std::is_void

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Defined in header `<type_traits>`

template< class T > struct is_void;		(C++11 feature)

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.

Inherited from std::integral_constant

Member constants


`value`	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)

Member types


Type	Definition

`value_type`	`bool`

`type`	std::integral_constant<bool, value>

[edit] Equivalent definition

template< class T >
struct is_void : std::integral_constant<
                     bool,
                     std::is_same<void, typename std::remove_cv<T>::type>::value
                  > {};

[edit] 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

[edit] See also

is_array (C++11)

checks if a type is an array type
(class template)

is_pointer (C++11)

checks if a type is a pointer type
(class template)

is_enum (C++11)

checks if a type is an enumeration 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 class type (but not union type)
(class template)

is_function (C++11)

checks if a type is a function type
(class template)

is_object (C++11)

checks if a type is object type
(class template)