[#BloombergLP-bslma-AllocatorTraits_IsAlwaysEqual-0a]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslma.adoc[bslma]::xref:BloombergLP/bslma/AllocatorTraits_IsAlwaysEqual-0e.adoc[AllocatorTraits&lowbar;IsAlwaysEqual]&lt;ALLOC, false&gt;
:relfileprefix: ../../
:mrdocs:

Sets `is&lowbar;always&lowbar;equal` to `bsl&colon;&colon;is&lowbar;empty&lt;ALLOC&gt;` when not defined by `ALLOC`&period;

== Synopsis

Declared in `&lt;bslma&lowbar;allocatortraits&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template&lt;class ALLOC&gt;
struct xref:BloombergLP/bslma/AllocatorTraits_IsAlwaysEqual-0e.adoc[AllocatorTraits&lowbar;IsAlwaysEqual]&lt;ALLOC, false&gt;
    : xref:bsl/is_empty.adoc[bsl::is&lowbar;empty&lt;ALLOC&gt;]
----

== Description

This `struct` template sets the boolean type for the attribute named `is&lowbar;always&lowbar;equal` to `bsl&colon;&colon;is&lowbar;empty&lt;ALLOC&gt;` if the given (template parameter) `ALLOC` does not define such an alias (i&period;e&period;, if `false &equals;&equals; AllocatorTraits&lowbar;HasIsAlwaysEqual&lt;ALLOCATOR&lowbar;TYPE&gt;&colon;&colon;value`)&period;

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:bsl/is_empty.adoc[bsl::is&lowbar;empty&lt;ALLOC&gt;]`
| Meta&hyphen;function for detecting empty class types&period;
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:bsl/integral_constant-02/type.adoc[`type`] 
| Alias for this `integral&lowbar;constant` specialization&period;
| xref:bsl/integral_constant-02/value_type.adoc[`value&lowbar;type`] 
| Alias for the (template parameter) `t&lowbar;TYPE`&period;
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/integral_constant-02/operator_call.adoc[`operator()`] 
| Return a copy of the template argument `t&lowbar;VALUE`&period;
| xref:bsl/integral_constant-02/2conversion.adoc[`operator t&lowbar;TYPE`] 
| Return a copy of the template argument `t&lowbar;VALUE`&period;
|===


== Static Data Members

[cols="1,4"]
|===
| Name| Description
| xref:bsl/integral_constant-02/value.adoc[`value`] 
| The compile&hyphen;time constant value of this metafunction&period;
|===



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