Conference bulova::decw_jan-89_to_nov-90

1388.0. "Applications screw up if LNM$FILE_DEV is modified" by HYDRA::COAR (Have you mutated yet to-day?) Wed Sep 06 1989 16:21

When I first started playing with DECwindows (V1, VMS V5.1), I noticed that
the application windows were always really barfucious.  They'd start out in the
upper left corner of the screen, sized really weirdly (like, �scopic), and the
menus would be funky in a big way.  Well, after playing games with my login
procedures, I discovered that this was all caused by my modifying LNM$FILE_DEV.

What my login did was create a logical name table, and insert it into the
LNM$FILE_DEV list in front of LNM$PROCESS (i.e., at the very beginning of the
list).  I find this puzzling and annoying, since LNM$FILE_DEV is available to
customers for modification and tailoring.

This was definitely an `it hurts when I do this' - `so, don't do that' sort of
problem, and I worked around it by NOT taking the above steps if I determined
I was a DECwindows client process.  However, I don't think that what I saw was
intended behaviour, nor desirable.

This situation has been QARed (number 3504 in the DECWINDOWS-IFT database).
I mention it here merely for the edification of others.

#ken	:-)}

Did you actually find all the tables that were in LNM$FILE_DEV and insert
your new table in them, or did you assume that it was composed of
process, job, group, and system tables and just create an LNM$FILE_DEV that
had process, yours, group, system?  If you did the latter, that is probably
the trouble, since you eliminated DECW$LOGICAL_NAMES, a new table added
by DW.  See SYS$MANAGER:DECW$LOGICALS.COM for how to add a table without
deleting old ones.

Burns

    Ah HAH!

    Except it isn't quite as you think; I was making that assumption and
    creating LNM$FILE_DEV in the PROCESS_DIRECTORY, not the SYSTEM_DIRECTORY.
    But you're quite correct; I (*I*!) have been found guilty of non-modular
    behaviour.  Ooh, that hurts!

    Even so, LNM$FILE_DEV is available for tailoring by customers.  Is the
    fact that this DECW$mumble table has been added to the `default'
    definition documented anywhere?  Particularly in the form of a caveat?

    #ken-who-doesn't-RTM-unless-he's-put-his-foot-in-it	    |-P}