function test()
{
   beep();
}

function calling_func(function* f)
{
   ... // not sure what to write here cause f; or f(); wont work
}

calling_func(test);

void foo(void *f)
{
    void fp(); // The signature should obviously match with the one of the function

    fp = f; // Note that you won't get any help from the static typesystem here, so know what you are doing!
    fp();
}

foo(test); // Or just pass beep directly here

void test()
{
    beep();
}

function calling_func(void* p)
{
    void f();
    f = p;
    f();
}

function foo()
{
    return 1337; // Always return values from functions.
    // When using "function" returns a var, when using int return an int etc.
}

void bar()
{
    return; // Don't return a value when using void.
}