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__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

See also

<type_traits>
is_polymorphic Class