Determine whether the unique best‐match alternative is assignable.

Synopsis

Declared in <bslstl_variant.h>

Description

This component‐private metafunction is derived from bsl::true_type if there is a unique best match alternative in (template parameter) t_VARIANT for std::declval<t_TYPE>() and that alternative is both constructible and assignable from std::declval<t_TYPE>(), and bsl::false_type otherwise.

Base Classes

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.

Specializations

Name

Description

Variant_isAlternativeAssignableFrom<t_VARIANT, t_TYPE, bsl::variant_npos>

Derive from bsl::false_type when there is no unique best match.

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