[#bsl-unordered_map-02b-contains-0c]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_map-02b.adoc[unordered_map]::contains
:relfileprefix: ../../
:mrdocs:

Return whether this unordered map contains an equivalent `key`.

== Synopsis

Declared in `<bslstl_unorderedmap.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class LOOKUP_KEY>
bool
contains(LOOKUP_KEY const& key) const
requires BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value &&
            BloombergLP::bslmf::IsTransparentPredicate<EQUAL,
                                                       LOOKUP_KEY>::value;
----

== Description

Return `true` if this unordered map contains an element whose key is equivalent to the specified `key`.

Note: implemented inline due to Sun CC compilation error

== Return Value

`true` if present, otherwise `false`

== Parameters

[cols="1,4"]
|===
| Name| Description
| *key*
| key to look up
|===


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