c++ implementation of access specifiers

Question

From what I understand, non-static data members in a c++ class are packed into a C-style struct. Ignoring virtual functions and inheritance for the sake of simplifying this discussion, how are access-specifiers enforced in such a scheme ?

say a class:

class Object
    {
public:
    int i1;
    int i2;
private:
    char i3;
    int i4;
    };

translates to:

struct { 
  int i1;
  int i2;
  char i3;
  int i4;
}

How does c++ ensure that private members i3 and i4 can not be accessed outside the class but i1 and i2 can be?

Answer 1

C++ has (some) safe guards to protect against Murphy, not Machiavelli.

What this means is that the const, volatile and access-qualifiers are checked at compilation time, but even then can be bypassed (with a variety of tricks).

So... C++ does not require implementing a protection scheme. If the program compiled, it is deemed correct (wrt those qualifiers) and will be executed without runtime checks.