[#BloombergLP-bslalg-ContainerBase_EmptyBase]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslalg.adoc[bslalg]::ContainerBase_EmptyBase
:relfileprefix: ../../
:mrdocs:

One of two possible base classes for `ContainerBase`. This class is for stateless allocators (i.e., that have size 0), including `std::allocator` (but not `bsl::allocator`). Provides access to the allocator.

== Synopsis

Declared in `<bslalg_containerbase.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class ALLOCATOR>
class ContainerBase_EmptyBase;
----

== Description

This class does *not* have a subobject of type `ALLOCATOR`. Instead, a (zero‐sized) `ALLOCATOR` is implicitly sited at the address of the start of an object of this class. This approach was chosen in preference to inheriting from `ALLOCATOR` so as to avoid inheriting the interface for `ALLOCATOR` and thus making this class (and all classes derived from it) improperly categorized as an allocator when using the `bslma::IsStdAllocator` metafunction. `ContainerBase_EmptyBase` is an empty class and will not increase the footprint of a derived class.

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslalg/ContainerBase_EmptyBase/AllocatorType.adoc[`AllocatorType`] 
| Alias for the (template parameter) `ALLOCATOR` type.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslalg/ContainerBase_EmptyBase/2constructor.adoc[`ContainerBase_EmptyBase`]         [.small]#[constructor]#
| Construct this object to hold a copy of the specified `basicAllocator` of the parameterized `ALLOCATOR` type.
| xref:BloombergLP/bslalg/ContainerBase_EmptyBase/2destructor.adoc[`~ContainerBase_EmptyBase`] [.small]#[destructor]#
| Destroy this object.
| xref:BloombergLP/bslalg/ContainerBase_EmptyBase/allocatorRef-0b.adoc[`allocatorRef`] 
| `allocatorRef` overloads
|===



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