NAME¶

std::literals::string_view_literals::operator""sv - std::literals::string_view_literals::operator""sv

Synopsis¶

Defined in header <string_view>
constexpr std::string_view (1) (since C++17)
operator ""sv( const char* str, std::size_t len ) noexcept;
constexpr std::u8string_view (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 ) (3) (since C++17)
noexcept;
constexpr std::u32string_view
operator ""sv( const char32_t* str, std::size_t len ) (4) (since C++17)
noexcept;
constexpr std::wstring_view (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}.

Parameters¶

str - pointer to the beginning of the raw character array literal
len - length of the raw character array literal

Return value¶

The std::basic_string_view literal.

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.

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' ? '@' : c);
std::cout << '\n';
}

int main()
{
using namespace std::literals;

std::string_view s1 = "abc\0\0def";
std::string_view s2 = "abc\0\0def"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

See also¶

constructor constructs a basic_string_view
(public member function)
operator""s converts a character array literal to basic_string
(C++14) (function)