[#BloombergLP-bdlar-NullableValueConstRef-isNull] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlar.adoc[bdlar]::xref:BloombergLP/bdlar/NullableValueConstRef.adoc[NullableValueConstRef]::isNull :relfileprefix: ../../../ :mrdocs: Return `true` if the referred object contains a null value, and `false` otherwise. == Synopsis Declared in `<bdlar_nullablevalueref.h>` [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- bool isNull() const; ---- [.small]#Created with https://www.mrdocs.com[MrDocs]#