24 Ranges library [ranges]

24.3 Range access [range.access]

24.3.8 ranges​::​crend [range.access.crend]

The name ranges​::​crend denotes a customization point object ([customization.point.object]).
The expression ranges​::​​crend(E) for a subexpression E of type T is expression-equivalent to:
  • ranges​::​rend(static_­cast<const T&>(E)) if E is an lvalue.
  • Otherwise, ranges​::​rend(static_­cast<const T&&>(E)).
[Note
:
Whenever ranges​::​crend(E) is a valid expression, the types S and I of ranges​::​crend(E) and ranges​::​crbegin(E) model sentinel_­for<S, I>.
— end note
]