std::literals::string_literals:: operator""s
|
Defined in header
<string>
|
||
|
std::
string
operator
""
s
(
const
char
*
str,
std::
size_t
len
)
;
|
(1) |
(since C++14)
(constexpr since C++20) |
|
constexpr
std::
u8string
operator
""
s
(
const
char8_t
*
str,
std::
size_t
len
)
;
|
(2) | (since C++20) |
|
std::
u16string
operator
""
s
(
const
char16_t
*
str,
std::
size_t
len
)
;
|
(3) |
(since C++14)
(constexpr since C++20) |
|
std::
u32string
operator
""
s
(
const
char32_t
*
str,
std::
size_t
len
)
;
|
(4) |
(since C++14)
(constexpr since C++20) |
|
std::
wstring
operator
""
s
(
const
wchar_t
*
str,
std::
size_t
len
)
;
|
(5) |
(since C++14)
(constexpr since C++20) |
Forms a string literal of the desired type.
Parameters
| str | - | pointer to the beginning of the raw character array literal |
| len | - | length of the raw character array literal |
Return value
The string literal.
Notes
These operators are declared in the namespace
std
::
literals
::
string_literals
, where both
literals
and
string_literals
are inline namespaces. Access to these operators can be gained with either
- using namespace std :: literals , or
- using namespace std :: string_literals , or
- using namespace std :: literals :: string_literals .
std::chrono::duration also defines operator "" s , to represent literal seconds, but it is an arithmetic literal: 10.0s and 10s are ten seconds, but "10" s is a string.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_string_udls
|
201304L | (C++14) | User-defined literals for string types |
Example
#include <iostream> #include <string> void print_with_zeros(auto const note, std::string const& s) { std::cout << note; for (const char c : s) c ? std::cout << c : std::cout << "₀"; std::cout << " (size = " << s.size() << ")\n"; } int main() { using namespace std::string_literals; std::string s1 = "abc\0\0def"; std::string s2 = "abc\0\0def"s; print_with_zeros("s1: ", s1); print_with_zeros("s2: ", s2); std::cout << "abcdef"s.substr(1,4) << '\n'; }
Output:
s1: abc (size = 3) s2: abc₀₀def (size = 8) bcde
See also
constructs a
basic_string
(public member function) |
|
|
(C++17)
|
creates a string view of a character array literal
(function) |