23 Strings library [strings]

23.4 String classes [string.classes]

23.4.7 Suffix for basic_string literals [basic.string.literals]

constexpr string operator""s(const char* str, size_t len);
Returns: string{str, len}.
constexpr u8string operator""s(const char8_t* str, size_t len);
Returns: u8string{str, len}.
constexpr u16string operator""s(const char16_t* str, size_t len);
Returns: u16string{str, len}.
constexpr u32string operator""s(const char32_t* str, size_t len);
Returns: u32string{str, len}.
constexpr wstring operator""s(const wchar_t* str, size_t len);
Returns: wstring{str, len}.
[Note 1: 
The same suffix s is used for chrono​::​duration literals denoting seconds but there is no conflict, since duration suffixes apply to numbers and string literal suffixes apply to character array literals.
— end note]