std::extent (3) Linux Manual Page
std::extent – std::extent Synopsis Defined in header<type_traits> template <class T, unsigned N = 0> (since C++ 11) struct extent; If T is an array type, provides the member constant value equal to the number of elements along the Nth dimension of the array, if N is in [0, std::rank<T>::value). For any other type, or if…
