Const prevents the procedure from changing the value directly. But it's not saying you can't change the global variable that was passed into the procedure.
As Darren said, passing a value by Const means that it's passing a pointer. So atrval_p isn't really changing at all. It's still pointing to the same spot in memory, it's just that you've changed what's in memory by changing a global variable.
Quick fix: use Value instead. I groan as I recommend that. Just be aware of the properties of Const and Value and you should be fine. (FYI: Value will pass the parameter as the data value, not as a pointer.)
Longer fix: get away from what you're doing with setting global variables from a procedure the best you can. Otherwise you may run into that issue again somewhere else (or not even realize you did it and cause a problem in production code).
-Kurt
-----Original Message-----
From: wdsci-l-bounces@xxxxxxxxxxxx [mailto:wdsci-l-bounces@xxxxxxxxxxxx] On Behalf Of darren@xxxxxxxxx
Sent: Thursday, February 20, 2014 8:21 AM
To: Rational Developer for IBM i / Websphere Development Studio Client for System i & iSeries
Subject: Re: [WDSCI-L] CONST parameter changed?
You might get better response in the RPG list. This list is more for RDi discussions.
I will say that atrval20 is probably defined as a global static variable in your program. It is then passed by reference using a pointer to WriteAttribute. Then you are resetting the global variable, which subprocedures have access to. I would say that this has always been possible, although CONST doesn't always pass the variable as a reference, so the behavior might seem sporadic.
From: "Colpaert, Peter" <Peter.Colpaert@xxxxxxxxxxx>
To: Rational Developer for IBM i / Websphere Development Studio
Client for System i & iSeries <wdsci-l@xxxxxxxxxxxx>
Date: 02/20/2014 08:14 AM
Subject: [WDSCI-L] CONST parameter changed?
Sent by: wdsci-l-bounces@xxxxxxxxxxxx
Hi group,
I encountered a strange issue today when coding a procedure.
In my main procedure, I call a subprocedure:
WriteAttribute(o_pdmnbr19:
o_vernbr19:
*blanks:
atride94:
atrval20);
In my WriteAttribute procedure, I have the following interface:
Dcl-proc WriteAttribute;
Dcl-pi *n;
pdmnbr_p like(pdmnbr20) const;
vernbr_p like(vernbr20) const;
colint_p like(colint53) const;
atride_p like(atride20) const;
atrval_p like(atrval20) const;
End-Pi;
At one point in the subprocedure, I do a reset of the record format containing - among other fields - ATRVAL20.
As soon as I do this Reset, the atrval_p field goes blank also.
Is this normal behaviour or am I doing something wrong?
I thought that the CONST keyword indicated that your parameter could not be changed...
Met vriendelijke groeten / Best regards,
Peter Colpaert
Software Engineer - PLM Development Team IT Operations Cluster Benelux, Philips IT
Philips Consumer Luminaires
Industrieterrein Satenrozen 11, 2550 Kontich, Belgium
Tel: (+32) 3/459 13 17
Email: Peter.Colpaert@xxxxxxxxxxx<mailto:Peter.Colpaert@xxxxxxxxxxx>
Working from home on Wednesdays
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