View source for cpp/ranges/borrowed iterator t

{{cpp/ranges/title|borrowed_iterator_t|borrowed_subrange_t}}
{{cpp/ranges/navbar}}

{{dcl begin}}
{{dcl header|ranges}}
{{dcla|num = 1|since = c++20|1 =
template< ranges::range R >
using borrowed_iterator_t = /* see below */;
}}
{{dcla|num = 2|since = c++20|1 =
template< ranges::range R >
using borrowed_subrange_t = /* see below */;
}}

{{dcl end}}

@1@ {{c|std::ranges::iterator_t<R>}} if {{tt|R}} models {{lconcept|borrowed_range}}, {{lc|std::ranges::dangling}} otherwise.

@2@ {{c|std::ranges::subrange<std::ranges::iterator_t<R>>}} if {{tt|R}} models {{lconcept|borrowed_range}}, {{lc|std::ranges::dangling}} otherwise.

These two alias templates are used by some [[cpp/algorithm/ranges|constrained algorithms]] to avoid returning potentially dangling iterators or views.

===Possible implementation===
{{eq impl
|title1=borrowed_iterator_t|ver1=1|1=
template< std::ranges::range R >
using borrowed_iterator_t = std::conditional_t<std::ranges::borrowed_range<R>,
    std::ranges::iterator_t<R>, std::ranges::dangling>;
|title2=borrowed_subrange_t|ver2=2|2=
template< std::ranges::range R >
using borrowed_subrange_t = std::conditional_t<std::ranges::borrowed_range<R>,
    std::ranges::subrange<std::ranges::iterator_t<R>>, std::ranges::dangling>;
}}

===See also===
{{dsc begin}}
{{dsc inc|cpp/ranges/dsc dangling}}
{{dsc end}}

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