std::is_void

template< class T >
struct is_void;

Checks whether T is a void type. Provides the member constant value that is equal to true, if T is the type void, const void, volatile void, or const volatile void. Otherwise, value is equal to false.

Template parameters

Helper variable template

template< class T >
inline constexpr bool is_void_v = is_void<T>::value;

Possible implementation

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

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';
}

true
false

See also