std::is_signed

 

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Template:ddcl list begin <tr class="t-dsc-header">

<td>

Defined in header <type_traits>

</td>

<td></td> <td></td> </tr> <tr class="t-dcl ">

<td >

template< class T >
struct is_signed;

</td>

<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> Template:ddcl list end

If T is a signed arithmetic type, provides the member constant value equal true. For any other type, value is false.

Inherited from std::integral_constant

Member constants

value [static]

true if T is a signed arithmetic type , false otherwise (public static member constant)

Member functions

operator bool	converts the object to bool, returns value (public member function)
operator() (C++14)	returns value (public member function)

Member types

Type	Definition
value_type	bool
type	std::integral_constant<bool, value>

Example

Run this code

#include <iostream>
#include <type_traits>
 
class A {};
enum B : int {};
enum class C : int {};
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_signed<A>::value << '\n';
    std::cout << std::is_signed<float>::value << '\n';
    std::cout << std::is_signed<signed int>::value << '\n';
    std::cout << std::is_signed<unsigned int>::value << '\n';
    std::cout << std::is_signed<B>::value << '\n';
    std::cout << std::is_signed<C>::value << '\n';
}

Output:

false
true
true
false
false
false

See also

is_unsigned (C++11)	checks if a type is an unsigned arithmetic type (class template)
is_signed [static]	identifies signed types (public static member constant of std::numeric_limits<T>)
is_floating_point (C++11)	checks if a type is a floating-point type (class template)
is_integral (C++11)	checks if a type is an integral type (class template)
make_signed (C++11)	obtains the corresponding signed type for the given integral type (class template)
make_unsigned (C++11)	obtains the corresponding signed type for the given integral type (class template)