25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.35 To input view [range.to.input]

25.7.35.1 Overview [range.to.input.overview]

to_input_view presents a view of an underlying sequence as an input-only non-common range.
[Note 1: 
This is useful to avoid overhead that can be necessary to provide support for the operations needed for greater iterator strength.
— end note]
The name views​::​to_input denotes a range adaptor object ([range.adaptor.object]).
Let E be an expression and let T be decltype((E)).
The expression views​::​to_input(E) is expression-equivalent to: