std::is_object

 

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Defined in header <type_traits>
template< class T > struct is_object;		(since C++11)

If T is an object type (that is any possibly cv-qualified type other than function, reference, or void types), provides the member constant value equal true. For any other type, value is false.

The behavior of a program that adds specializations for is_object or is_object_v (since C++17) is undefined.

Template parameters

T

-

a type to check

Helper variable template

template< class T > inline constexpr bool is_object_v = is_object<T>::value;		(since C++17)

Inherited from std::integral_constant

Member constants

value [static]

true if T is an object 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>

Possible implementation

template< class T> struct is_object : std::integral_constant<bool, std::is_scalar<T>::value || std::is_array<T>::value || std::is_union<T>::value || std::is_class<T>::value> {};

Example

Run this code

#include <iostream>
#include <type_traits>
 
int main() {
    class cls {};
    std::cout << std::boolalpha;
    std::cout << std::is_object<int>::value << '\n';
    std::cout << std::is_object<int&>::value << '\n';
    std::cout << std::is_object<cls>::value << '\n';
    std::cout << std::is_object<cls&>::value << '\n';
}

Output:

true
false
true
false

See also

is_scalar (C++11)	checks if a type is a scalar type (class template)
is_array (C++11)	checks if a type is an array type (class template)
is_union (C++11)	checks if a type is an union type (class template)
is_class (C++11)	checks if a type is a non-union class type (class template)