std::is_void

 

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is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)
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is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)
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integral_constant (C++11)

 

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

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 [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)

Member types

Type	Definition
value_type	bool
type	std::integral_constant<bool, value>

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

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)