[#bsl-unordered_map-02b-try_emplace-050]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_map-02b.adoc[unordered_map]::try_emplace
:relfileprefix: ../../
:mrdocs:

`try_emplace` overloads

== Synopses

Declared in `<bslstl_unorderedmap.h>`

Emplace a value for movable `key` if missing.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/pair-0b.adoc[pair<iterator, bool>]
xref:bsl/unordered_map-02b/try_emplace-09b.adoc[try_emplace](
    xref:BloombergLP/bslmf/MovableRef.adoc[BloombergLP::bslmf::MovableRef<KEY>] key,
    Args&&... args);
----

[.small]#xref:bsl/unordered_map-02b/try_emplace-09b.adoc[_» more..._]#

Emplace a value for `key` if no equivalent key already exists.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/pair-0b.adoc[pair<iterator, bool>]
xref:bsl/unordered_map-02b/try_emplace-02.adoc[try_emplace](
    KEY const& key,
    Args&&... args);
----

[.small]#xref:bsl/unordered_map-02b/try_emplace-02.adoc[_» more..._]#

Emplace a value for transparent `key` if missing.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class LOOKUP_KEY,
    class... Args>
xref:bsl/pair-0b.adoc[pair<iterator, bool>]
xref:bsl/unordered_map-02b/try_emplace-07.adoc[try_emplace](
    LOOKUP_KEY&& key,
    Args&&... args)
requires BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value
        && !bsl::is_convertible<LOOKUP_KEY&&, const_iterator>::value
        && !bsl::is_convertible<LOOKUP_KEY&&, iterator>::value;
----

[.small]#xref:bsl/unordered_map-02b/try_emplace-07.adoc[_» more..._]#

Emplace a value for movable `key` at `hint` if missing.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/unordered_map-02b/iterator.adoc[iterator]
xref:bsl/unordered_map-02b/try_emplace-09d.adoc[try_emplace](
    xref:bsl/unordered_map-02b/const_iterator.adoc[const_iterator] hint,
    xref:BloombergLP/bslmf/MovableRef.adoc[BloombergLP::bslmf::MovableRef<KEY>] key,
    Args&&... args);
----

[.small]#xref:bsl/unordered_map-02b/try_emplace-09d.adoc[_» more..._]#

Emplace a value for `key` at `hint` if missing.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/unordered_map-02b/iterator.adoc[iterator]
xref:bsl/unordered_map-02b/try_emplace-05e.adoc[try_emplace](
    xref:bsl/unordered_map-02b/const_iterator.adoc[const_iterator] hint,
    KEY const& key,
    Args&&... args);
----

[.small]#xref:bsl/unordered_map-02b/try_emplace-05e.adoc[_» more..._]#

Emplace with transparent lookup key at `hint`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class LOOKUP_KEY,
    class... Args>
xref:bsl/unordered_map-02b/iterator.adoc[iterator]
xref:bsl/unordered_map-02b/try_emplace-0f.adoc[try_emplace](
    xref:bsl/unordered_map-02b/const_iterator.adoc[const_iterator] hint,
    LOOKUP_KEY&& key,
    Args&&... args)
requires BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value;
----

[.small]#xref:bsl/unordered_map-02b/try_emplace-0f.adoc[_» more..._]#

== Return Value

* iterator to the element and whether insertion occurred
* iterator to the existing or newly inserted element

== Parameters

[cols="1,4"]
|===
| Name| Description
| *key*
| key to look up
| *args*
| constructor arguments for the new element
| *hint*
| iterator hint for insertion
|===


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