Re: swap QTEMPs

[Gary Guthrie <GaryGuthrie@xxxxxxxx>]

Here's a good one regarding swapping pointers to QTEMP libraries. I
mentioned this to IBM so they may have done something about it, I
haven't checked.

Presume JOB1 and JOB2. Store JOB2's pointer to QTEMP in JOB1s PCO. Now
instead of swapping back, end the job. No problem right? Maybe NOT!!!

Another job starting up grabs the job structure that JOB1 used (for
performance reasons it hangs around as an eligible structure rather than
requiring the penalty of re-creation). This new job now has a pointer to
JOB2's QTEMP. Of course JOB2 may or not still be active or some other
new job might now have the QTEMP that JOB2 had... This could be really,
really, troublesome!!! Mix up a few QTEMP pointers and you could have
multiple jobs pointing to a single QTEMP. While this could be useful for
some things, it could be devastating in those cases where it was neither
intended nor detected!

Or how about storing a pointer to a permanent context (library) as a
pointer to QTEMP. I've done that before, too. That can be interesting.
It's handy for testing things done with another job's QTEMP objects. For
instance, you might have a job that's creating things in QTEMP and
things aren't going as expected. Create a permanent context, stuff it's
address in the PCO as if it's QTEMP, and let the job continue. Now from
another job you can perform all the normal OS/400 commands against the
job's QTEMP, because it's a permanent context with a normal library name
you can use in the commands.

Gary Guthrie
Technical Editor, NEWS/400 Magazine at http://www.news400.com
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