[#BloombergLP-bdlat_NullableValueFunctions-IsNullableValue-030]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlat_NullableValueFunctions.adoc[bdlat&lowbar;NullableValueFunctions]::IsNullableValue
:relfileprefix: ../../
:mrdocs:

This `struct` should be specialized for third&hyphen;party types that need to expose &quot;nullable&quot; behavior&period; See the component&hyphen;level documentation for further information&period;

== Synopsis

Declared in `&lt;bdlat&lowbar;nullablevaluefunctions&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template&lt;class TYPE&gt;
struct IsNullableValue
    : xref:bsl/false_type.adoc[bsl::false&lowbar;type]
----

== Base Classes

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

== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlat_NullableValueFunctions/IsNullableValue-03b.adoc[`IsNullableValue&lt;bdlar::NullableValueConstRef&gt;`] 
| Trait indicating that `bdlar&colon;&colon;NullableValueConstRef` is a `bdlat` nullable&hyphen;value type&period;
| xref:BloombergLP/bdlat_NullableValueFunctions/IsNullableValue-0d4.adoc[`IsNullableValue&lt;bdlar::NullableValueRef&gt;`] 
| Trait indicating that `bdlar&colon;&colon;NullableValueRef` is a `bdlat` nullable&hyphen;value type&period;
| xref:BloombergLP/bdlat_NullableValueFunctions/IsNullableValue-0e.adoc[`IsNullableValue&lt;bdlb::NullableAllocatedValue&lt;TYPE&gt;&gt;`] 
| Specialization of `IsNullableValue` for `bdlb&colon;&colon;NullableAllocatedValue`&period;
| xref:BloombergLP/bdlat_NullableValueFunctions/IsNullableValue-0d2.adoc[`IsNullableValue&lt;bdlb::NullableValue&lt;TYPE&gt;&gt;`] 
| Specialization of `IsNullableValue` for `bdlb&colon;&colon;NullableValue`&period;
|===


== Derived Classes

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlar/IsNullable.adoc[`IsNullable`] 
| Meta&hyphen;function indicating whether the specified `t&lowbar;TYPE` is a nullable value type&period;
|===


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