This component-private metafunction provides a member typedef Index representing the value that should be computed by Variant_ConvertIndex.
Declared in <bslstl_variant.h>
template<
class t_SRC,
class t_VARIANT,
class = void>
struct Variant_OverloadHelper;This component-private metafunction provides a member typedef Index representing the value that should be computed by Variant_ConvertIndex. The primary template is instantiated when the partial specialization below is not viable because no viable alternative exists for the conversion or because the best match is not "unique" (see the documentation of Variant_ConvertIndex for an explanation).
| Name | Description |
|---|---|
Index | Index constant equal to variant_npos when no unique conversion exists. |
| Name | Description |
|---|---|
Variant_OverloadHelper<t_SRC, bsl::variant<t_HEAD, t_TAIL...>, bsl::void_t<decltype(Variant_OverloadSetImp<t_SRC, 0, t_HEAD, t_TAIL...>::
candidate(std::declval<t_SRC>()))>> | Provide Index when a unique best-match alternative is found. |