std::allocator

 

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Dynamic memory management

Low level memory management
Allocators
allocator
allocator_traits (C++11)
allocator_arg_t (C++11)
allocator_arg (C++11)
uses_allocator (C++11)
scoped_allocator_adaptor (C++11)
Uninitialized storage
uninitialized_copy
uninitialized_copy_n (C++11)
uninitialized_fill
uninitialized_fill_n
raw_storage_iterator
get_temporary_buffer
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unique_ptr (C++11)
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owner_less (C++11)
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bad_weak_ptr (C++11)
default_delete (C++11)
Garbage collection support
declare_reachable (C++11)
undeclare_reachable (C++11)
declare_no_pointers (C++11)
undeclare_no_pointers (C++11)
pointer_safety (C++11)
get_pointer_safety (C++11)
Miscellaneous
pointer_traits (C++11)
addressof (C++11)
align (C++11)
C Library
malloc calloc	realloc free

 

std::allocator

Member functions

allocator::allocator

allocator::~allocator

allocator::address

allocator::allocate

allocator::deallocate

allocator::max_size

allocator::construct

allocator::destroy

Non-member functions

operator== operator!=

 

Defined in header <memory>
template< class T > struct allocator;	(1)
template<> struct allocator<void>;	(2)

1) The std::allocator class template is the default allocator used by all standard library containers if no user-specified allocator is provided. Custom allocators are required to implement the public interface of std::allocator or to provide a specialization of std::allocator_traits.

2) Specialization for void is provided, which lacks the member typedefs reference and const_reference because there are no references to void and size_type and difference_type because there are no arrays of void. This specialization declares no member functions.

Notes

The default allocator and all custom allocators are required to be stateless: all instances of a given allocator type have to be interchangeable, compare equal, and deallocate memory allocated by any other instance of the same allocator type. (until C++11)

The default allocator is stateless, all instances compare equal and are able to deallocate memory allocated by any other instance, but custom allocators may hold state. Each container or another allocator-aware object stores an instance of the supplied allocator and controls allocator replacement through std::allocator_traits. (since C++11)

Member types

Type	Definition
value_type	T
pointer	T*
const_pointer	const T*
reference	T&
const_reference	const T&
size_type	std::size_t
difference_type	std::ptrdiff_t
rebind	template< class U > struct rebind { typedef allocator<U> other; };

Member functions

(constructor)	creates a new allocator instance (public member function)
(destructor)	destructs an allocator instance (public member function)
address	obtains the address of an object, even if operator& is overloaded (public member function)
allocate	allocates uninitialized storage (public member function)
deallocate	deallocates storage (public member function)
max_size	returns the largest supported allocation size (public member function)
construct	constructs an object in allocated storage (public member function)
destroy	destructs an object in allocated storage (public member function)

Non-member functions

operator== operator!=	compares two allocator instances (public member function)

See also

allocator_traits (C++11)	provides information about allocator types (class template)
scoped_allocator_adaptor (C++11)	implements multi-level allocator for multi-level containers (class template)
uses_allocator (C++11)	checks if the specified type supports uses-allocator construction (class template)