Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Global tuple_size_v

boost::pfr::tuple_size_v

// In header: <boost/pfr/tuple_size.hpp>

constexpr std::size_t tuple_size_v;

tuple_size_v is a template variable that contains fields count in a T and works for any T that supports aggregate initialization.

Example:

std::array<int, boost::pfr::tuple_size_v<my_structure> > a;