is_abstract Class
The latest version of this topic can be found at is_abstract Class.
Tests if type is abstract class.
Syntax
template <class Ty>
struct is_abstract;
Parameters
Ty
The type to query.
Remarks
An instance of the type predicate holds true if the type Ty is a class that has at least one pure virtual function, otherwise it holds false.
Example
// std_tr1__type_traits__is_abstract.cpp
// compile with: /EHsc
#include <type_traits>
#include <iostream>
struct trivial
{
int val;
};
struct abstract
{
virtual int val() = 0;
};
int main()
{
std::cout << "is_abstract<trivial> == " << std::boolalpha
<< std::is_abstract<trivial>::value << std::endl;
std::cout << "is_abstract<abstract> == " << std::boolalpha
<< std::is_abstract<abstract>::value << std::endl;
return (0);
}
is_abstract<trivial> == false
is_abstract<abstract> == true
Requirements
Header: <type_traits>
Namespace: std