Function unload

include/boost/leaf/context.hpp:438–443

    }

    void unload(error_id id) noexcept(!BOOST_LEAF_CFG_CAPTURE)
    {
        BOOST_LEAF_ASSERT(!is_active());
        tls::write_current_error_id(static_cast<unsigned>(id.value()));
        detail::tuple_for_each<std::tuple_size<Tup>::value,Tup>::unload(tup_, id.value());
    }

    BOOST_LEAF_CONSTEXPR bool is_active() const noexcept
    {