Re: Structure mapping using reinterpret_cast.

By extension, if that is true, the following code should be
guaranteed to work :

     #include <iostream>

     // Base class containing the data.
     class A
     {
     public:
         A( int val = 0 ) : val_(val) { }

     protected:
         int get_value( ) const
         { return val_; }

     private:
          int val_;
     };

     // Interface class that uses A's data.
     class B : public A
     {
     public:
         int function( ) const
         { return get_value() / 2; }
     };

     // Another interface class that uses A's data.
     class C : public A
     {
     public:
         int function( ) const
         { return get_value() * 2; }
     };

     int main( )
     {
         A *a = new A(12);

         B *b = reinterpret_cast<B *>(a);
         std::cout << b->function() << "\n";

         C *c = reinterpret_cast<C *>(a);
         std::cout << c->function() << "\n";

         delete a;
     }

If this isn't the case, could anyone quote the entry in the
standard that states this code yields undefined behavior ?