Re: Unmatch variable

[Jon Paris <Jon.Paris@xxxxxxxxxxxxxx>]

Yes it is because the data definitions do not match.  And you were  
luck you were going long definition to short or you might not have  
spotted it so easily.

This is nothing to do with AS/400 - and for that matter nothing to do  
with COBOL really. It would happen with any version of COBOL and most  
any language.  The value that you see might be different on another  
platform - but likely not.

When a parameter is passed by reference (the default on i5/OS  
programs) only the address of the left-most byte is passed to the  
called routine and its interpretation of the data is what counts.   
Since the V is an implied decimal point (i.e. not really there) there  
is no alignment around the decimal place.  So when you pass in a 15  
digit field and then treat it as 13 digits - the last two digits  
"disappear" and the effect is as if you divided the value by 100.

You should _always_ make sure that the definitions of passed  
parameters match - or you will be doomed ot a life of debugging nasty  
problems.

Suppose for example you had done it the other way round and passed 13  
digits and treated it as 15.  When you set a value in the field you  
would be changing 15 bytes of storage  - but you only had 13 - so 2  
bytes of (potentially) another variable's storage just got corrupted.



Jon Paris

www.Partner400.com
www.SystemiDeveloper.com

On 5-May-08, at 6:01 AM, Riyadi, Agus wrote:

> Hi All,
>
> I don't now how AS/400 work, anybody can share with me ?
>
> I have a program let say program A and this program will call sub  
> program B,
>
> 01 LK-OPT  PIC X VALUE '1'.
> 01 LK-NBR  PIC S9(11)V9(4) VALUE ZERO.
> ....
>
> CALL PGM "B" USING LK-OPT LK-NBR.
>
>
> But in program B
>
> LINKAGE SECTION.
> 01 WK-OPT  PIC X VALUE '1'.
> 01 WK-NBR  PIC S9(9)V9(4) VALUE ZERO.
> ..
> ..
> MOVE 1 TO WK-NBR.
>
>
>
> My question is why LK-NBR become 100 ? Shoud be 1. Is this error  
> due to
> different variable definition in A and B ?
>
> rgds
> Agus R
>
>
> IMPORTANT NOTICE:
> The information in this email (and any attachments) is  
> confidential. If you are not the intended recipient, you must not  
> use or disseminate the information. If you have received this email  
> in error, please immediately notify me by "Reply" command and  
> permanently delete the original and any copies or printouts  
> thereof.  Although this email and any attachments are believed to  
> be free of any virus or other defect that might affect any computer  
> system into which it is received and opened, it is the  
> responsibility of the recipient to ensure that it is virus free and  
> no responsibility is accepted by American International Group, Inc.  
> or its subsidiaries or affiliates either jointly or severally, for  
> any loss or damage arising in any way from its use.
> --
> This is the COBOL Programming on the iSeries/AS400 (COBOL400-L)  
> mailing list
> To post a message email: COBOL400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/cobol400-l
> or email: COBOL400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/cobol400-l.