Re: *PSSR subroutine and the call stack

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Paul,

Aaaarrrrggghjhhh, fffffffff....!  I should know better.  I wrote it without the 
manual handy.  
I forgot about RPG allowing resulting indicators on numeric operations (awful 
technique, up 
there with field indicators) -- although I shouldn't have, after all why are 
they also called 
+, -, and Z!  I picked DIV by zero because it is such an obvious error.

Alright.  Second bash.  The principle discussed is correct; the specific 
example is incorrect.  
Errors on arithmetic operations will pass control to the *PSSR if it exists.  
As you pointed 
out other operations support the technique I was illustrating:
        o File operations other than EXCEPT
        o ACQ, ADDDUR, CALL, CALLB, CHECK, CHECKR, COMMIT, DSPLY, EXTRCT, FREE, 
IN, OCCUR, 
OUT, REL, RESET, ROLBK, SCAN, SUBDUR, SUBST, TEST(D/T/Z), UNLOCK, XLATE

Have I redeemed myself?

Two children at Sunday School.  One says to the other, "We're studying 
Revelations.  What are 
you up to?"  The other one says. "Oh, our teacher says we're past redemption."

Regards,
Simon Coulter.

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//--- forwarded letter -------------------------------------------------------
> X-Mailer: Mozilla 4.51 [en] (Win95; I)
> Date: Sun, 09 May 99 22:25:50 +0100
> From: "Paul Tuohy" <tuohyp@ibm.net>
> To: MIDRANGE-L@midrange.com
> Reply-To: MIDRANGE-L@midrange.com
> Subject: Re: *PSSR subroutine and the call stack

> Simon Coulter wrote:
> 
> > Hello Albert,
> > <<< snip >>>
> >  For instance, a
> > divide by zero operation is an error.  If you code it as:
> >         C               DIV     0       RESULT
> > this is an unmonitored exception and the RPG error handler causes an 
>inquiry message to be
> > sent.  If you code it as:
> >         C               DIV     0       RESULT                  --99--
> > you are using indicator 99 in the LO column to monitor for exceptions on 
>the DIV 
operation.
> > You can of course use %ERROR in more recent dialects of RPG IV.  If you 
>code it as in the
> > first example but also have a *PSSR in the program then you are performing 
>a global 
exception
> > monitor (like MONMSG CPF0000 in CL).
> 
>   <<<<snip>>>
> 
> Simon, correct me if I am wrong (no machine or manual handy) but I think that 
>the LO 
indicator on
> a DIV operation will signify that the result of the divide is less then zero, 
>not that an 
error
> has occured. Where as some of the non-file operation codes can have an error 
>indicator 
defined
> (CALL, IN etc.), I think DIV is the exception. In ye oldie days of RPG, prior 
>to structured
> operation codes, the resulting indicators were used on arithmetic operations 
>to signify that 
the
> result was <, > or  = to zero.
> 
> Regards
> 
> Paul Tuohy.

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