[#BloombergLP-bslstl-Variant_Base-2constructor-08d]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::xref:BloombergLP/bslstl/Variant_Base.adoc[Variant_Base]::Variant_Base
:relfileprefix: ../../../
:mrdocs:

Constructors

== Synopses

Declared in `<bslstl_variant.h>`

Create a `Variant_Base` object holding the 0th alternative, which is value‐initialized.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-00.adoc[Variant_Base]();
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-00.adoc[_» more..._]#

Create a `Variant_Base` object holding the same alternative (if any) as the specified `original` object.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-0f.adoc[Variant_Base](xref:BloombergLP/bslstl/Variant_Base.adoc[Variant_Base] const& original);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-0f.adoc[_» more..._]#

Create a `Variant_Base` object holding the same alternative (if any) held by the specified `original`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-0b9.adoc[Variant_Base](xref:BloombergLP/bslstl/Variant_Base.adoc[Variant_Base]&& original);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-0b9.adoc[_» more..._]#

Create a `Variant_Base` object whose index is the specified `index` without constructing an alternative object.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-05.adoc[Variant_Base](
    xref:BloombergLP/bslstl/Variant_ConstructFromStdTag.adoc[Variant_ConstructFromStdTag] fromStdTag,
    size_t index);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-05.adoc[_» more..._]#

Create a `Variant_Base` object holding the 0th alternative, which is value‐initialized.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-0bb.adoc[Variant_Base](
    std::allocator_arg_t allocatorArg,
    xref:BloombergLP/bslstl/Variant_Base/allocator_type.adoc[allocator_type] allocator);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-0bb.adoc[_» more..._]#

Create a `Variant_Base` object holding the alternative with index (template parameter) `t_INDEX`, direct‐initialized from the specified `args`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    size_t t_INDEX,
    class... t_ARGS>
explicit
xref:BloombergLP/bslstl/Variant_Base/2constructor-02.adoc[Variant_Base](
    bsl::in_place_index_t<t_INDEX> inPlaceIndex,
    t_ARGS&&... args);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-02.adoc[_» more..._]#

Create a `Variant_Base` object holding the same alternative (if any) held by the specified `original` object.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-089.adoc[Variant_Base](
    std::allocator_arg_t allocatorArg,
    xref:BloombergLP/bslstl/Variant_Base/allocator_type.adoc[allocator_type] allocator,
    xref:BloombergLP/bslstl/Variant_Base/Variant.adoc[Variant] const& original);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-089.adoc[_» more..._]#

See the corresponding copy constructor above.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-0e.adoc[Variant_Base](
    std::allocator_arg_t allocatorArg,
    xref:BloombergLP/bslstl/Variant_Base/allocator_type.adoc[allocator_type] allocator,
    xref:BloombergLP/bslstl/Variant_Base/Variant.adoc[Variant]&& original);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-0e.adoc[_» more..._]#

Create a `Variant_Base` object whose index is the specified `index` without constructing an alternative object.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:BloombergLP/bslstl/Variant_Base/2constructor-0b4.adoc[Variant_Base](
    std::allocator_arg_t allocatorArg,
    xref:BloombergLP/bslstl/Variant_Base/allocator_type.adoc[allocator_type] allocator,
    xref:BloombergLP/bslstl/Variant_ConstructFromStdTag.adoc[Variant_ConstructFromStdTag] fromStdTag,
    size_t index);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-0b4.adoc[_» more..._]#

Create a `Variant_Base` object holding the alternative with index (template parameter) `t_INDEX`, direct‐initialized from the specified `args`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    size_t t_INDEX,
    class... t_ARGS>
explicit
xref:BloombergLP/bslstl/Variant_Base/2constructor-04.adoc[Variant_Base](
    std::allocator_arg_t allocatorArg,
    xref:BloombergLP/bslstl/Variant_Base/allocator_type.adoc[allocator_type] allocator,
    bsl::in_place_index_t<t_INDEX> inPlaceIndex,
    t_ARGS&&... args);
----

[.small]#xref:BloombergLP/bslstl/Variant_Base/2constructor-04.adoc[_» more..._]#

== Parameters

[cols="1,4"]
|===
| Name| Description
| *original*
| object to copy
| *fromStdTag*
| tag selecting this indexless construction overload
| *index*
| index of the alternative that will (later) be created
| *allocatorArg*
| tag selecting the allocator‐extended overload
| *allocator*
| allocator used to supply memory
| *inPlaceIndex*
| tag selecting the in‐place‐index constructor
| *args*
| arguments forwarded to the alternative's constructor
|===


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