From: djlewis <djlewis@...>
Date: 2008-08-13T08:52:36+09:00
Subject: Re: WIN32OLE -- cannot terminate Excel process

On Aug 12, 6:31 pm, Adam Shelly <adam.she...@gmail.com> wrote:
> On 8/12/08, David Mullet <david.mul...@gmail.com> wrote:
>
> > If I modified that code to this...
>
> >    ews = nil
> >    ewb = nil
> >    excel = nil
> >    WIN32OLE.ole_free( ews)
> >    WIN32OLE.ole_free( ewb)
> >    WIN32OLE.ole_free( excel)
> >    GC.start
>
> > ...the Excel process terminated properly.
>
> > My suggestions:
>
> > A) Set object variables to nil before calling ole_free.
>
> I can see how you can free up object memory with
>   ews = nil;
>   #...
>   GC.start
>
> But I'm not sure what calling ole_free after assigning to nil could
> possibly do...
> How is
>   ews = nil;
>   WIN32OLE.ole_free( ews)
>
> any different from:
>   WIN32OLE.ole_free( nil)
> ?
>
> -Adam

Thanks for all the suggestions.  One of my problems was due to running
in a debugger (NetBeans) and stopping at a breakpoint to look at
processes, and sometimes even just killing execution right there.
That prevented the Excel process from terminating, perhaps because GC
did not finish its job.

Still, during debugging, that's a common occurrence, and can lead to a
lot of Excel processes hanging around.  So I think the function simply
to kill all automation instances of Excel is handy to have while
debugging, used, say, at the beginning of the program.  Here it is...

def kill_excel_automation_processes
  wmi = WIN32OLE.connect("winmgmts://")
  processes = wmi.ExecQuery("select * from win32_process where
commandline like '%excel.exe\"% /automation %'")
  processes.each do |process|
    Process.kill('KILL', process.ProcessID)
  end
end

I don't know if there's a way to get something called upon manual
termination in the debugger.  at_exit { } does not seem to do it in
NetBeans.