void f(int∗ pi)
{
    void∗ pv = pi; // ok: implicit conversion of int* to void*
    ∗pv; //error : can’t dereference void*
    ++pv; //error : can’t increment void* (the size of the object pointed to is unknown)
    int∗ pi2 = static_cast<int∗>(pv); //explicit conversion back to int*
    double∗ pd1 = pv; // error
    double∗ pd2 = pi; // error
    double∗ pd3 = static_cast<double∗>(pv); // unsafe (§11.5.2)
}