Re: Mysterious MCH3601 errors at V4R3M0

[boldt@xxxxxxxxxx]

Robin wrote:
>I have an ILE RPG program that is a registered exit program for one of the
>VI/400 exit points. It is called with 4 parameters. It is called MANY times
>every day. For the first 6 weeks after implementation it ran without
>failure. Since then it has experienced intermittent failures. Sometimes
>several times a day, sometimes only every 3-4 days. The failure is always
>the same. MCH3601. It always occurs on the first line of executable code.
>
>C                 MOVE   PARM3    DATASTRUCTURE
>
>PARM3 is unreferenced.
>
>Any good ideas would be greatly appreciated.

I assume you asked for a dump when you got the error?  Was PARM3
actually addressable?  In other words, was there really a parameter
passed?  That's the obvious interpretation.  If a parameter really
was passed on the call, then I have no idea what could be causing
the problem.

One more thing:  Have you determined what changed after the first
six weeks?  It could be some other program clobbering the stack
space of this program.  So, check the compile dates of other
programs and modules in the application.  As you know, these types
of bugs are the most challenging ones to solve.  The difficulty in
debugging these problems is that the bug is not normally where the
failure occurs.  In addition to checking for parameter mismatches
and mismatched import/export, also check how based variables are
used.

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com


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