is_void Class
Tests whether the type is void.
Syntax
template <class T>
struct is_void;
Parameters
T
The type to query.
Remarks
An instance of the type predicate holds true if the type T is void or a cv-qualified form of void, otherwise it holds false.
Example
// std__type_traits__is_void.cpp
// compile with: /EHsc
#include <type_traits>
#include <iostream>
struct trivial
{
int val;
};
int main()
{
std::cout << "is_void<trivial> == " << std::boolalpha
<< std::is_void<trivial>::value << std::endl;
std::cout << "is_void<void()> == " << std::boolalpha
<< std::is_void<void()>::value << std::endl;
std::cout << "is_void<void> == " << std::boolalpha
<< std::is_void<void>::value << std::endl;
return (0);
}
is_void<trivial> == false
is_void<void()> == false
is_void<void> == true
Requirements
Header: <type_traits>
Namespace: std