Boost.Hana  1.1.0
Your standard library for metaprogramming
boost::hana::detail::index_if< Pred, Ts, typename > Struct Template Reference

Description

template<typename Pred, typename Ts, typename = when<true>>
struct boost::hana::detail::index_if< Pred, Ts, typename >

Returns the index of the first element of the pack<> that satisfies the predicate, or the size of the pack if there is no such element.

Note
The predicate must return an IntegralConstant that can be explicitly converted to bool.