< cpp‎ | experimental‎ | ranges
Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals 2 TS)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Concepts (concepts TS)
Ranges (ranges TS)
Special mathematical functions (special math TR)
Iterators library
Iterator concepts
Indirect callable concepts
Common algorithm requirements
Concept utilities
Iterator utilities and operations
Iterator traits
Iterator adaptors
Stream iterators
template <Readable I, IndirectRegularUnaryInvocable<I> Proj>

struct projected {
    using value_type =
    ranges::indirect_result_of_t<Proj&(I)> operator*() const;

template <WeaklyIncrementable I, class Proj>
struct difference_type<projected<I, Proj>> {
    using type = ranges::difference_type_t<I>;

(ranges TS)

The class template projected bundles a Readable type I and a function Proj into a new Readable type whose reference type is the result of applying Proj to the reference type of I. It exists solely to ease constraint specification, and so its operator*() may not be actually defined.