RE: Function Opinion

[Joel Cochran <jrc@xxxxxxxxxx>]

Ummmm...

On Wed, 2003-10-15 at 15:52, Johnson, Duane wrote:
> Rick,
> 
> If you bind by module, then the program will need to be re-created any time
> one of the modules is changed.  

UPDPGM - you do NOT have to recreate the program because of a module
change.

> When you create and bind by service program,
> all that is needed is to recreate the service program, and the main program
> will pick it up, without having to be re-created.

UPDSRVPGM will update the service program and any bound programs as long
as the signature hasn't changed, you do not need to recreate the SRVPGM
ever time you change a module.

Even if you think you are avoiding Signatures, all service programs
retain a signature, so you are not.  Programs are compiled over those
signatures and then only the order number of the module/proceudre is
used in future calls.  Yes, by only having one procedure per module and
one module per service program you are "avoiding" the signature issue,
but you are not "escaping" it simply because you could make fundamental
changes to the procedure and the program would never know.

Here is an excercise for you: change one of your procedures that has say
a 50A parameter and make it 1024A.  Recreate your service program or
whatever you think you chould do.  Now put that baby into debug and look
at the contents of that parameter.  Should be very enlightening, but
don't forget, you didn't have to do anything to the program!

To be fair, using UPDSRVPGM will also not fix this issue: changing an
interface can have alarming results if you do not recompile the programs
that call the procedure.

I wrote about this some in my recent article at MidrangeServer.com:
http://www.midrangeserver.com/mpo/mpo092503-story02.html

Naturally there are ways around these problems, but I find avoiding them
the best answer.

Joel
http://www.rpgnext.com