Re: CAT bug in ILE RPG

[Michael Calabro/commsoft<mcalabro@xxxxxxxxxxxx>]

Majobo@aol.com on 11/12/98 10:56:44 PM
Please respond to MIDRANGE-L@midrange.com
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Subject:        Re:  CAT bug in ILE RPG


>>Has anyone else run across bugs with the CAT operation code in RPG IV? 
>>Using CAT in some situations gives us unpredictable results, such as 
fields 
>>being concatenated in the wrong order.  (However, if instead we use EVAL 
>>and the plus sign on these same fields to concatenate them, the program 
>>works fine!)
>>
>> field1  CAT  field2:0   resultfld
>>          CAT  field3:0   resultfld
>>             .
>>             .
>>             .
>>          CAT  field9:0   resultfld
>>
>>The above does not work!! 
>>
>>But the following does work (we use %trimr because all 9 fields have 
>>trailing blanks):
>>
>>         EVAL     resultfld=%trimr(field1)+%trimr(field2)+ ...
>>+%trimr(field9)
>>
>Each of the nine fields that I am concatenating is a 4-byte character 
>string containing zero, one, or two numeric characters left-justified, 
>and then padded on the right with blanks.  The result field is a 
>16-character blank field.
>(It just so happens that the 3rd and 9th fields are always blanks.)
>In this example, in the interest of simplication, I have represented the
>numeric contents of the 9 fields with uppercase alphabetic characters, 
>and represented the blanks with lowercase "b"s.
>
>Abbb  CDbb   bbbb   EFbb   GHbb   JKbb   LMbb   NPbb   bbbb
>
>Per this example, the result field will always contain the following:
>
>ACDbbGHJKLMNPEFG

I have some converted code that uses lots of CATs so I was interested in 
this. 
When I run this example, my results turn out properly.  I've never had 
operations like 
this go "out of order".   Just to satisfy my curiosity, I recompiled my 
code at OPTIMIZE(*FULL)
and tried again: worked fine.  We're at V4R3, ptf level 98279.  This is 
clearly an example (i.e.
not your production code.)  Are you certain that the fields in your 
production code are being
CATted in the order you think?  Did the compile fail, and your object code 
doesn't match the
source you're looking at?  Dumb questions, but I've only found one compiler 
bug in 20 years.
I always think of the code having a problem before I think of the compiler 
having a problem...

Buck Calabro
Commsoft, Albany, NY
mailto:mcalabro@commsoft.net
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