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std::is_object

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Revision as of 16:10, 2 November 2012 by P12bot (Talk | contribs)

 
 
 
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is_object
(C++11)
(C++11)
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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 class="t-dcl ">

<td >
template< class T >
struct is_object;
</td>

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

If T is an object type (that is, scalar, array, class, or union), provides the member constant value equal true. For any other type, value is false.

Contents

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 template]

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

#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

(C++11)
checks if a type is scalar type
(class template) [edit]
(C++11)
checks if a type is an array type
(class template) [edit]
(C++11)
checks if a type is an union type
(class template) [edit]
(C++11)
checks if a type is a class type (but not union type)
(class template) [edit]