BloombergLP::bslstl::Variant_Base

Synopsis

Declared in <bslstl_variant.h>

template<
    class t_HEAD,
    class... t_TAIL>
struct Variant_Base
    : BloombergLP::bslstl::Variant_AllocatorBase<BloombergLP::bslstl::Variant_UsesBslmaAllocatorAny<t_HEAD, t_TAIL...>::value>

Description

This component-private struct defines the data representation of bsl::variant and contains the implementations of its special member functions (which must be defaulted in bsl::variant itself).

This class also contains implementations of additional constructors and methods needed for the correct functionality of the variant class hierarchy.

Base Classes

Name	Description
`BloombergLP::bslstl::Variant_AllocatorBase<BloombergLP::bslstl::Variant_UsesBslmaAllocatorAny<t_HEAD, t_TAIL...>::value>`	This component-private struct keeps track of the allocator for a `bsl::variant` object.

Types

Name	Description
`NoAlloc`	This trivial tag type is used as a dummy when `Variant_Base` wraps a non-allocator-aware type.

Type Aliases

Name	Description
`AllocBase`	Base class providing allocator support when needed.
`MoveUtil`	Utility for movable reference operations.
`Variant`	Corresponding public `bsl::variant` type.
`Variant_Union`	Union holding the active alternative objects.
`allocator_type`	Type alias to the allocator type used by `variant`.

Member Functions

Name	Description
`Variant_Base` [constructor]	Constructors
`~Variant_Base` [destructor]	Destroy this object. The contained value, if any, is destroyed.
`operator=`	Assignment operators
`baseEmplace`	Create the alternative with index (template parameter) `t_INDEX` in place, direct-initialized from the specified `args`.
`mechanism`	Return a null pointer.
`reset`	Destroy the contained value, if any.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant_Base, IsBitwiseMoveable, (BloombergLP::bslstl::Variant_IsBitwiseMoveableAll<t_HEAD, t_TAIL...>::value)>`	Nested trait declaration for `IsBitwiseMoveable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant_Base, UsesAllocatorArgT, (BloombergLP::bslstl::Variant_UsesBslmaAllocatorAny<t_HEAD, t_TAIL...>::value)>`	Nested trait declaration for `UsesAllocatorArgT`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Variant_Base, UsesBslmaAllocator, (BloombergLP::bslstl::Variant_UsesBslmaAllocatorAny<t_HEAD, t_TAIL...>::value)>`	Nested trait declaration for `UsesBslmaAllocator`.

Data Members

Name	Description
`d_type`	Index of the currently active alternative in this variant object, or `bsl::variant_npos` if the variant is valueless by exception.
`d_union`	Union holding the alternative object.