[#BloombergLP-bdlb-BitMaskUtil-zero64]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::xref:BloombergLP/bdlb/BitMaskUtil.adoc[BitMaskUtil]::zero64
:relfileprefix: ../../../
:mrdocs:

Return the unsigned integral value having the specified `numBits` starting at the specified `index` set to 0, and all other bits set to 1&period; The behavior is undefined unless `0 &lt;&equals; index`, `0 &lt;&equals; numBits`, and `index &plus; numBits &lt;&equals; &num; of bits in result`&period;

== Synopsis

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

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
uint64&lowbar;t
zero64(
    int index,
    int numBits);
----


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