Re: Communication programs..

Your ICFF is defined as a WORKSTN file.  And it can be in RPG with no
problems.  In fact, I recommend it.

After you do the CRTICFF, then do an ADDICFDEVE PGMDEV(RQSDEV)
RMTLOCNAME(*REQUESTOR)

Then before you do anything with the file, you need to do an Aquire.
Rpg to do this is: 'PGMDEV'  ACQ  MYICFFILE.  That is the "old" RPG.
There is an equivalent in ILE/RPG, I just don't know what it is.

You can then start reading and writing, with all of the correct
keywords. (be carefull  here!).

For examples, look at the Client Access toolkit.  If you can find
nothing there, look in the PC Support documentation.  All of this is
for doing APPC between an AS/400 and PC...but the logic and everything
is the same for AS/400 to AS/400.

You will need to be careful about what status your conversation is in.
E.g.: Who is reading and who is writing and when & how to turn the
conversation around so the side that was reading is now sending.

Regarding Data Queues, they really have nothing to do with APPC
programs.  Though many times, APPC programs will use Data Queues, they
are pretty much unrelated.

Depending on what you are doing, there is a "Data Queue" interface with
Client Access.  When you use this, you do not use APPC.  You accomplish
all of your sending & receiving with the target system via Data Queues.
It works pretty good if you are dealing with small amounts of data and
do not have complex "conversation logic".  E.g.: PC sends a record to
the /400 saying "print this invoice".

By the way, what are you trying to do?  Once you have figured out APPC,
it is not hard at all.  However, the "figuring" out process is not for
the faint of heart.

Another approach to think about might be TCP/IP and Sockets. But this
is probably done better with a combination of C and RPG rather than
pure RPG.  It is possible with pure RPG (so I've heard), but not
pretty.  BTW, I think there are some 3rd party middle ware products
that greatly simplify this for the RPG programmer.

It just depends on what you are trying to do and what you are doing it
with.  Also, is this for in-house or a product?  For in-house the CA
Data Queue approach might work well.  For a product, I'd steer clear of
it.

After doing APPC for many years, I've moved to Sockets.  Much better
and there is no Client Access involved.

Regards,
Bob Crothers

-----Original Message-----
From: Sudha Ramanujan <sramanujan@sungardfutures.com>
To: MIDRANGE-L@midrange.com <MIDRANGE-L@midrange.com>
Date: Wednesday, November 25, 1998 12:14 PM
Subject: Communication programs..


>Hi all,
>
>How do ICFF programs work?  Does it have to be a C program or could I
write
>this in RPG too (Is there an example somewhere in the Redbooks that I
could
>use)?  I tried to write a program in RPG and had problems in F spec
with
>this file.  I could not define this as workstation and use the write
Evoke
>record.  When I defined this as a Special file, the program compiled
but had
>problems while running. Could someone throw some light on this please?
Here
>is what I have for each sending & receiving end :
>
>
>- An ICFF file.
>- A workstation file for Menus & other options.
>- A CL to overlay the Pgm Dev Entry OVRICFDEVE and call to the (RPG)
>program.
>- RPG to actually receive/write the ICFF & workstation file.
>
>Again, should dataques be used with ICFF files?   How will they
improve the
>performance?
>
>Any and all help would be appreciated.
>
>Thanks,
>Sudha
>
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