24 Ranges library [ranges]

24.3 Range access [range.access]

24.3.10 ranges::ssize [range.prim.ssize]

The name ranges::ssize denotes a customization point object ([customization.point.object]).

The expression ranges::ssize(E) for a subexpression E of type T is expression-equivalent to:

(1.1)
If range_difference_t<T> has width less than ptrdiff_t, static_cast<ptrdiff_t>(ranges::
size(E)).
(1.2)
Otherwise, static_cast<range_difference_t<T>>(ranges::size(E)).