Re: Tool class (Long... *real* Long)

[Theodore C. Belding]

Hi Ken-

At 1:17 AM -0500 3/20/97, Ken Cline wrote:>Problems:
>   (1) How does agent B assure that object X's data isn't
>       altered while B is using X?

Sounds like a job for a mutual exclusion (mutex) semaphore.  See any decent
OS textbook, e.g., Silberschatz, A., and P. B. Galvin. (1994). Operating
Systems Concepts, 4th ed. Addison-Wesley. p. 177

>   (2) Who, agent A or agent B or ???,  has the
>       responsibility for dropping the shared object X?

Sounds like a classic place to use reference counting or reference-counted
smart pointers.  See:
Meyers, S. (1996). More Effective C++. Addison-Wesley. pp. 183-213.
or
Barton, J. J., and L. R. Nackman (1994). Scientific and Engineering C++.
Addison-Wesley. p. 425

(Both are C++-specific, but the concept is general.  Maybe someone else can
suggest a more general reference.)  Of course, you could also just use
garbage collection, if it is available.

Hope that helps.
-Ted

--
Ted Belding                      <mailto:address@hidden>
University of Michigan Program for the Study of Complex Systems
<http://www-personal.engin.umich.edu/~streak/>