[#BloombergLP-bdlb-NullOptType]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::NullOptType
:relfileprefix: ../../
:mrdocs:

Tag type representing an empty nullable value.

== Synopsis

Declared in `<bdlb_nullopt.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
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typedef xref:bsl/nullopt_t.adoc[bsl::nullopt_t] NullOptType;
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== Description

This `class` provides an empty tag type so that `bdlb::NullableValue` can be explicitly constructed in or assigned to an empty state. There are no publicly accessible constructors for this type other than the copy constructor. In particular, it is not default constructible, nor list‐initializable in C++11.


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