See the first get overload above.
get
Declared in <bslstl_variant.h>
<bslstl_variant.h>
template< std::size_t t_INDEX, class t_HEAD, class... t_TAIL> variant_alternative<t_INDEX, variant<t_HEAD, t_TAIL...>>::type&& get(variant<t_HEAD, t_TAIL...>&& obj);