Boost.Hana: boost::hana::detail::index_if< Pred, Ts, typename > Struct Template Reference

| Boost.Hana 1.0.0 Your standard library for metaprogramming |

boost::hana::detail::index_if< Pred, Ts, typename > Struct Template Reference
Details

## 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`.