Call a derived member function from parent class

Question

I need to call B::f() in the thread member function. What I get is "pure virtual method called". How can I do this?

I assume all this happens because of &A::thread_f in the A initializer list where I explicitly name a scope.

class A {
protected:
    std::thread _thread;

    A() : _thread(&A::thread_f, this) { }

    ~A() { 
        _thread.join();
    }

    virtual void f() = 0;

    void thread_f() {
        f();
    }
};

class B : public A {
protected:
    void f() override {
        std::cout << "B::f()" << std::endl;
    }
};

Answer 1

as @Evg says, by starting a thread,A ctor call member function f of B before constructing B.

The solution is to start thread after B is constructed.

#include<iostream>
#include<vector>
#include <stdlib.h>
#include <thread>

using namespace std;
class A {
public:
    ~A() {
        _thread.join();
    }
    void start()
    {
        _thread = std::thread(&A::thread_f, this);
    }
protected:
    std::thread _thread;
    A()
    {
    }

    virtual void f() = 0;
    void thread_f() {
        f();
    }
};

    class B : public A {
    protected:
        void f() override
        {
            std::cout << "B::f()" << std::endl;
        }
    };

void main() {
    A *pA=new B;
    pA->start();
    delete pA;
}