[#bsl-unordered_map-0bf-try_emplace-092]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_map-0bf.adoc[unordered_map<basic_string<char>, Json, TransparentHash, TransparentEqualTo>]::try_emplace
:relfileprefix: ../../
:mrdocs:

`try_emplace` overloads

== Synopses

Declared in `<bslstl_unorderedmap.h>`

If a key equivalent to the specified `key` already exists in this unordered_map, return a pair containing an iterator referring to the existing item and `false`. Otherwise, insert into this map a newly‐created `value_type` object, constructed from `std::forward<KEY>(key)` and the specified `args`, and return a pair containing an iterator referring to the newly‐created entry, and `true`. This method requires that the (template parameter) types `KEY` and `VALUE` are `emplace‐constructible` from `key` and `args` respectively. For C++03, `VALUE` must also be `copy‐constructible`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/pair-0b.adoc[pair<iterator, bool>]
xref:bsl/unordered_map-0bf/try_emplace-06.adoc[try_emplace](
    xref:BloombergLP/bslmf/MovableRef.adoc[BloombergLP::bslmf::MovableRef<basic_string<char>>] key,
    Args&&... args);
----

[.small]#xref:bsl/unordered_map-0bf/try_emplace-06.adoc[_» more..._]#

If a key equivalent to the specified `key` already exists in this unordered_map, return a pair containing an iterator referring to the existing item, and `false`. Otherwise, insert into this map a newly‐created `value_type` object, constructed from `key` and the specified `args`, and return a pair containing an iterator referring to the newly‐created entry and `true`. This method requires that the (template parameter) types `KEY` and `VALUE` are `emplace‐constructible` from `key` and `args` respectively. For C++03, `VALUE` must also be `copy‐constructible`.


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

[.small]#xref:bsl/unordered_map-0bf/try_emplace-0c.adoc[_» more..._]#

If a key equivalent to the specified `key` already exists in this unordered_map, return a pair containing an iterator referring to the existing item and `false`. Otherwise, insert into this map a newly‐created `value_type` object, constructed from `std::forward<LOOKUP_KEY>(key)` and the specified `args`, and return a pair containing an iterator referring to the newly‐created entry, and `true`. This method requires that the (template parameter) types `KEY` and `VALUE` are `emplace‐constructible` from `key` and `args` respectively. For C++03, `VALUE` must also be `copy‐constructible`.


[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-0bf/try_emplace-09b.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-0bf/try_emplace-09b.adoc[_» more..._]#

If a key equivalent to the specified `key` already exists in this unordered_map, return an iterator referring to the existing item. Otherwise, insert into this map a newly‐created `value_type` object, constructed from `std::forward<KEY>(key)` and the specified `args`, and return an iterator referring to the newly‐created entry. Use the specified `hint` as a starting point for checking to see if the key already in the unordered_map. This method requires that the (template parameter) types `KEY` and `VALUE` are `emplace‐constructible` from `key` and `args` respectively. For C++03, `VALUE` must also be `copy‐constructible`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/unordered_map-0bf/iterator.adoc[iterator]
xref:bsl/unordered_map-0bf/try_emplace-0b.adoc[try_emplace](
    xref:bsl/unordered_map-0bf/const_iterator.adoc[const_iterator] hint,
    xref:BloombergLP/bslmf/MovableRef.adoc[BloombergLP::bslmf::MovableRef<basic_string<char>>] key,
    Args&&... args);
----

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

If a key equivalent to the specified `key` already exists in this unordered_map, return an iterator referring to the existing item. Otherwise, insert into this map a newly‐created `value_type` object, constructed from `key` and the specified `args`, and return an iterator referring to the newly‐created entry. Use the specified `hint` as a starting point for checking to see if the key already in the unordered_map. This method requires that the (template parameter) types `KEY` and `VALUE` are `emplace‐constructible` from `key` and `args` respectively. For C++03, `VALUE` must also be `copy‐constructible`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class... Args>
xref:bsl/unordered_map-0bf/iterator.adoc[iterator]
xref:bsl/unordered_map-0bf/try_emplace-0f.adoc[try_emplace](
    xref:bsl/unordered_map-0bf/const_iterator.adoc[const_iterator] hint,
    xref:bsl/basic_string-0faf.adoc[basic_string<char>] const& key,
    Args&&... args);
----

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

If a key equivalent to the specified `key` already exists in this unordered_map, return an iterator referring to the existing item. Otherwise, insert into this map a newly‐created `value_type` object, constructed from `std::forward<LOOKUP_KEY>(key)` and the specified `args`, and return an iterator referring to the newly‐created entry. Use the specified `hint` as a starting point for checking to see if the key already in the unordered_map. This method requires that the (template parameter) types `KEY` and `VALUE` are `emplace‐constructible` from `key` and `args` respectively. For C++03, `VALUE` must also be `copy‐constructible`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class LOOKUP_KEY,
    class... Args>
xref:bsl/unordered_map-0bf/iterator.adoc[iterator]
xref:bsl/unordered_map-0bf/try_emplace-02.adoc[try_emplace](
    xref:bsl/unordered_map-0bf/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-0bf/try_emplace-02.adoc[_» more..._]#


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