24 Ranges library [ranges]

24.3 Range access [range.access]

24.3.12 ranges​::​cdata [range.prim.cdata]

The name cdata denotes a customization point object.
The expression ranges​::​cdata(E) for some subexpression E of type T is expression-equivalent to:
  • ranges​::​data(static_­cast<const T&>(E)) if E is an lvalue.
  • Otherwise, ranges​::​data(static_­cast<const T&&>(E)).
Note
:
Whenever ranges​::​cdata(E) is a valid expression, it has pointer to object type.
— end note
 ]