🚀 go-pugleaf

jimad@microsoft.com (Jim Adcock) writes:
|class A {};
|
|class B : public A
|{
|public:
|	A a;
|};
|
|main()
|{
|	B b;
|	A* p1; 
|	A* p2;
|
|	p1 = &b;
|	p2 = &(b.a);
|
|	if (p1 == p2)
|		printf("equal %lX %lX\n", (long)p1, (long)p2);
|	else
|		printf("unequal %lX %LX\n", (long)p1, (long)p2);
|
|	return 0;
|}

ARM p74:  "Two pointers to the same object compare equal".
ARM p163: "An object of a class consists of a (possibly empty) sequence of 
	   members".

I don't know if ARM defines what "same object" means.
But, it seems to me a member is a different (i.e. not the same) object than
the "enclosing object".  

E.g. using the example above, 'b' is not the same object as 'b.a'.

Therefore, according to ARM p74-75, the pointer comparison in the example
above 'p1 == p2' (in effect '((A*) &b) == &b.a') is implementation dependent.

Atleast according to my reading of the ARM as it stands today...