[#BloombergLP-bsls-AlignmentUtil-calculateAlignmentFromSize]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bsls.adoc[bsls]::xref:BloombergLP/bsls/AlignmentUtil.adoc[AlignmentUtil]::calculateAlignmentFromSize
:relfileprefix: ../../../
:mrdocs:

Return the natural alignment for a memory block of the specified size.

== Synopsis

Declared in `<bsls_alignmentutil.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
int
calculateAlignmentFromSize(std::size_t size);
----

== Description

Return the _natural_ alignment for a memory block of the specified size ‐‐ i.e., the largest power of 2 that evenly divides `size`, up to a maximum of `BSLS_MAX_ALIGNMENT`. It is guaranteed that this alignment will be sufficient for any object having a footprint of `size` bytes on the current platform. The behavior is undefined unless `1 <= size` and `size <= INT_MAX`. Note that, depending on the machine architecture and compiler setting, the returned alignment value may be more restrictive than required for a particular object for two reasons: 1. The object may be composed entirely of elements, such as `char`, that have minimal alignment restrictions, and 2. The architecture and our compiler settings may result in unexpectedly lenient alignment requirements. Also note that aligning on a more restrictive boundary may improve performance.

== Return Value

natural alignment for a block of `size` bytes

== Parameters

[cols="1,4"]
|===
| Name| Description
| *size*
| size in bytes of the memory block
|===


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