std::is_object - cppreference.com

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# std::is_object

From cppreference.com
< cpp‎ | types

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.

### [edit] Template parameters

T | - | a type to check

### [edit] Helper variable template

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

[edit]

## 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>

### [edit] 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> {};

### [edit] 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

### [edit] See also

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

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