Re: Optional parameters in CLLE

Thanks all for the info. The simplest fix for my issue is to front-end it with a CMD object. Eliminates all the hassles and covers me for the extra long parm that is an option.

In the combination of tests I did, the omitted parm was always hex zero's. I have to admit I was (pleasantly) surprised at the consistency. But.. not enough to trust running hundreds of times per day in production.

Roger Harman
COMMON Certified Application Developer - ILE RPG on IBM i on Power

 
 





From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxx> on behalf of Jon Paris <jon.paris@xxxxxxxxxxxxxx>
Sent: Thursday, March 16, 2017 8:29 AM
To: Midrange-L Midrange-l
Subject: Re: Optional parameters in CLLE
 
The biggest danger with MONMSG is that parameters are passed differently between programs and procedures. Today the routine is written to only handle programs - but what if down the road somebody decides to use it as a bound procedure?

For those readers who don't appreciate the difference I wrote a pice for ITJ recently which you can find here:

https://www.itjungle.com/2017/02/20/guru-parameter-passing-fundamentals-programs-versus-procedures/

https://e5ce463uma323hyvrr4xumqs-wpengine.netdna-ssl.com/wp-content/uploads/2016/12/itj-logo.gif

Guru: Parameter Passing Fundamentals Of Programs Versus Procedures - IT Jungle
www.itjungle.com
In my earlier tip, Fundamentals: Parameter Passing, I discussed the basics of parameter passing and the importance of ensuring that parameter lengths and data types match those expected by the called routine. In this tip I want to go one step further and discuss differences between passing parameters to programs and to procedures. Let’s start


It uses RPG examples but the principals are the same.

Oh - and I'm not sure and don't have time to check - but not all languages pass the minimal parameter descriptors that I think the CEE routines depend upon. Others probably know and hopefully will comment.


Jon Paris

www.partner400.com


Partner400 - Your partner in iSeries education
www.partner400.com
If you are looking for the very best in IBM i* Education, Consulting and Mentoring services you have come to the right place! We are dedicated to helping our ...

www.SystemiDeveloper.com

On Mar 16, 2017, at 9:49 AM, dlclark@xxxxxxxxxxxxxxxx wrote:

"MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx> wrote on 03/15/2017
07:33:45 PM:

I have a couple of processes where I'd like to have one or two optional

parms.

In the past, I've just tried using them in a CHGVAR and monitor for

MCH3601.

But...  I'm wondering if %address() can be used instead.  I think it
would be cleaner.  In my testing, I've seen hex zeros for the %
address of a non-passed parm.  That seems to indicate a *NULL will
be returned.  Since it's consistent and not a garbage address, I
would think I could count on that logoc.

        As hinted at but may not have been made completely clear, %ADDR()
will work in *OMIT situations but will not work in *NOPASS situations. I'm
very content with depending upon MONMSG but since CLLE doesn't have a
built-in function for %PARMS() then others probably prefer to call the LE
routines.

Sincerely,

Dave Clark
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