On 17/10/18 15:06 +0300, Ville Voutilainen wrote:
On Wed, 17 Oct 2018 at 12:20, Ville Voutilainen <ville.voutilai...@gmail.com> wrote:On Wed, 17 Oct 2018 at 12:07, Jonathan Wakely <jwak...@redhat.com> wrote: > It might be worth also calling f<256>() and doing: > > template <std::size_t... Is> > void f_impl(std::index_sequence<Is...> is) > { > using V = std::variant<S<Is>...>; > > // For a variant of 255 alternatives the valid indices are [0,254] > // and index 255 means valueless-by-exception, so fits in one byte. > if constexpr (std::variant_size_v<V> <= 255) > static_assert(sizeof(V) == 2) > else > static_assert(sizeof(V) > 2) > } > > Just to check we don't introduce an off-by-one error in the *other* > direction in future. What do you think? Agreed. I'll patch that in. > To be really portable we would use numeric_limits<unsigned char>::max() > but we don't need to worry about non-8-bit char in our implementation. I can change that as well so that we don't need to re-think it every time.Here.
Great, thanks for the changes - OK for trunk.
