C++, equivalence between pointer-to-functions and pointer-to-member-functions?

boost::function f<(void)(MyObject*, int, int)> = &MyObject::method_that_takes_two_ints;

void (MyObject::*f)( int, int ) = &MyObject::method_that_takes_two_ints;

void (MyObject::*f)( int, int ) = &MyObject::method_that_takes_two_ints;

MyObject o; (o.*f)(1, 2);

int main() {
    typedef void fun() const;
    fun MyObject::*mem_function_ptr =
        &MyObject::const_method_that_takes_two_ints;
}

void foo() { cout << "hello"; }
int main() {
    typedef void fun();
    fun * f = &foo;
}

struct A {
    operator int() const { return 0; }
};

int main() {
    A a;
    int i = a; // implicit conversion using the conversion function
}