Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!kent
From: kent@swrinde.nde.swri.edu (Kent D. Polk)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Inter process communication
Message-ID: <1808@swrinde.nde.swri.edu>
Date: 11 Mar 91 18:41:51 GMT
References: <19579@cbmvax.commodore.com> <10708@dog.ee.lbl.gov> <11854@pasteur.Berkeley.EDU>
Sender: news@swrinde.nde.swri.edu
Organization: Southwest Research Institute, San Antonio, Texas
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In article <11854@pasteur.Berkeley.EDU> navas@cory.Berkeley.EDU writes:
>In article <> jnmoyne@lbl.gov (Jean-Noel MOYNE) writes:
>
>>       But there is another solution: Pete Goodeve has written a package 
>>called IPC for "Inter Process Communication" (how did you guess ? (-:). 
>>
>
>PPIPC (Pete & Peter's IPC) is very good for server-client modelled
>communications, can get hairy for one-to-many broadcasts, and still doesn't
>solve the disappearing ReplyMsg port, but I use it *always* instead of the
>regular calls, because of the added protection they provide.
>At least one other person on the net has used it in his scientific
>application, but I'll let him discuss what he thinks about it...

...Um...
...Me?..

At the risk of taxing the patience of those who keep seeing me talk
about this, please forgive.

I use PPIPC in server/client and peer/peer relationships in my data
acq. system. I mainly use it to get around the "disappearing ReplyMsg
port" problem in conjunction with a semaphore-controlled message-port
list of peer/peer tasks. I haven't noticed a problem with this using
PPIPC under 2.0 in the client/server mode, as my mechanisms pretty much
prevent this from happening (I think).

However, it can happen during the peer/peer modes, and so use the
semaphore list & PPIPC facilities to determine what the replyport is.
The semaphore list usually gives me an available replyport since the
semaphore is obtained while a peer task is shutting down. (I control
startup/shutdown of tasks to explicitly control this).  In the case
when I have lost the peer msgport, I then again consult the semaphore
list to determine the next peer to send the message to. This mechanism
allows my data acq. system to handle inserting/deleting filter tasks
while messages/data are running through the system.

As you can see, I don't have as much of a problem since I attempt to
control the situations which would lead to the problems you guys are
discussing. I also use very few of the fancy PPIPC capabilities right
now, but am working on it. :^)

Kent Polk: Southwest Research Institute (512) 522-2882
Internet : kent@swrinde.nde.swri.edu
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