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std::is_void

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Revision as of 15:50, 2 November 2012 by P12bot (Talk | contribs)

 
 
 
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is_void
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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_void;
</td>

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

If T is the type void, const void, volatile void, or const volatile void, 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 the type void (possibly cv-qualified) , 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_void : std::integral_constant<
                     bool,
                     std::is_same<void, typename std::remove_cv<T>::type>::value
                  > {};

Example

#include <iostream>
#include <type_traits>
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_void<void>::value << '\n';
    std::cout << std::is_void<int>::value << '\n';
}

Output:

true
false

See also

(C++11)
checks if a type is an array type
(class template) [edit]
checks if a type is a pointer type
(class template) [edit]
(C++11)
checks if a type is an enumeration 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]
checks if a type is a function type
(class template) [edit]
(C++11)
checks if a type is object type
(class template) [edit]