[#BloombergLP-bslstl-HashTable-09-insertIfMissing-0a]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::xref:BloombergLP/bslstl/HashTable-09.adoc[HashTable<UnorderedMapKeyConfiguration<basic_string<char> const, pair<basic_string<char> const, Json>>, TransparentHash, TransparentEqualTo, allocator<pair<basic_string<char> const, Json>>>]::insertIfMissing
:relfileprefix: ../../../
:mrdocs:

Insert the specified `value` into this hash‐table if a key equivalent to that of `value` does not already exist in this hash‐table. Return the address of the (possibly newly inserted) element in this hash‐table whose key is equivalent to that of `value`. If this hash‐table contains more than one element with a matching key, return the first such element (from the contiguous sequence of elements having a matching key). Additional buckets are allocated, as needed, to preserve the invariant `loadFactor <= maxLoadFactor`. If this function tries to allocate a number of buckets larger than can be represented by this hash‐table's `SizeType`, a `std::length_error` exception is thrown. This method requires that the `ValueType` defined in the (template parameter) type `KEY_CONFIG` be `copy‐insertable` into this hash‐table (see {Requirements on `KEY_CONFIG`});

== Synopsis

Declared in `<bslstl_hashtable.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslalg/BidirectionalLink.adoc[bslalg::BidirectionalLink]*
insertIfMissing(
    bool* isInsertedFlag,
    xref:BloombergLP/bslstl/HashTable-09/ValueType.adoc[ValueType] const& value);
----


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