Difference between revisions of "cpp/ranges/borrowed iterator t"
From cppreference.com
m (P1870R1 safe_range) |
m (Text replace - "safe_(range|subrange|iterator)" to "borrowed_$1") |
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| − | {{cpp/ranges/title | | + | {{cpp/ranges/title | borrowed_iterator_t | borrowed_subrange_t}} |
{{cpp/ranges/navbar}} | {{cpp/ranges/navbar}} | ||
| Line 6: | Line 6: | ||
{{dcl | num = 1 | since = c++20 | 1 = | {{dcl | num = 1 | since = c++20 | 1 = | ||
template<ranges::range R> | template<ranges::range R> | ||
| − | using | + | using borrowed_iterator_t = std::conditional_t<ranges::borrowed_range<R>, |
ranges::iterator_t<R>, ranges::dangling>; | ranges::iterator_t<R>, ranges::dangling>; | ||
}} | }} | ||
{{dcl | num = 2 | since = c++20 | 1 = | {{dcl | num = 2 | since = c++20 | 1 = | ||
template<ranges::range R> | template<ranges::range R> | ||
| − | using | + | using borrowed_subrange_t = std::conditional_t<ranges::borrowed_range<R>, |
ranges::subrange<ranges::iterator_t<R>>, ranges::dangling>; | ranges::subrange<ranges::iterator_t<R>>, ranges::dangling>; | ||
}} | }} | ||
| Line 17: | Line 17: | ||
{{dcl end}} | {{dcl end}} | ||
| − | @1@ Same as {{ltt|cpp/ranges/iterator_t|ranges::iterator_t}} when {{tt|R}} models {{lconcept| | + | @1@ Same as {{ltt|cpp/ranges/iterator_t|ranges::iterator_t}} when {{tt|R}} models {{lconcept|borrowed_range}}, otherwise yields {{ltt|cpp/ranges/dangling|ranges::dangling}} instead. |
@2@ Similar to {{v|1}}, but it yields a specialization of {{ltt|cpp/ranges/subrange|ranges::subrange}} when the the same condition is met. | @2@ Similar to {{v|1}}, but it yields a specialization of {{ltt|cpp/ranges/subrange|ranges::subrange}} when the the same condition is met. | ||
Revision as of 05:26, 19 February 2020
| Defined in header <ranges>
|
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| template<ranges::range R> using borrowed_iterator_t = std::conditional_t<ranges::borrowed_range<R>, |
(1) | (since C++20) |
| template<ranges::range R> using borrowed_subrange_t = std::conditional_t<ranges::borrowed_range<R>, |
(2) | (since C++20) |
1) Same as ranges::iterator_t when
R models borrowed_range, otherwise yields ranges::dangling instead.2) Similar to (1), but it yields a specialization of ranges::subrange when the the same condition is met.
These two alias templates are used by some constrained algorithms to avoid returning potentially dangling iterators or views.
See also
| (C++20) |
a placeholder type indicating that an iterator or a subrange should not be returned since it would be dangling (class) |
