[#BloombergLP-bslma-HasAllocatorType-00]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslma.adoc[bslma]::HasAllocatorType
:relfileprefix: ../../
:mrdocs:

Metafunction that yields whether `TYPE` has a nested C++11 `allocator_type`.

== Synopsis

Declared in `<bslma_hasallocatortype.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class TYPE,
    class = void>
struct HasAllocatorType
    : xref:bsl/false_type.adoc[bsl::false_type]
----

== Description

This metafunction yields `bsl::true_type` if the specified template‐parameter `TYPE` has a nested type named `allocator_type` that meets the requirements for a C++11 allocator, and `bsl::false_type` otherwise. This primary template, yielding `false_type`, is instantiated for types for which `allocator_type` does not exist or is not an allocator type. Note that instantiation will fail if `allocator_type` exists but is not public within `TYPE` or if any of the required members of `TYPE::allocator_type` exist but are not public (though only `value_type` and `allocate` are tested at present).

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:bsl/false_type.adoc[bsl::false_type]`
| Metafunction representing the boolean constant `false`.
|===

== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/HasAllocatorType-0f.adoc[`HasAllocatorType<TYPE, bsl::void_t<TYPE::allocator_type>>`] 
| Partial specialization of `HasAllocatorType` for types with a C++11 `allocator_type`.
|===



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