[#BloombergLP-bdlb-hashAppend-0d]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::hashAppend
:relfileprefix: ../../
:mrdocs:

Append the engaged state and value of `input` to `hashAlg`&period;

== Synopsis

Declared in `&lt;bdlb&lowbar;nullablevalueref&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template&lt;
    class HASHALG,
    class TYPE&gt;
void
hashAppend(
    HASHALG& hashAlg,
    xref:BloombergLP/bdlb/ConstNullableValueRef.adoc[ConstNullableValueRef&lt;TYPE&gt;] const& input);
----

== Description

Pass the boolean value of whether the specified `input` references a non&hyphen;empty nullable value to the specified `hashAlg` hashing algorithm of (template parameter) type `HASHALG`&period; If `input&period;has&lowbar;value` is true, additionally pass the value to `hashAlg`&period;

== Parameters

[cols="1,4"]
|===
| Name| Description
| *hashAlg*
| hashing algorithm to update
| *input*
| nullable wrapper to hash
|===


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