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... | |
is_always_equal (C++17) std::true_type if std::allocator_traits<A>::is_always_equal::value is true for every 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
creates a new scoped_allocator_adaptor instance (public member function) | |
(destructor)
| destructs a scoped_allocator_adaptor instance (public member function) |
operator=
| assigns a scoped_allocator_adaptor (public member function) |
obtains an inner_allocator reference (public member function) | |
obtains an outer_allocator reference (public member function) | |
allocates uninitialized storage using the outer allocator (public member function) | |
deallocates storage using the outer allocator (public member function) | |
returns the largest allocation size supported by the outer allocator (public member function) | |
constructs an object in allocated storage, passing the inner allocator to its constructor if appropriate (public member function) | |
destructs an object in allocated storage (public member function) | |
copies the state of scoped_allocator_adaptor and all its allocators (public member function) |
Non-member functions
compares two scoped_allocator_adaptor instances (public member function) |
See also
(C++11) | provides information about allocator types (class template) |
(C++11) | checks if the specified type supports uses-allocator construction (class template) |
the default allocator (class template) |
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