[#BloombergLP-bdlar-NullableValueConstRef]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlar.adoc[bdlar]::NullableValueConstRef
:relfileprefix: ../../
:mrdocs:

Type‐erased const reference to an object in the `bdlat` nullable‐value type category.

== Synopsis

Declared in `<bdlar_nullablevalueref.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class NullableValueConstRef;
----

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlar/NullableValueConstRef/CategoryTag.adoc[`CategoryTag`] 
| Tag type indicating the nullable‐value type category.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlar/NullableValueConstRef/2constructor-048.adoc[`NullableValueConstRef`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bdlar/NullableValueConstRef/accessValue.adoc[`accessValue`] 
| Invoke the specified `accessor` on the referred non‐null value. The supplied `accessor` must be a callable type that can be called as if it had the following signature: ` int accessor(const VALUE& refOrValue); ` Return the value from the invocation of `accessor`. The behavior is undefined if the referred object is null.
| xref:BloombergLP/bdlar/NullableValueConstRef/isNull.adoc[`isNull`] 
| Return `true` if the referred object contains a null value, and `false` otherwise.
| xref:BloombergLP/bdlar/NullableValueConstRef/objectAddress.adoc[`objectAddress`] 
| Return a pointer to the wrapped object.
| xref:BloombergLP/bdlar/NullableValueConstRef/valueCategory.adoc[`valueCategory`] 
| Return the value type category.
| xref:BloombergLP/bdlar/NullableValueConstRef/vtable.adoc[`vtable`] 
| Return a pointer to the vtable.
| xref:BloombergLP/bdlar/NullableValueConstRef/xsdName.adoc[`xsdName`] 
| Return the `bdlat_TypeName::xsdName` value for the underlying object.
|===


== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlar/bdlat_TypeName_xsdName-06.adoc[`bdlat_TypeName_xsdName`]
| Return the `bdlat_TypeName::xsdName` value for the specified `ref`.
| xref:BloombergLP/bdlar/bdlat_nullableValueAccessValue-09.adoc[`bdlat_nullableValueAccessValue`]
| Invoke `accessor` on the non‐null value held by `ref`.
| xref:BloombergLP/bdlar/bdlat_nullableValueIsNull-0a.adoc[`bdlat_nullableValueIsNull`]
| Return `true` if the specified `ref` contains a null value, and `false` otherwise.
|===


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