++17)(removed in C++20)	obtains uninitialized storage (function template)
return_temporary_buffer (deprecated in C++17)(removed in C++20)	frees uninitialized storage (function template)

Constrained uninitialized memory algorithms (C++20)

C++20 provides constrained uninitialized memory algorithms that accept range arguments or iterator-sentinel pairs.

Defined in header <memory>
Defined in namespace std::ranges
uninitialized_copy (C++20)	copies a range of objects to an uninitialized area of memory (niebloid)
uninitialized_copy_n (C++20)	copies a number of objects to an uninitialized area of memory (niebloid)
uninitialized_fill (C++20)	copies an object to an uninitialized area of memory, defined by a range (niebloid)
uninitialized_fill_n (C++20)	copies an object to an uninitialized area of memory, defined by a start and a count (niebloid)
uninitialized_move (C++20)	moves a range of objects to an uninitialized area of memory (niebloid)
uninitialized_move_n (C++20)	moves a number of objects to an uninitialized area of memory (niebloid)
uninitialized_default_construct (C++20)	constructs objects by default-initialization in an uninitialized area of memory, defined by a range (niebloid)
uninitialized_default_construct_n (C++20)	constructs objects by default-initialization in an uninitialized area of memory, defined by a start and count (niebloid)
uninitialized_value_construct (C++20)	constructs objects by value-initialization in an uninitialized area of memory, defined by a range (niebloid)
uninitialized_value_construct_n (C++20)	constructs objects by value-initialization in an uninitialized area of memory, defined by a start and a count (niebloid)
destroy_at (C++20)	destroys an object at a given address (niebloid)
destroy (C++20)	destroys a range of objects (niebloid)
destroy_n (C++20)	destroys a number of objects in a range (niebloid)

Garbage collector support

Defined in header <memory>
declare_reachable (C++11)	declares that an object can not be recycled (function)
undeclare_reachable (C++11)	declares that an object can be recycled (function template)
declare_no_pointers (C++11)	declares that a memory area does not contain traceable pointers (function)
undeclare_no_pointers (C++11)	cancels the effect of std::declare_no_pointers (function)
pointer_safety (C++11)	lists pointer safety models (enum)
get_pointer_safety (C++11)	returns the current pointer safety model (function)

Miscellaneous

Defined in header <memory>
pointer_traits (C++11)	provides information about pointer-like types (class template)
to_address (C++20)	obtains a raw pointer from a pointer-like type (function template)
addressof (C++11)	obtains actual address of an object, even if the & operator is overloaded (function template)
align (C++11)	aligns a pointer in a buffer (function)
assume_aligned (C++20)	informs the compiler that a pointer is aligned (function template)

C-style memory management

Includes e.g. std::malloc, std::free.

Low level memory management

Includes e.g. operator new , operator delete , std::set_new_handler.