inheritance and memory layout

[Anargyros L. Papadopoulos]

given:
class A {
// ...
};

class B : public class A {
// ...
}

void some_fun()
{
B b;
A *pa = &b;
B *pb = &b;

if ((void *)pa == (void *)pb) {
;
} else {
// is it possible ??
;
}
}

is it guarantee (from the standard), assuming single inheritance, that it is
impossible to reach the else statement in the above code?

 

[EventHelix.com]

With single inheritance, yes it is impossible to reach the else
statement.

The following article should help:

http://www.eventhelix.com/RealtimeMantra/basics/ComparingCPPAndCPerformance2.htm

Deepa

 

[rajkumar]

The said link just presents one way of implementing virtual functions.
I dont think standard says anything about how to implement virtual
functions.

The OP had asked in case of singled inheritance if else branch can be
true.

I think it can be if the user overloads & operator for B and does
something crazy

raj