C++ changes

[Roger H. <rog...@mi...>]

This is how I propose to start the changes to the instance data.

I will not be able to do everything in one editing session so to try
to maintain consistency in the CVS code I will have to work up the
class hierarchy one class at a time until all the leaf classes are
complete.

To do this I will change the instanceSize parameter of 
E3ClassTree_RegisterClass
to be TQ3Int32 instead of TQ3Uns32. The internals of the ClassTree 
routines will
then be changed so that they recognise a negative parameter as  being 
minus
the size of the class AND ALL ITS PARENTS including OpaqueTQ3Object.
This code will not need to handle the case of a child being negative 
and the
parent positive, only the other way around or both the same sign.

I can then change each class in turn by modifying the instance data to 
inherit
from its base class and add a minus sign before the sizeof in the 
class's call
to E3ClassTree_RegisterClass.

When all classes have been done we can take out the old code and take 
the
abs of the parameter and take out the minus signs as and when 
convenient.

Unless of course anyone has any objections or any better ideas.

Roger.