BloombergLP::bdlb::Variant

Synopsis

Declared in <bdlb_variant.h>

template<class... TYPES>
class Variant
    : public VariantImp<bslmf::TypeList<TYPES...>::ListType>

Description

This class provides a "variant" type, i.e., a type capable of storing values from a list of template parameter types. Note that if the number N of types is smaller than 20, unused parameters default to bslmf::Nil, but it is more economical to use VariantN, which accepts exactly N template arguments, as this leads to shorter symbols and debug string information.

Base Classes

Name	Description
`VariantImp<bslmf::TypeList<TYPES...>::ListType>`	This class provides the implementation of `Variant` (except for the creators) given a list of template parameter `TYPES`.

Member Functions

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

Non-Member Functions

Name	Description
`operator!=`	Return whether `lhs` and `rhs` do not have the same value.
`operator==`	Grant the equality comparison operator access to this class's private members.
`operator==`	Return whether `lhs` and `rhs` have the same value.
`swap`	Swap the values of the specified `a` and `b` objects.