[#BloombergLP-bslstl-Variant_AllocatorBase-0e]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::Variant_AllocatorBase
:relfileprefix: ../../
:mrdocs:

This component‐private struct keeps track of the allocator for a `bsl::variant` object. The primary template is used when the `variant` is not allocator‐aware (because it has no allocator‐aware alternatives).

== Synopsis

Declared in `<bslstl_variant.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<bool t_AA>
struct Variant_AllocatorBase;
----

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Variant_AllocatorBase-0e/mechanism.adoc[`mechanism`] 
| Return a null pointer. Note that this method has the same return type as the allocator‐aware version so that the remainder of the implementation of `bsl::variant` is abstracted with respect to whether or not the specialization is allocator‐aware; this is why both methods return `bslma::Allocator*` instead of `bsl::allocator<char>`. The returned pointer will be ignored (and not dereferenced) when passed to `bslma::ConstructionUtil::construct`.
|===


== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Variant_AllocatorBase-04.adoc[`Variant_AllocatorBase<true>`] 
| This specialization is used when the `variant` is allocator‐aware.
|===


== Derived Classes

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Variant_Base.adoc[`Variant_Base`] 
| This component‐private struct defines the data representation of `bsl::variant` and contains the implementations of its special member functions (which must be defaulted in `bsl::variant` itself). This class also contains implementations of additional constructors and methods needed for the correct functionality of the `variant` class hierarchy.
|===


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