BloombergLP::bslstl::Variant_HasUniqueType<t_TYPE, bsl::variant<t_HEAD, t_TAIL...>>

Synopsis

Declared in <bslstl_variant.h>

template<
    class t_TYPE,
    class t_HEAD,
    class... t_TAIL>
struct Variant_HasUniqueType<t_TYPE, bsl::variant<t_HEAD, t_TAIL...>>
    : bsl::integral_constant<bool, Variant_CountType<t_TYPE, t_HEAD, t_TAIL...>::value == 1>

Description

This partial specialization of Variant_HasUniqueType derives from bsl::true_type if t_TYPE occurs exactly once in the alternatives t_HEAD, t_TAIL... of a bsl::variant specialization.

Base Classes

Name	Description
`bsl::integral_constant<bool, Variant_CountType<t_TYPE, t_HEAD, t_TAIL...>::value == 1>`	Metafunction representing a compile-time constant of the specified (template parameter) `t_TYPE` with the specified (template parameter) `t_VALUE`.

Type Aliases

Name	Description
`type`	Alias for this `integral_constant` specialization.
`value_type`	Alias for the (template parameter) `t_TYPE`.

Member Functions

Name	Description
`operator()`	Return a copy of the template argument `t_VALUE`.
`operator t_TYPE`	Return a copy of the template argument `t_VALUE`.

Static Data Members

Name	Description
`value`	The compile-time constant value of this metafunction.