string operator""s(const char* str, size_t len);
Returns:
string{str, len}.
u16string operator""s(const char16_t* str, size_t len);
Returns:
u16string{str, len}.
u32string operator""s(const char32_t* str, size_t len);
Returns:
u32string{str, len}.
wstring operator""s(const wchar_t* str, size_t len);
Returns:
wstring{str, len}.
[ Note:
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 ]