[#BloombergLP-bslmt-Once-OnceLock]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslmt.adoc[bslmt]::xref:BloombergLP/bslmt/Once.adoc[Once]::OnceLock
:relfileprefix: ../../../
:mrdocs:

Special token created by a single thread to pass to the `enter`, `leave`, and `cancel` methods&period;

== Synopsis

Declared in `&lt;bslmt&lowbar;once&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
typedef xref:BloombergLP/bslmt/QLockGuard.adoc[QLockGuard] OnceLock;
----


[.small]#Created with https://www.mrdocs.com[MrDocs]#
