[comp.windows.ms.programmer] Another instance? There ISN'T another instance!

lwallace@javelin.sim.es.com (Raptor) (04/11/91)

So all of a sudden Windows informs my application that it's not the
only instance of it running: hPrevInstance != 0.  I've seen this in
Codeview, and my application's behavior confirms it (it only lets
itself run once and displays an error otherwise).

I've looked in the task list (double-click on the desktop) and gee,
there's no copy of my application present before I run it.

However, this doesn't happen with a newly-rebuilt version of the
generic application which I also examined under Codeview, so it's got
to be something wrong with my program, but what?

The only thing I can think of now is to hack in some code to try to
find out about this mythical other instance that's supposedly running,
and see if that tells me anything.  (I may also re-install my SDK
since I recently contracted the 4096 virus.  Hey, if anyone knows who
wrote this thing, I'd like to have a LONG talk with them...  Gad, not
even a "ha ha I infected you", just a disk crash.)

It's a large model program (for now, please no lectures on large
model), so Windows should not even let it run if there is indeed
another copy running.

Anyone else ever see this?  Suggestions?
-- 
            Lynn Wallace           |           I do not represent E&S.
Evans and Sutherland Computer Corp.|   Internet: lwallace@javelin.sim.es.com
      Salt Lake City, UT 84108     |           Compu$erve:  70242,101
	      Revenge is a dish best not served at all.

lwallace@javelin.sim.es.com (Raptor) (04/11/91)

Never mind.  It was another Stupid User Trick.  E-mail me if you want
details.

-- 
            Lynn Wallace           |           I do not represent E&S.
Evans and Sutherland Computer Corp.|   Internet: lwallace@javelin.sim.es.com
      Salt Lake City, UT 84108     |           Compu$erve:  70242,101
	      Revenge is a dish best not served at all.

jja@wsl.ie (John Allen on wsl) (04/18/91)

In article <1991Apr10.190201.16284@javelin.sim.es.com> lwallace@javelin.sim.es.com (Raptor) writes:
>So all of a sudden Windows informs my application that it's not the
>only instance of it running: hPrevInstance != 0.  I've seen this in
>
>I've looked in the task list (double-click on the desktop) and gee,
>there's no copy of my application present before I run it.
>

If you application does not display it's window then it won't appear in the task
list and you won't have any way of interacting with it, and therefore there won't
be any way to close it down.

Hope this helps man.
-- 
People that don't know want to know from the people that do know and if the 
poeple that do know don't tell the people that don't know then the people
that don't know still won't know.
				   "Don't quote me on any issue whatsoever."