std::ranges...ge::subrange(3) C++ Standard Libary std::ranges...ge::subrange(3) NAME std::ranges::subrange::subrange - std::ranges::subrange::subrange Synopsis subrange() requires std::default_initializable<I> = default; (1) (since C++20) constexpr subrange( /*convertible-to-non-slicing*/<I> auto i, S s ) (2) (since requires (!/*store-size*/); C++20) constexpr subrange( /*convertible-to-non-slicing*/<I> auto i, S s, /*make-unsigned-like-t*/<std::iter_difference_t<I>> (3) (since n ) C++20) requires (K == ranges::subrange_kind::sized); template< /*different-from*/<subrange> R > requires ranges::borrowed_range<R> && /*convertible-to-non-slicing*/<ranges::iterator_t<R>, I> && (4) (since std::convertible_to<ranges::sentinel_t<R>, S> C++20) constexpr subrange( R&& r ) requires (!/*store-size*/ || ranges::sized_range<R>); template< ranges::borrowed_range R> requires /*convertible-to-non-slicing*/<ranges::iterator_t<R>, I> && std::convertible_to<ranges::sentinel_t<R>, S> constexpr subrange( R&& r, (5) (since /*make-unsigned-like-t*/<std::iter_difference_t<I>> n ) C++20) requires (K == ranges::subrange_kind::sized) : subrange{ranges::begin(r), ranges::end(r), n} {} Constructs a subrange. If K == ranges::subrange_kind::sized && !std::sized_sentinel_for<S, I>, the size of the range is stored into the subrange, as if stored by a member subob- ject of type /*make-unsigned-like-t*/<std::iter_difference_t<I>>, where make-un- signed-like-t is an exposition-only alias template that maps each integer-like type to its corresponding unsigned version. Otherwise, the size is not stored. The constant store-size is true if the size is stored, false otherwise. 1) Default constructor. Value-initializes the stored iterator and sen- tinel as if by default member initializers = I() and = S(), respectively. If the size is stored, it is initialized with 0 as if by the default member initializer = 0. 2) Constructs a subrange from an iterator-sentinel pair. Initializes the stored iterator and sentinel with std::move(i) and s respectively. The behavior is undefined if [i, s) is not a valid range. 3) Constructs a subrange from an iterator-sentinel pair and a size hint. Initializes the stored iterator and sentinel with std::move(i) and s respectively. If the size is stored, it is initialized with n. The behavior is undefined if [i, s) is not a valid range, or n is not equal to ranges::distance(i, s) explicitly con- verted to its type. 4) Constructs a subrange from a range. Equivalent to subrange(r, static_cast</*make-unsigned-like-t*/<std::iter_differ- ence_t<I>>>(ranges::size(r))) if the size is stored. Otherwise, equivalent to subrange(ranges::be- gin(r), ranges::end(r)). 5) Constructs a subrange from a range and a size hint. The behavior is undefined if n is not equal to ranges::distance(ranges::begin(r), ranges::end(r)) ex- plicitly converted to its type. The exposition only concept different-from is modeled by types T and U if and only if std::decay_t<T> and std::decay_t<U> are different types. The exposition only concept convertible-to-non-slicing is satisfied or modeled by From and To if and only if std::convertible_to<From, To> is satisfied or modeled respectively, and any of following conditions is satisfied: * either std::decay_t<From> or std::decay_t<To> is not a pointer type, * std::remove_pointer_t<From>(*)[] is implicitly convertible to std::remove_pointer_t<To>(*)[], i.e., the conversion from From to To is at most a qualification conversion. Parameters i - iterator that denotes the beginning of the range s - sentinel that denotes the end of the range r - range n - size hint, must be equal to the size of the range Notes The exposition-only concept convertible-to-non-slicing forbids the con- version from the pointer to derived class to the pointer to base class. Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Cor- rect behavior LWG 3470 C++20 convertible-to-non-slicing rejected some valid made accepted qualification conversions P2393R1 C++20 implicit conversion to an integer-class type made explicit might be invalid Example This section is incomplete Reason: no example Category: * Todo no example http://cppreference.com 2024.06.10 std::ranges...ge::subrange(3)
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