[#BloombergLP-bdld-Datum-createUninitializedMap-0e8]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdld.adoc[bdld]::xref:BloombergLP/bdld/Datum.adoc[Datum]::createUninitializedMap
:relfileprefix: ../../../
:mrdocs:

Create an uninitialized key‐owning datum map and load it into `result`.

== Synopsis

Declared in `<bdld_datum.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
void
createUninitializedMap(
    xref:BloombergLP/bdld/DatumMutableMapOwningKeysRef.adoc[DatumMutableMapOwningKeysRef]* result,
    xref:BloombergLP/bdld/Datum/SizeType.adoc[SizeType] capacity,
    xref:BloombergLP/bdld/Datum/SizeType.adoc[SizeType] keysCapacity,
    xref:BloombergLP/bdld/Datum/AllocatorType.adoc[AllocatorType] const& allocator);
----

== Description

Load the specified `result` with a reference to a newly created datum‐key‐owning map having the specified `capacity` and `keysCapacity`, using the specified `allocator` to supply memory. The behavior is undefined if `capacity` `DatumMapEntry` object plus `keysCapacity` would exceed the addressable memory for the platform. Note that the caller is responsible for filling in elements into the datum‐key‐owning map, copying the keys into it, and setting its size accordingly. The number of elements in the datum‐key‐owning map cannot exceed `capacity` and total size of all the keys cannot exceed `keysCapacity`. Also note that any elements in the datum‐key‐owning map that need dynamic memory, should also be allocated with `allocator`.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *result*
| receives the mutable key‐owning map reference
| *capacity*
| maximum number of entries the map can hold
| *keysCapacity*
| total key‐storage capacity in bytes
| *allocator*
| memory allocator to use
|===


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