deduction guides for std::basic_string_view
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< cpp | string | basic string view
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
std::basic_string_view
(C++20)
(C++20)
(C++23)
Constants
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Deduction guides (C++20)
Defined in header
<string_view>
template< class It, class End >
basic_string_view( It, End ) -> basic_string_view<std::iter_value_t <It>>;
(1)
(since C++20)
basic_string_view( It, End ) -> basic_string_view<std::iter_value_t <It>>;
template< class R >
basic_string_view( R&& ) -> basic_string_view<ranges::range_value_t <R>>;
(2)
(since C++23)
basic_string_view( R&& ) -> basic_string_view<ranges::range_value_t <R>>;
These deduction guides are provided for std::basic_string_view .
1) This deduction guide allow the character type to be deduced from the iterator-sentinel pair. This overload participates in overload resolution only if
It satisfies contiguous_iterator and End satisfies sized_sentinel_for for It.2) This deduction guide allow the character type to be deduced from the range. This overload participates in overload resolution only if
R satisfies contiguous_range.[edit] Example
Run this code
#include <array> #include <iostream> #include <string_view> int main() { std::array a1{'n', 'u', 'c', 'l', 'e', 'o', 'n', 's', ':', '\n'}; std::basic_string_view s1(a1.cbegin(), a1.cend()); // deduction: CharT -> char static_assert(std::is_same_v <decltype(s1)::value_type, char>); std::cout << s1; std::array a2{L'p', L'r', L'o', L't', L'o', L'n', L's', L'\n'}; std::basic_string_view s2(a2.cbegin(), a2.cend()); // deduction: CharT -> wchar_t static_assert(std::is_same_v <decltype(s2)::value_type, wchar_t>); std::wcout << s2; std::array <long, 9> a3{'n', 'e', 'u', 't', 'r', 'o', 'n', 's', '\n'}; std::basic_string_view s3(a3.cbegin(), a3.cend()); // deduction: CharT -> long static_assert(std::is_same_v <decltype(s3)::value_type, long>); for (const auto e : s3) std::cout << static_cast<char>(e); }
Output:
nucleons: protons neutrons