std::make_signed
Defined in header <type_traits> |
||
|---|---|---|
template< class T > struct make_signed; |
(since C++11) |
If T is an integral (except bool) or enumeration type, provides the member typedef type which is the signed integer type corresponding to T, with the same cv-qualifiers.
If T is signed or unsigned char, short, int, long, long long, the signed type from this list corresponding to T is provided.
If T is an enumeration type or char, wchar_t, char8_t (since C++20), char16_t, char32_t, the signed integer type with the smallest rank having the same sizeof as T is provided.
| Otherwise, the behavior is undefined. |
(until C++20) |
| Otherwise, the program is ill-formed. |
(since C++20) |
The behavior of a program that adds specializations for make_signed is undefined.
Member types
| Name | Definition |
|---|---|
type |
the signed integer type corresponding to T |
Helper types
template< class T > using make_signed_t = typename make_signed<T>::type; |
(since C++14) |
Example
#include <iostream>
#include <type_traits>
int main() {
typedef std::make_signed<unsigned char>::type char_type;
typedef std::make_signed<unsigned int>::type int_type;
typedef std::make_signed<volatile unsigned long>::type long_type;
bool ok1 = std::is_same<char_type, signed char>::value;
bool ok2 = std::is_same<int_type, signed int>::value;
bool ok3 = std::is_same<long_type, volatile signed long>::value;
std::cout << std::boolalpha
<< "char_type is 'signed char'? : " << ok1 << '\n'
<< "int_type is 'signed int'? : " << ok2 << '\n'
<< "long_type is 'volatile signed long'? : " << ok3 << '\n';
}
Output:
char_type is 'signed char'? : true int_type is 'signed int'? : true long_type is 'volatile signed long'? : true
See also
|
(C++11)
|
checks if a type is a signed arithmetic type (class template) |
|
(C++11)
|
checks if a type is an unsigned arithmetic type (class template) |
|
(C++11)
|
makes the given integral type unsigned (class template) |
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