23 Ranges library [ranges]

23.4 Range primitives [range.prim]

23.4.4 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
]