C++ virtual fn call during base ctor

#include <iostream>

struct Base {
    Base() { std::cout << "in Base ctor "; f(); }
    virtual void f() { std::cout << "Base::f() is called" << std::endl; }
    virtual ~Base() {}
};

struct Derived: public Base {
    Derived() : Base() { std::cout << "in Derived ctor "; f(); }
    virtual void f() { std::cout << "Derived::f() is called" << std::endl; }
    virtual ~Derived() {}
};

int main()
{
    Base *d = new Derived; // during construction: there is no polymorphism
    /*
     * Prints:
     * in Base ctor Base::f() is called
     * in Derived ctor Derived::f() is called
     */

    d->f(); // during normal member function call: polymorphism works
    /* Prints:
     * Derived::f() is called
     */
    delete d;
}