Difference between revisions of "cpp/ranges/borrowed iterator t"
From cppreference.com
(P1252R2 safe_iterator_t, safe_subrange_t) |
m (std::) |
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| Line 6: | Line 6: | ||
{{dcl | num = 1 | since = c++20 | 1 = | {{dcl | num = 1 | since = c++20 | 1 = | ||
template<Range R> | template<Range R> | ||
| − | using safe_iterator_t = conditional_t<__ForwardingRange<R>, | + | using safe_iterator_t = std::conditional_t<__ForwardingRange<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<Range R> | template<Range R> | ||
| − | using safe_subrange_t = conditional_t<__ForwardingRange<R>, | + | using safe_subrange_t = std::conditional_t<__ForwardingRange<R>, |
ranges::subrange<ranges::iterator_t<R>>, ranges::dangling>; | ranges::subrange<ranges::iterator_t<R>>, ranges::dangling>; | ||
}} | }} | ||
Revision as of 08:43, 9 May 2019
| Defined in header <ranges>
|
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| template<Range R> using safe_iterator_t = std::conditional_t<__ForwardingRange<R>, |
(1) | (since C++20) |
| template<Range R> using safe_subrange_t = std::conditional_t<__ForwardingRange<R>, |
(2) | (since C++20) |
1) Same as ranges::iterator_t when
R models exposition-only concept __ForwardingRange, 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) |
