std::literals::string_view_literals::operator""sv
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std::basic_string_view
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Constants
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
operator""sv
Deduction guides (C++20)
Defined in header
<string_view>
constexpr std::string_view
operator ""sv( const char* str, std::size_t len ) noexcept;
(1)
(since C++17)
operator ""sv( const char* str, std::size_t len ) noexcept;
constexpr std::u8string_view
operator ""sv( const char8_t* str, std::size_t len ) noexcept;
(2)
(since C++20)
operator ""sv( const char8_t* str, std::size_t len ) noexcept;
constexpr std::u16string_view
operator ""sv( const char16_t* str, std::size_t len ) noexcept;
(3)
(since C++17)
operator ""sv( const char16_t* str, std::size_t len ) noexcept;
constexpr std::u32string_view
operator ""sv( const char32_t* str, std::size_t len ) noexcept;
(4)
(since C++17)
operator ""sv( const char32_t* str, std::size_t len ) noexcept;
constexpr std::wstring_view
operator ""sv( const wchar_t* str, std::size_t len ) noexcept;
(5)
(since C++17)
operator ""sv( const wchar_t* str, std::size_t len ) noexcept;
Forms a string view of a character literal.
1) Returns std::string_view {str, len}.
2) Returns std::u8string_view {str, len}.
3) Returns std::u16string_view {str, len}.
4) Returns std::u32string_view {str, len}.
5) Returns std::wstring_view {str, len}.
Contents
[edit] Parameters
str
-
pointer to the beginning of the raw character array literal
len
-
length of the raw character array literal
[edit] Return value
The std::basic_string_view literal.
[edit] Notes
These operators are declared in the namespace std::literals::string_view_literals, where both literals and string_view_literals are inline namespaces. Access to these operators can be gained with any of:
- using namespace std::literals,
- using namespace std::string_view_literals, or
- using namespace std::literals::string_view_literals.
[edit] Example
Run this code
#include <iostream> #include <string_view> #include <typeinfo> void print_each_character(const std::string_view sw) { for (char c : sw) std::cout << (c == '0円' ? '@' : c); std::cout << '\n'; } int main() { using namespace std::literals; std::string_view s1 = "abc0円0円def"; std::string_view s2 = "abc0円0円def"sv; std::cout << "s1.size(): " << s1.size() << "; s1: "; print_each_character(s1); std::cout << "s2.size(): " << s2.size() << "; s2: "; print_each_character(s2); std::cout << "substr(1, 4): " << "abcdef"sv.substr(1, 4) << '\n'; auto value_type_info = []<typename T>(T) { using V = typename T::value_type; std::cout << "sizeof " << typeid(V).name() << ": " << sizeof(V) << '\n'; }; value_type_info("char A"sv); value_type_info(L"wchar_t ∀"sv); value_type_info(u8"char8_t ∆"sv); value_type_info(u"char16_t ∇"sv); value_type_info(U"char32_t ∃"sv); value_type_info(LR"(raw ⊞)"sv); }
Possible output:
s1.size(): 3; s1: abc s2.size(): 8; s2: abc@@def substr(1, 4): bcde sizeof char: 1 sizeof wchar_t: 4 sizeof char8_t: 1 sizeof char16_t: 2 sizeof char32_t: 4 sizeof wchar_t: 4