[omniORB] Servant Forking

[Visscher, Bruce]

> I've developed a servant that provides an interface to a legacy
> FORTRAN simulation library to provide the capability of having
> multiple "instantiations" of the FORTRAN model.
> 
> I would like to be able to have some sort of daemon process similar to
> a Servant Activator that simply forks off a new process that runs a
> reference of my servant to be used by another client.  I need the
> servant to run as a new process because the legacy fortran model uses
> all global variables, retains its state, and cannot be re-initialized

Smells like OpenVMS.

> if a new client were to connect to it.  Once the client is finished
> with the servant, I want the servant to exit.
> 
> Does anyone have any experience

Yes.

> or suggestions doing anything 
> like this?

Don't.

;-)

Seriously, you might want to consider something like the CosEvents push/pull
model.  Either literally or as a model of how to solve this kind of problem.

I.e., the CosEvents/CosNotification servant becomes an agent that allows both end
points to be clients.  Even if you could change the memory model of the
legacy fortran code it might be committing other sins that cause it not to
play well as a multithreaded app.  Also, if you opt for the POA single threade
policy, I believe there will still be multiple threads in a process that has
omniORB servants (right Duncan?).

Again, it doesn't have to be CosEvents or CosNotification per se.  You could implement
something more application specific that follows the same basic idea as the push/pull
model.  I.e., a queuer/dequeuer.

I will leave it to up to you whether it is a good idea to fork a FORTRAN process
from a multithreaded C++ program in whatever environment you are in.

HTH,

Bruce Visscher

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