policy.cpp

#include <iostream>  // std::cout / std::endl;                                                                                                        

using namespace std;

template <class Policy>
struct foo : Policy {
    int _a;

    foo(void) :
        Policy(this) {
        cout << "In foo ctor ..." << endl;
    }

    ~foo(void) {
    }

    void say_hello(void) const {
	cout << "Hello, world!" << endl;
    }
};

struct print_ctor_policy {
    print_ctor_policy(foo<print_ctor_policy> *p) {
        p->_a = 4;
        cout << p->_a << endl;
        p->say_hello();
    }
};

typedef foo<print_ctor_policy> foobar2_t;

int main() {
    cout << "test" << endl;

    foobar2_t omg;
    return 0;
}