24 Ranges library [ranges]

24.3 Range access [range.access]

24.3.4 ranges​::​cbegin [range.access.cbegin]

The name ranges​::​cbegin denotes a customization point object ([customization.point.object]).
The expression ranges​::​​cbegin(E) for a subexpression E of type T is expression-equivalent to:
  • ranges​::​begin(static_­cast<const T&>(E)) if E is an lvalue.
  • Otherwise, ranges​::​begin(static_­cast<const T&&>(E)).
[Note 1:
Whenever ranges​::​cbegin(E) is a valid expression, its type models input_­or_­output_­iterator.
— end note]