std::scoped_allocator_adaptor

 

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std::scoped_allocator_adaptor

Member functions

scoped_allocator_adaptor::scoped_allocator_adaptor

scoped_allocator_adaptor::~scoped_allocator_adaptor

scoped_allocator_adaptor::inner_allocator

scoped_allocator_adaptor::outer_allocator

scoped_allocator_adaptor::allocate

scoped_allocator_adaptor::deallocate

scoped_allocator_adaptor::max_size

scoped_allocator_adaptor::construct

scoped_allocator_adaptor::destroy

scoped_allocator_adaptor::select_on_container_copy_construction

Non-member functions

operator== operator!=

 

Defined in header <scoped_allocator>
template< class OuterAlloc, class... InnerAlloc > class scoped_allocator_adaptor : public OuterAlloc;		(since C++11)

The std::scoped_allocator_adaptor class template is an allocator which can be used with multilevel containers (vector of sets of lists of tuples of maps, etc). It is instantiated with one outer allocator type OuterAlloc and zero or more inner allocator types InnerAlloc.... A container constructed directly with a scoped_allocator_adaptor uses OuterAlloc to allocate its elements, but if an element is itself a container, it uses the first inner allocator. The elements of that container, if they are themselves containers, use the second inner allocator, etc. If there are more levels to the container than there are inner allocators, the last inner allocator is reused for all further nested containers.

For the purpose of scoped_allocator_adaptor, if the next inner allocator is A, any class T for which std::uses_allocator<T,A>::value == true participates in the recursion as if it was a container. Additionally, std::pair is treated as such a container by specific overloads of scoped_allocator_adaptor::construct.

Typical implementation holds an instance of a std::scoped_allocator_adaptor<InnerAllocs...> as a member object.

Member types

Type	Definition
outer_allocator_type	OuterAlloc
inner_allocator_type	scoped_allocator_adaptor<InnerAllocs...> or, if sizeof...(InnerAllocs) == 0, scoped_allocator_adaptor<OuterAlloc>
value_type	std::allocator_traits<OuterAlloc>::value_type
size_type	std::allocator_traits<OuterAlloc>::size_type
difference_type	std::allocator_traits<OuterAlloc>::difference_type
pointer	std::allocator_traits<OuterAlloc>::pointer
const_pointer	std::allocator_traits<OuterAlloc>::const_pointer
void_pointer	std::allocator_traits<OuterAlloc>::void_pointer
const_void_pointer	std::allocator_traits<OuterAlloc>::const_void_pointer
propagate_on_container_copy_assignment std::true_type if std::allocator_traits<A>::propagate_on_container_copy_assignment::value is true for at least one allocator A among OuterAlloc and InnerAlloc...
propagate_on_container_move_assignment std::true_type if std::allocator_traits<A>::propagate_on_container_move_assignment::value is true for at least one allocator A among OuterAlloc and InnerAlloc...
propagate_on_container_swap std::true_type if std::allocator_traits<A>::propagate_on_container_swap::value is true for at least one allocator A among OuterAlloc and InnerAlloc...
rebind template< class T > struct rebind { typedef scoped_allocator_adaptor< std::allocator_traits<OuterAlloc>::template rebind_alloc<T>, InnerAllocs... > other; };

Member functions

(constructor)	creates a new scoped_allocator_adaptor instance (public member function)
(destructor)	destructs a scoped_allocator_adaptor instance (public member function)
inner_allocator	obtains an inner_allocator reference (public member function)
outer_allocator	obtains an outer_allocator reference (public member function)
allocate	allocates uninitialized storage using the outer allocator (public member function)
deallocate	allocates storage using the outer allocator (public member function)
max_size	returns the largest allocation size supported by the outer allocator (public member function)
construct	constructs an object in allocated storage, passing the inner allocator to its constructor if appropriate (public member function)
destroy	desrtucts an object in allocated storage (public member function)
select_on_container_copy_construction	copies the state of scoped_allocator_adaptor and all its allocators (public member function)

Non-member functions

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

See also

allocator_traits (C++11)	provides information about allocator types (class template)
uses_allocator (C++11)	checks if the specified type supports uses-allocator construction (class template)
allocator	the default allocator (class template)