Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!mcsun!ukc!canon!smith
From: smith@canon.co.uk (Mark Smith)
Newsgroups: comp.windows.news
Subject: weird tNt behaviour?
Message-ID: <1990Aug21.144958.6645@canon.co.uk>
Date: 21 Aug 90 14:49:58 GMT
Distribution: comp
Organization: Canon Research Europe, Guildford, UK
Lines: 78

Well, at the risk of looking like a complete and utter prat, I throw
myself on the mercy of comp.windows.news in the hope of finding an
explanation for some very bizarre behaviour in OW 2.0.  Below is a
simple window class definition, followed by 4 lines which create a
window on the desktop:

------------------------------------------------------------------------

/TestFrame OpenLookBaseFrame

    dictbegin
    dictend

    classbegin

        /newinit
        {
            (newinit userdict:\n) printf
            userdict ==
            (\n\n) printf

            /newinit super send
        } def

        /destroy
        {
            (destroy userdict:\n) printf
            userdict ==
            (\n\n) printf

            /destroy super send
        } def

        /place
        {
            reshapefromuser
        } def

    classend
def

/win ClassCanvas [] framebuffer /new TestFrame send def
/place win send
/activate win send
/map win send

------------------------------------------------------------------------

If you start up a psh and stuff this into it, you should see
the current userdict shown in the psh when newinit is executed.
Next, position and size the window on the desktop as usual.
When you choose Quit from the window's frame menu, you'll see
the current userdict in the psh again when destroy is executed.
The window doesn't go away since /win in userdict has a reference
to it.  Now comes the weird part.  If you remove the last reference
by, for instance, typing "userdict /win undef" in the psh, the
destroy method gets called *again*, this time in an apparently
different context (userdict is empty).  You won't see this in the
psh; you'll need to have the server's stderr redirected to a file.

I start up Open Windows with "openwin 2>/tmp/owlog" and run
"tail -f /tmp/owlog &" in my console window.  In my case, 
as soon as I remove that last reference in the psh, I see

  destroy userdict:
  dict[
      ]

in the console.  So why does destroy get executed the second time?
Am I nuts or what?  Enquiring minds want to know.

(I'm running OW2.0 on an SS1.  I don't know if this happens under 1.0.)

=========================================================================
 Mark Smith                                            smith@canon.co.uk
 Canon Research Centre Europe                   ..ukc!uos-ee!canon!smith
-------------------------------------------------------------------------
 soft driven slow and mad like some new language