[#bsl-unordered_map-0bf-at-08]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_map-0bf.adoc[unordered&lowbar;map&lt;basic&lowbar;string&lt;char&gt;, Json, TransparentHash, TransparentEqualTo&gt;]::at
:relfileprefix: ../../
:mrdocs:

Return a reference providing non&hyphen;modifiable access to the mapped&hyphen;value associated with the specified `key`, if such an entry exists&semi; otherwise throw a `std&colon;&colon;out&lowbar;of&lowbar;range` exception&period; Note that this method is not exception&hyphen;neutral&period;

== Synopsis

Declared in `&lt;bslstl&lowbar;unorderedmap&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/add_lvalue_reference-02/type.adoc[add&lowbar;lvalue&lowbar;reference&lt;Json const&gt;::type]
at(xref:bsl/unordered_map-0bf/key_type.adoc[key&lowbar;type] const& key) const;
----


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