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Date: Wed, 23 Jan 2002 16:12:11 -0500
From: Hyman Rosen <hyrosen@mail.com>
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Subject: Re: True faiths ( was Re: The true faith )
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Date: 2002-01-23T16:12:11-05:00
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Kenny Tilton wrote:
> Hyman Rosen wrote:
>>You don't get to redefine the problem so that your favorite technique
>>becomes the solution.
> 
> GC does not redefine the problem, it eliminates it. Which was the point.

It does no such thing. The original problem specified an object with
two subobjects which were owned by the parent and with a non-empty
base object. You must write assignment for this type so that the
destination acquires its own private copies of the subobjects of the
source, and such that if copying any subcomponent fails (with an
exception) you leave the destination object undamaged.

You do *not* get to hand-wave away the requirement of copying the
subobjects. Say, for example, they represent a pair of buffers. After
the copy is made, the source object and the destination object are
independent - when one writes into its buffers, the other must not
see any change to its own.