[indirectcallable.traits] (original) (raw)

24 Iterators library [iterators]

24.3 Iterator requirements [iterator.requirements]

24.3.6 Indirect callable requirements [indirectcallable]

24.3.6.2 Indirect callable traits [indirectcallable.traits]

To implement algorithms taking projections, it is necessary to determine the projected type of an iterator's value type.

For the exposition-only alias template indirect-value-t,indirect-value-t<T> denotes

• invoke_result_t<Proj&, _indirect-value-t_<I>>if T names projected<I, Proj>, and
• iter_value_t<T>& otherwise.