BloombergLP::bslstl::Optional_Base

Synopsis

Declared in <bslstl_optional.h>

template<
    class t_TYPE,
    bool t_USES_BSLMA_ALLOC = BloombergLP::bslma::UsesBslmaAllocator<t_TYPE>::value>
class Optional_Base;

Description

This component-private class template implements the functionality of bsl::optional. The primary template is instantiated when TYPE is allocator-aware, and holds the allocator that is used to create the stored object.

Type Aliases

Name	Description
`allocator_type`	This `typedef` is an alias to `bsl::allocator<char>`.
`value_type`	Alias for the managed object type of this optional.

Member Functions

Name	Description
`operator=`	Assignment operators
`emplace`	Destroy any contained value and construct a new one in place.
`get_allocator`	Return allocator used for construction of `value_type`.
`has_value`	Return `false` if this object is disengaged, and `true` otherwise.
`operator*`	Dereference operators
`operator->`	Member access operators
`reset`	Reset this object to the default constructed state (i.e., to a disengaged state).
`swap`	Exchange the values of two optionals.
`value`	`value` overloads
`value_or`	Return the contained value, or a converted fallback if disengaged.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, IsBitwiseCopyable, BloombergLP::bslmf::IsBitwiseCopyable<t_TYPE>::value>`	Nested trait declaration for `bslmf::IsBitwiseCopyable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, IsBitwiseMoveable, BloombergLP::bslmf::IsBitwiseMoveable<t_TYPE>::value>`	Nested trait declaration for `bslmf::IsBitwiseMoveable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, UsesAllocatorArgT>`	Nested trait declaration for `bslmf::UsesAllocatorArgT`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, UsesBslmaAllocator>`	Nested trait declaration for `bslma::UsesBslmaAllocator`.
`operator bool`	Return `false` if this object is disengaged, and `true` otherwise.

Protected Type Aliases

Name	Description
`AllocType`	This `typedef` is an alias to `allocator_type`.

Protected Member Functions

Name	Description
`Optional_Base` [constructor]	Constructors
`assignOrEmplace`	Assign or emplace a value into this optional.
`dereferenceRaw`	Return a reference to the contained value without checking engagement.

Specializations

Name	Description
`Optional_Base<t_TYPE, false>`	Specialization of `Optional_Base` for `value_type` that is not allocator-aware when `std::optional` is available.

Derived Classes

Name	Description
`optional`	Allocator-aware nullable wrapper for an object of type `t_TYPE`.