std::experimental::ranges::dangling, std::experimental::ranges::safe_iterator_t

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Extensions for concurrency 2 (concurrency TS v2)

Concepts (concepts TS)

Ranges (ranges TS)

Reflection (reflection TS)

Mathematical special functions (special functions TR)

 

Ranges

Concepts

General utilities

Iterators

Ranges

Algorithms

 

Iterators library

Iterator concepts
Readable Writable WeaklyIncrementable Incrementable	Iterator Sentinel SizedSentinel	InputIterator ForwardIterator BidirectionalIterator RandomAccessIterator	OutputIterator
Indirect callable concepts
IndirectUnaryInvocableIndirectRegularUnaryInvocable	IndirectUnaryPredicate	IndirectRelation	IndirectStrictWeakOrder
Common algorithm requirements
IndirectlyMovable IndirectlyMovableStorable	IndirectlyCopyable IndirectlyCopyableStorable	IndirectlySwappable IndirectlyComparable	Permutable Mergeable Sortable
Concept utilities
indirect_result_of	projected
Iterator utilities and operations
iter_move iter_swap	advance distance	next prev
Iterator traits
difference_type value_type reference_trvalue_reference_titer_common_reference_t iterator_category	input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tag	ranges::iterator_traits std::iterator_traits<InputIterator>std::iterator_traits<OutputIterator>
Iterator adaptors
reverse_iterator move_iterator move_sentinel	back_insert_iterator front_insert_iterator insert_iterator	common_iterator counted_iterator default_sentinel	danglingborrowed_iterator_t unreachable
Stream iterators
istream_iterator	ostream_iterator	istreambuf_iterator	ostreambuf_iterator

 

Defined in header <experimental/ranges/iterator>
template< CopyConstructible T > class dangling { public:     dangling() requires DefaultConstructible<T>();     dangling(T t);     T get_unsafe() const; };		(ranges TS)
template< Range R > using safe_iterator_t = std::conditional_t<std::is_lvalue_reference<R>::value,                                            ranges::iterator_t<R>,                                            ranges::dangling<ranges::iterator_t<R>>;		(ranges TS)

The class template dangling is a simple wrapper around an object to indicate that the wrapped object may be dangling, that is, it refers to another object whose lifetime may have ended.

The alias template safe_iterator_t returns the iterator type of R, wrapped in dangling if the range was an rvalue range (as indicated by R not being an lvalue reference type).

They are used by range algorithms that accept rvalue ranges and return iterators into them.

Member functions

std::experimental::ranges::dangling::dangling

dangling() requires DefaultConstructible<T>();	(1)
dangling(T t);	(2)

1) Default constructor. Value-initializes the wrapped object.

2) Initializes the wrapped object with t. Note that this constructor defines an implicit conversion from T to dangling<T>.

std::experimental::ranges::dangling::get_unsafe

T get_unsafe() const;

Returns a copy of the wrapped object.