[#BloombergLP-bslstl-Optional_Data-0c]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::Optional_Data
:relfileprefix: ../../
:mrdocs:

This component‐private `struct` manages a `value_type` object in `Optional_Base` by inheriting from `Optional_DataImp`. In addition, this primary template properly destroys the owned instance of `t_TYPE` in its destructor.

== Synopsis

Declared in `<bslstl_optional.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class t_TYPE,
    bool t_IS_TRIVIALLY_DESTRUCTIBLE = bslstl::Optional_IsTriviallyDestructible<t_TYPE>::value>
struct Optional_Data
    : xref:BloombergLP/bslstl/Optional_DataImp.adoc[Optional_DataImp<t_TYPE>]
----

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/bslstl/Optional_DataImp.adoc[Optional_DataImp<t_TYPE>]`
| This component‐private `struct` manages a `value_type` object in an `Optional_Base` object. This class provides an abstraction for `const` value type. An `Optional_Base` object may contain an object of `const` type. An assignment to such an `Optional_Base` object should not succeed. However, unless the `Optional_Base` object itself is `const`, it should be possible to change the value of the `Optional_Base` object using `emplace`. In order to allow for that, this class manages a non‐const object of `value_type`, but all the accessors return a `const` adjusted reference to the managed object.
|===

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Optional_Data-0c/2destructor.adoc[`~Optional_Data`] [.small]#[destructor]#
| Destroy the managed `value_type` object, if it exists.
| xref:BloombergLP/bslstl/Optional_DataImp/emplace-09.adoc[`emplace`] 
| `emplace` overloads
| xref:BloombergLP/bslstl/Optional_DataImp/hasValue.adoc[`hasValue`] 
| Return `true` if this objects has a value, and `false` otherwise.
| xref:BloombergLP/bslstl/Optional_DataImp/reset.adoc[`reset`] 
| Destroy the `value_type` object in `d_buffer`, if any.
| xref:BloombergLP/bslstl/Optional_DataImp/value-0c.adoc[`value`] 
| `value` overloads
|===


== Using Declarations

[cols="1"]
|===
| Name
| xref:BloombergLP/bslstl/Optional_Data-0c/_10using.adoc[`Unnamed using`] 
|===


== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Optional_Data-09.adoc[`Optional_Data<t_TYPE, true>`] 
| This partial specialization manages a trivially destructible `value_type` in Optional_Base. It does not have a user‐provided destructor, which makes it `is_trivially_destructible` itself.
|===



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