Re: Variable corruption

["Peter Dow" <pcdow@xxxxxxxxx>]

Hi Loyd,

Without seeing all the details, it smells like you've got some parameters to
QWCCVTDT defined with the wrong size or something. For example, if the API
is expecting a 10-character field and you pass it a 6-character field, it
will change the 4 characters immediately following the 6-character field. If
these 4 happened to be nextpos, results are unpredictable.

That's just a guess.

Peter Dow
Dow Software Services, Inc.
909 425-0194 voice/fax


----- Original Message -----
From: Goodbar, Loyd (AFS-Water Valley) <LGoodbar@afs.bwauto.com>
To: <midrange-l@midrange.com>
Sent: Friday, October 01, 1999 8:03 AM
Subject: Variable corruption


> Has anyone experienced variable corruption while using APIs in an RPG/IV
> program (non-ILE)?
>
> I wrote a progam to process save files (retrieve info and display).
> Everything worked fine until I started using the QWCCVTDT (Convert date
and
> time format) API.
>
> Here's a quick sample:
> - - - - -
>
> d nextpos 9b 0 inz
> c eval nextpos = offstart + 1
> c do numentries
>  * Receive entry
> c call 'QUSRTVUS'
> c parms .........
>  * Process if save file
> c if extatr = 'SAVF'
>  * Convert creation date
> c call 'QWCCVTDT'
> c parms........
>  * Display
> .....
> c endif
> c eval nextpos = nextpos + sizeent
> c enddo
>
> - - - - -
>
> Before using the QWCCVTDT API, nextpos would increment by 172 (the length
of
> the OBJL0300 return list). After inserting the API, nextpos would become
> corrupted after the QWCCVTDT API was called.
>
> For example, nextpos would increment from 1196 to 1368 (not real numbers).
> After calling the QWCCVTDT, nextpos was -252513633.
>
> Using this code fixed the problem:
>
> - - - - -
>
> d mynextpos 9b 0 inz               (NEW)
> d nextpos 9b 0 inz
> c eval nextpos = offstart + 1
> c do numentries
>  * Receive entry
> c call 'QUSRTVUS'
> c parms .........
> c eval mynextpos = nextpos         (NEW)
>  * Process if save file
> c if extatr = 'SAVF'
>  * Convert creation date
> c call 'QWCCVTDT'
> c parms........
>  * Display
> .....
> c endif
> c eval nextpos = mynextpos       (NEW)
> c eval nextpos = nextpos + sizeent
> c enddo
>
> - - - - -
>
> nextpos is used with the QUSRTVUS API, but not with the QWCCVTDT API.
> Has anyone had experience with the variable corruption I'm experiencing?
It
> was easy to work around, but this does concern me.
>
> Thanks!
>
> --
> Loyd Goodbar
> Programmer/Analyst
> Borg-Warner Automotive, AFS, Water Valley
>
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