Open Source discussion on error handling was: RPGIII/RPG400 ERROR MONITORING

[Buck Calabro <buck.calabro@xxxxxxxxxxxxxxxxx>]

Oludare wrote:

>How do one monitor ERROR MESSAGES within an RPG 
>progam?  e.g. If program stratus is 00907= decimal-data 
>error in field.  How do one continue processing and 
>ignoring the message.

Leslie's link to the *PSSR chapter of the RPG manual is a great place to
start looking!  After you've viewed the chapter on error handling, you'll be
ready to deal with some of the practical issues that surround the use of
*PSSR to trap errors.  In fact, this is probably a really good place to
start an "open source" discussion on the merits of the various ways to trap
and handle errors within RPG programs.

You specifically asked about error handling in RPG III; alas my "boiler
plate example" is in RPG IV.  It doesn't really matter because it is a
simple conversion from RPG III.  I'll post it here and invite active
discussion on the pros and cons of why this code came about and how to make
it better.  When we're all done, perhaps we'll have an open source routine
that Leslie can post on his site.  If there's no discussion, I guess we'll
know why Open Source RPG doesn't work...

     H Debug

      * Sample code to demonstrate use of *PSSR directing
      * traffic after an error occurs

      * Global declarations
     D ErrFlag         S              1    Inz('N')
     D ErrAction       S              6    Inz('*DETC ')
     D CurrRoutine     S             10    Inz

      * Test numbers
     D POSITIVE        S              5S 0 Inz(15)
     D NEGATIVE        S              5S 0 Inz(-15)
     D ZERO            S              5S 0 Inz(0)
     D PI              S             10S 9 Inz(3.141592654)
     D Result          S              3S 0 Inz(0)

      * Routine names describe where we are in the program
      * When an error occurs, we can steer ourselves
      * back to the appropriate place in the program
     D RTNADD          S             10    Inz('Add       ')
     D RTNSUB          S             10    Inz('Sub       ')
     D RTNMUL          S             10    Inz('Mul       ')
     D RTNDIV          S             10    Inz('Div       ')

     D                SDS
     D  PGNAME           *PROC
     D  STATUS           *STATUS
     D  TMNAME               244    253
     D  USRNAM               254    263
     D  JOBNBR               264    269  0

      * Mainline.  This is just simple code to demonstrate
      * how we can direct traffic after an error occurs
      * The *PSSR traps the error, gets control and then
      * returns to this point in the program.
      *    *DETC         Tag

      * Did an error occur?  If so, recover!
      * For example's sake, only test/recover from an error
      * in the division routine
      * A huge disadvantage to this style of error recovery is that
      * the "error handler" needs to know the internals of the
      * failing routine.  Here, we're setting Result to 0: we need
      * to know that the RTNDIV routine is doing a divide, that it
      * returns Result and that the "proper" recovery is to set
      * Result to 0.

     C                   If        ErrFlag='Y'
     C                   Eval      ErrFlag='N'

     C                   Select

     C                   When      CurrRoutine = RTNDIV
     C                   Eval      Result=0
     C                   GoTo      PastDiv

     C                   Other
     C                   Dump

     C                   EndSl
     C                   EndIf

      * Program processing occurs here
     C     Add           Tag
     C                   Eval      CurrRoutine=RTNADD
     C                   Eval      Result=ZERO+1

     C     Sub           Tag
     C                   Eval      CurrRoutine=RTNSUB
     C                   Eval      Result=ZERO-1

     C     Mul           Tag
     C                   Eval      CurrRoutine=RTNMUL
     C                   Eval      Result=ZERO*1

     C     Div           Tag
     C                   Eval      CurrRoutine=RTNDIV
     C                   Eval      Result=PI/ZERO
     C     PastDiv       Tag

     C                   Eval      *InLR=*On

      * An error has occurred
      * Set the "Error is happening" flag and return to the mainline
      * We could also take recovery actions here as well as setting the flag
      * but that would entail duplicating the "traffic cop" code somewhat.
     C     *PSSR         BegSR
     C                   Eval      ErrFlag='Y'
     C                   EndSR     ErrAction

Buck
(thinking positive instead of ranting for a change)
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