[#BloombergLP-bdlb-Variant12]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::Variant12
:relfileprefix: ../../
:mrdocs:

Fixed‐arity specialization of `Variant` for 12 types.

== Synopsis

Declared in `<bdlb_variant.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class A1,
    class A2,
    class A3,
    class A4,
    class A5,
    class A6,
    class A7,
    class A8,
    class A9,
    class A10,
    class A11,
    class A12>
class Variant12
    : public xref:BloombergLP/bdlb/VariantImp.adoc[VariantImp<bslmf::TypeList12<A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12>::ListType>]
----

== Description

Its 12 template arguments _must_ all be specified (none are defaulted to `bslmf::Nil`). It provides the same functionality as `Variant<A1, A2, ..., A12>`.

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/bdlb/VariantImp.adoc[VariantImp<bslmf::TypeList12<A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12>::ListType>]`
| This class provides the implementation of `Variant` (except for the creators) given a list of template parameter `TYPES`.
|===

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlb/Variant12/2constructor-082.adoc[`Variant12`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bdlb/Variant12/operator_assign-0d.adoc[`operator=`] 
| Assignment operators
| xref:BloombergLP/bdlb/Variant12/apply.adoc[`apply`] 
| `apply` overloads
| xref:BloombergLP/bdlb/Variant12/applyRaw.adoc[`applyRaw`] 
| `applyRaw` overloads
| xref:BloombergLP/bdlb/Variant12/assign.adoc[`assign`] 
| Assign the specified `TYPE` `value` to this object.
| xref:BloombergLP/bdlb/VariantImp/assignTo.adoc[`assignTo`] 
| Assign `value` converted to `TYPE` to this object.
| xref:BloombergLP/bdlb/VariantImp/bdexStreamIn.adoc[`bdexStreamIn`] 
| DEPRECATED: Do not use.
| xref:BloombergLP/bdlb/VariantImp/bdexStreamOut.adoc[`bdexStreamOut`] 
| DEPRECATED: Do not use.
| xref:BloombergLP/bdlb/VariantImp/createInPlace.adoc[`createInPlace`] 
| Emplace a `TYPE` instance constructed from `arguments`.
| xref:BloombergLP/bdlb/VariantImp/is.adoc[`is`] 
| Return whether this variant currently holds a `TYPE` value.
| xref:BloombergLP/bdlb/VariantImp/isUnset.adoc[`isUnset`] 
| Return whether this variant currently holds no value.
| xref:BloombergLP/bdlb/VariantImp/maxSupportedBdexVersion.adoc[`maxSupportedBdexVersion`] 
| DEPRECATED: Do not use.
| xref:BloombergLP/bdlb/VariantImp/print.adoc[`print`] 
| Format this object to the specified output `stream`.
| xref:BloombergLP/bdlb/VariantImp/reset.adoc[`reset`] 
| Destroy the current value held by this variant (if any), and reset this variant to the unset state.
| xref:BloombergLP/bdlb/VariantImp/swap.adoc[`swap`] 
| Swap the value of this object with `other`.
| xref:BloombergLP/bdlb/Variant12/the.adoc[`the`] 
| `the` overloads
| xref:BloombergLP/bdlb/VariantImp/typeIndex.adoc[`typeIndex`] 
| Return the 1‐based index of the held type, or 0 if unset.
| xref:BloombergLP/bdlb/VariantImp/typeInfo.adoc[`typeInfo`] 
| Return `typeid(void)`.
| xref:BloombergLP/bdlb/Variant12/2conversion-07.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant12, HasPrintMethod>`] 
| Nested trait declaration for `bdlb::HasPrintMethod`.
| xref:BloombergLP/bdlb/Variant12/2conversion-04.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant12, IsBitwiseCopyable, Traits::k_VARIANT_IS_BITWISE_COPYABLE>`] 
| Nested trait declaration for `bslmf::IsBitwiseCopyable`.
| xref:BloombergLP/bdlb/Variant12/2conversion-0d.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant12, IsBitwiseMoveable, Traits::k_VARIANT_IS_BITWISE_MOVEABLE>`] 
| Nested trait declaration for `bslmf::IsBitwiseMoveable`.
| xref:BloombergLP/bdlb/Variant12/2conversion-08.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant12, UsesBslmaAllocator, Traits::k_VARIANT_USES_BSLMA_ALLOCATOR>`] 
| Nested trait declaration for `bslma::UsesBslmaAllocator`.
| xref:BloombergLP/bdlb/VariantImp/2conversion-0e.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<VariantImp, HasPrintMethod>`] 
| Nested trait declaration for `bdlb::HasPrintMethod`.
| xref:BloombergLP/bdlb/VariantImp/2conversion-02.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<VariantImp, IsBitwiseCopyable, Traits::k_VARIANT_IS_BITWISE_COPYABLE>`] 
| Nested trait declaration for `bslmf::IsBitwiseCopyable`.
| xref:BloombergLP/bdlb/VariantImp/2conversion-05.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<VariantImp, IsBitwiseMoveable, Traits::k_VARIANT_IS_BITWISE_MOVEABLE>`] 
| Nested trait declaration for `bslmf::IsBitwiseMoveable`.
| xref:BloombergLP/bdlb/VariantImp/2conversion-04.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<VariantImp, UsesBslmaAllocator, Traits::k_VARIANT_USES_BSLMA_ALLOCATOR>`] 
| Nested trait declaration for `bslma::UsesBslmaAllocator`.
|===


== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlb/operator_not_eq-045.adoc[`operator!=`]
| Return whether `lhs` and `rhs` do not have the same value.
| xref:BloombergLP/bdlb/operator_eq-0101.adoc[`operator==`]
| Grant the equality comparison operator access to this class's private members.
| xref:BloombergLP/bdlb/operator_eq-0fc.adoc[`operator==`]
| Return whether `lhs` and `rhs` have the same value.
| xref:BloombergLP/bdlb/swap-04.adoc[`swap`]
| Swap the values of the specified `a` and `b` objects.
|===


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