[#bsl-optional-072-2constructor-09c]
= xref:bsl.adoc[bsl]::xref:bsl/optional-072.adoc[optional]::optional
:relfileprefix: ../../
:mrdocs:

Create a disengaged `optional` object if the specified `original` object is disengaged, and an `optional` object with the value of `original.value()`.

== Synopsis

Declared in `<bslstl_optional.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class t_ANY_TYPE>
optional(
    std::allocator_arg_t allocatorArg,
    xref:bsl/optional-072.adoc[AllocType] allocator,
    std::optional<t_ANY_TYPE> const& original);
----

== Description

Create a disengaged `optional` object if the specified `original` object is disengaged, and an `optional` object with the value of `original.value()` converted

Create a disengaged `optional` object if the specified `original` object is disengaged, and an `optional` object with the value of `original.value()` converted to `t_TYPE` otherwise. Use the specified `allocator` to supply memory. Note that this constructor participates in overload resolution only when `t_TYPE` is constructible from an lvalue of `const t_ANY_TYPE`, and is implicit only when an lvalue of `const t_ANY_TYPE` is implicitly convertible to `t_TYPE`.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *allocatorArg*
| tag selecting the allocator‐extended constructor
| *allocator*
| allocator used to supply memory
| *original*
| source optional used to initialize this object
|===


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