[#BloombergLP-bslstl-Optional_ImmovableHelper]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::Optional&lowbar;ImmovableHelper
:relfileprefix: ../../
:mrdocs:

Helper enabling in&hyphen;place construction of immovable values&period;

== Synopsis

Declared in `&lt;bslstl&lowbar;optional&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template&lt;
    class t&lowbar;TYPE,
    class t&lowbar;INVOCABLE,
    class t&lowbar;ARG&gt;
struct Optional&lowbar;ImmovableHelper;
----

== Description

Helper enabling in&hyphen;place construction of immovable values&period;

This struct is used to implement direct initialization of the private data member of the `std&colon;&colon;optional` class, which makes it possible to support immovable types returned from the `transform` member function&period;

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Optional_ImmovableHelper/2conversion.adoc[`operator t&lowbar;TYPE`] 
| Invoke `invocable` with `arg` and return the result as `t&lowbar;TYPE`&period;
|===


== Data Members

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Optional_ImmovableHelper/arg.adoc[`arg`] 
| argument forwarded to `invocable`
| xref:BloombergLP/bslstl/Optional_ImmovableHelper/invocable.adoc[`invocable`] 
| callable invoked to produce the result
|===



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