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From: herwin@gmu.edu (Harry Erwin)
Subject: Re: Safety of the Booch Ada 95 Components
Date: 1999/12/12
Date: 1999-12-13T01:17:22+00:00	[thread overview]
Message-ID: <1e2puqr.1ps7vpt1hpolsaN%herwin@gmu.edu> (raw)
In-Reply-To: 82up01$ddg$1@nnrp1.deja.com

Robert Dewar <robert_dewar@my-deja.com> wrote:

> In article <1e2ns7h.cx85ir1azwo9iN%herwin@gmu.edu>,
>   herwin@gmu.edu (Harry Erwin) wrote:
> > A deep copy of a pointer data structure may require more
> > memory than is available.
> 
> 
> A naive copy may have that characteristic, but it is always
> possible on modern machines to do such a copy with no additional
> storage. It just takes a bit of cleverness. Remember that every
> pointer has at least two spare bits.
> 

If what you're suggesting is sharing the underlying data, it's risky in
C++ since we have to manage the free store explicitly, rather than
relying on garbage collection. It is done that way for STL strings, but
there are some known problems, especially in a multithreaded
environment.

In any case, this discussion has been very educational. I now know where
in the documentation to go look for answers.

With thanks,
-- 
Harry Erwin, PhD, <http://mason.gmu.edu/~herwin>




  reply	other threads:[~1999-12-12  0:00 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-12-10  0:00 Safety of the Booch Ada 95 Components Harry Erwin
1999-12-10  0:00 ` Simon Wright
1999-12-12  0:00   ` Harry Erwin
1999-12-13  0:00     ` Simon Wright
1999-12-12  0:00   ` Simon Wright
1999-12-12  0:00     ` Matthew Heaney
1999-12-10  0:00 ` Matthew Heaney
1999-12-10  0:00   ` Hyman Rosen
1999-12-10  0:00     ` Harry Erwin
1999-12-10  0:00     ` Matthew Heaney
1999-12-11  0:00       ` Harry Erwin
1999-12-12  0:00         ` Robert Dewar
1999-12-12  0:00           ` Harry Erwin [this message]
1999-12-13  0:00           ` Kent Paul Dolan
1999-12-13  0:00             ` Simon Wright
1999-12-13  0:00             ` Ted Dennison
1999-12-13  0:00             ` Robert I. Eachus
1999-12-13  0:00       ` Hyman Rosen
1999-12-13  0:00         ` Robert I. Eachus
1999-12-14  0:00           ` Simon Wright
1999-12-15  0:00             ` Mats Weber
1999-12-17  0:00               ` Simon Wright
1999-12-15  0:00             ` Harry Erwin
1999-12-14  0:00         ` Matthew Heaney
1999-12-10  0:00   ` Harry Erwin
1999-12-12  0:00     ` Simon Wright
1999-12-12  0:00       ` Harry Erwin
1999-12-13  0:00         ` Simon Wright
1999-12-13  0:00 ` Tucker Taft
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