Greg Ewing: That's completely different from what I had in mind, which was:

(1) Keep a reference to the base object in the buffer object, and

(2) Use the buffer API to fetch a fresh pointer from the base object each time it's needed.

Is there some reason that still wouldn't be safe enough?

I don't know if this can help, but I have once created an object with this behaviour, you can get it at: http://s.keim.free.fr/mem/ (see the memslice module) From my experience, this solve all the problems caused by the buffer object. Sébastien Keim