🚀 go-pugleaf

In article <1993Jan7.025948.23000@lucid.com> jss@lucid.com (Jerry Schwarz) writes:
>	struct X { int i ; } ;
>	struct D : public X {
>		X xInD ;
>	} ;
>
	This example is not contentious. But:

	struct X { virtual int f()=0; };

	struct Y : public X { int i; int f(){return i;} };

	struct D : public X {
		Y y;
		int j;
		int f(){return j;}
	};

Now this example IS contentious. For an implementation not using
vtble pointers, the abstract class X might occupy 0 bytes.

Then:

	D d;
	d.i=1;
	d.j=2;
	
	X* p1=&d; // base subobject
	X* p2=&d.y; // included object base subobject
	p1==p2; // OH!
	cout<<"1=="<<p1->f();
	cout<<"2=="<<p2->f();

and I dont see how such an implementation could actually work
UNLESS at least the language require that abstract base
subobjects occupy at least one byte.

I dont believe this is required by the ARM, clearly it should be.

-- 
;----------------------------------------------------------------------
        JOHN (MAX) SKALLER,         maxtal@extro.ucc.su.oz.au
	Maxtal Pty Ltd, 6 MacKay St ASHFIELD, NSW 2131, AUSTRALIA
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