Re: question: DLD write and debug

[Paul Kienzle]

On Apr 20, 2004, at 4:42 AM, Eric Chassande-Mottin wrote:

> > Yes.  It makes it more difficult for functions to be reentrant,
> > and it will make multithreading even harder to do.
> >
> > I ran into reentrancy problems today with fsolve, but I
> > don't see multithreading being an issue for the foreseeable
> > future.
>
> hi Paul,
>
> thanks for your answer.
>
> I didn't know what 'reentrant' means. I went on wikipedia :
>
> `` A computer program or routine is described as reentrant if it is
> designed such that a single copy of the program's instructions in 
> memory
> can be shared by multiple users or separate processes.  The key to the
> design of a reentrant program is to ensure that no portion of the 
> program
> code is modified by the different users/processes, and that 
> process-unique
> information (such as local variables) is kept in a separate area of 
> memory
> that is distinct for each user or process.''
>
> since a DLD is accessed by only one Octave, why do you want it to be
> reentrant?

fsolve cannot be called from within fsolve because "unique information
(such as local variables) [is not] kept in a separate area of memory 
that
is distinct for each [call to fsolve]."  That is, it uses static 
variables so it is
not reentrant.

Paul Kienzle
address@hidden



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