[#BloombergLP-bdlb-NullableAllocatedValue-isNull] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::xref:BloombergLP/bdlb/NullableAllocatedValue.adoc[NullableAllocatedValue]::isNull :relfileprefix: ../../../ :mrdocs: Return `false` if this object contains a value, and `true` otherwise. Note that this is the opposite of `has_value`. == Synopsis Declared in `<bdlb_nullableallocatedvalue.h>` [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- bool isNull() const noexcept; ---- [.small]#Created with https://www.mrdocs.com[MrDocs]#