Re: re-entrant programs

[dockery@griffin.cuc.ab.ca (Sean Dockery)]

behrenss@Informatik.TU-Muenchen.DE (Soenke Behrens) wrote:

>Well, normally you use the term "reentrant" for routines (or algorithms).
>Of course, "routine collections" like an OS or a Toolbox or a Library
>can also be called reentrant, meaning that all their routines are
>reentrant.

Correct.  I did mean an application as something to which the
techniques are applied.

>Reentrance means that you may, for example, interrupt a routine, and,
>while it is interrupted, call it again (this can be nested ad infinitum,
>of course :)

Wouldn't this be as easy as having the initialization stage of the
routine save the old values of the variables in an internal buffer or
external stack, and restores the previous values when it reaches the
end of the routine?

I have previously implemented this inside some of my programs.  Oh,
well.  I guess it was bound to happen.  (Never mind: it's an inside
joke going around my programming group about me re-inventing the
wheel.)

>>	o What are some examples of re-entrant software?
>
>Unix kernals.

Actually, I have wrestled with the idea of programming a Unix
environment on the eight bit level, (I know: ick!) but have decided
that it would not be a reasonable course of action (simply because you
would require expanded RAM -- 128K is just not enough.)

>Soenke
>-- 
>More than silver, more than gold, I need   !    behrenss@informatik.
>electricity. I need it for my dreams.      !    tu-muenchen.de
>(RACTER)                                   !  FIDO: 2:246/13 Soenke Behrens

Thankyou for your reply; I wasn't sure if it was being posted
properly, or not.

sean
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