Is Powerpoint still a single instance app?

Howard,

What about iterating through the current window collection before attempting to
get a PPT object; if any of the windows belong to PowerPoint, then somebody's
using it.

PowerPoint 11 (2003) down to PPT97:
"PP11FrameClass"
"PP10FrameClass"
"PP9FrameClass"
"PP97FrameClass"

-----------------------------------------
Steve Rindsberg, PPT MVP
PPT FAQ: www.pptfaq.com
PPTools: www.pptools.com
================================================

http://www.standards.com/; See Howard Kaikow's web site.
"Steve Rindsberg" wrote in message
...
Depending on user settings and version, PPT may automatically create a
blank
presentation on startup, so presentation count might be 0 or 1 even if
you've
invoked it. That's why I suggested the other rigamarole re checking the
presentation's name (always Presentation1 until it's been saved) and the
path
(blank until it's been saved).

Yes, I realize that, and there may even be no presentation.
That's why I'm trying the following.
-------------------------
I've come up with the following, is it valid?

1. Make sure that PowerPoint is not running.

2. Run a VB 6 program that creates a NEW instance of PowerPoint.

3. While the program in step 2 is still running, and PPT has not been Quit,
run another VB 6 program that enumerates desktop processes, call the output
List 1.

4. While the PPT from step 2 is still running, start PowerPoint from the
desktop. Since I had already created an instance in step 2, both should end
up using the same instance as PowerPoint is multi-use, single instance.

5. Now, again run the program that enumerates desktop processes, call the
output List 2.

Both List 1 and List 2 give the same handle for PowerPoint, and the same
number of top level windows,

List 1 does not list an active presentation, whilst List 2 lists
Presentation1. So the first bit of info is that the PowerPoint window will
be that of the latest use of Powerpoint. So this doesn't help solve my
problem.

However, the Total Thread Windows is 9 for List 1, 11 for List 2

I am enumerating the processes using code based on KB article 183009 and
only incrementing the counters when PP11FrameClass is found.

So, is it safe to ASSuME that I can determine that there is another user
using my PowerPoint object if the thread count is greater than the number
reported by List 1?

"Steve Rindsberg" wrote in message
...

Howard,

What about iterating through the current window collection before
attempting to
get a PPT object; if any of the windows belong to PowerPoint, then
somebody's
using it.

See my posting of a few minutes ago where I enumerated processes.
The sticky point is that my New instance of PPT is still open when I do the
iterations, i.e., I'm trying to determine whether I can Quit.

I am hoping that I can do this based on the thread count, as discussed in my
other posting.

it is necessary to do this iterating only if the presentation count is 0, as
i have already closed my, if any, presentation.

Not yet there, the code from the KB article is enumerating Windows, not
processes, so doesn't handle case where presentation count = 0.

Appears that I can do the deed by iterating processes.
Needs further testing.

See my posting of a few minutes ago where I enumerated processes.
The sticky point is that my New instance of PPT is still open when I do the
iterations, i.e., I'm trying to determine whether I can Quit.

So the problem at this point is:

Having fired off your own instance of PPT, how can you be certain that a user
hasn't in the interim invoked PPT on their own?

If you know that you started by invoking PPT when it wasn't previously open,
then you should also be able to maintain a count of any presentations you've
opened or created; if someone manually starts/opens another presentation, then
.Presentations.Count will be higher than your total, so it wouldn't be safe to
force PPT to quit.

Does that oonch us a bit closer? ;-)


I am hoping that I can do this based on the thread count, as discussed in my
other posting.

it is necessary to do this iterating only if the presentation count is 0, as
i have already closed my, if any, presentation.


-----------------------------------------
Steve Rindsberg, PPT MVP
PPT FAQ: www.pptfaq.com
PPTools: www.pptools.com
================================================

"Steve Rindsberg" wrote in message
...
Having fired off your own instance of PPT, how can you be certain that a
user
hasn't in the interim invoked PPT on their own?

If you know that you started by invoking PPT when it wasn't previously
open,
then you should also be able to maintain a count of any presentations
you've
opened or created; if someone manually starts/opens another presentation,
then
Presentations.Count will be higher than your total, so it wouldn't be safe
to
force PPT to quit.

Does that oonch us a bit closer? ;-)

No.

Because the presentation count could still be 0.

Enumerating processes appears to resolve the problem, but I want to simplify
the code.

In article , Howard Kaikow wrote:
"Steve Rindsberg" wrote in message
...
Having fired off your own instance of PPT, how can you be certain that a
user
hasn't in the interim invoked PPT on their own?

If you know that you started by invoking PPT when it wasn't previously
open,
then you should also be able to maintain a count of any presentations
you've
opened or created; if someone manually starts/opens another presentation,
then
Presentations.Count will be higher than your total, so it wouldn't be safe
to
force PPT to quit.

Does that oonch us a bit closer? ;-)

No.

Because the presentation count could still be 0.

Possibly for that instant, but closing an instance of PPT with no open
presentations will do no harm.


Enumerating processes appears to resolve the problem, but I want to simplify
the code.


-----------------------------------------
Steve Rindsberg, PPT MVP
PPT FAQ: www.pptfaq.com
PPTools: www.pptools.com
================================================

"Steve Rindsberg" wrote in message
...
Possibly for that instant, but closing an instance of PPT with no open
presentations will do no harm.

It sure does.

It closes the other uses of PPT.
Users, and other code, whould not be very ubhappy if theirPPT suddenly
disappeared.

To restate the problem.
----------------------------
I was using the wrong terminology.

PowerPoint is a Multi-use, single Instance app.

Assume that PPT is not running.

Then my code creates a NEW instance of PPT.
Then, while my code is running, PPT is again started by a user from the
desktop or via another piece of code.
Etc.

AFAIK, it is possible for all uses of PPT to have, at any point in time, a
Presentations.Count of 0, so I cannot tell whether I should Quit my instance
of PPT, based on Presentation count, lest it affect the other uses.

At some point, I would do the following:

1. DoEvents
2. Disable keyboard and mouse input
3. test for number of PowerPoint critters.
4. If only 1 critter, Quit PPT, otherwise let it live.
5. Enable keyboard and mouse input
6. exit from my code.

Enumerating processes, using say, the example at ALLAPI, lists a different
working set size for each use of PPT.

In my case, all I need to know is whether there is one use or more, does not
matter how many. If 1 use, then I can safely Quit my instance of Powerpoint.

I need to study the ALLAPI, and other examples, to make sure the info is
what I need.

My app has been doing what Steve suggests for almost 4 years without any
reports of problems. There is one and only one instance of Powerpoint
(powerpnt.exe) running regardless of how many programs have a reference
count to it or if a user opened the GUI for Powerpoint. I check to make
sure that presentations count = 0 then I call the Powerpoint quit method.
If a user has started the GUI and closed the pres1 (or whatever) default
presentation Powerpoint creates then indeed when you quit PowerPoint it
closes the GUI. If other programs have connected to that instance of
Powerpoint then they would get an exception when they referenced that
object. But that is why there is a big disclaimer on the MS web site that
tells us not to use Powerpoint in an automated fashion. We are pretty much
out there on our own. I had originally hoped they would expose the
reference count through a method or property but I didn't see it.

Good luck.

"Howard Kaikow" wrote in message
...
"Steve Rindsberg" wrote in message
...
Possibly for that instant, but closing an instance of PPT with no open
presentations will do no harm.

It sure does.

It closes the other uses of PPT.
Users, and other code, whould not be very ubhappy if theirPPT suddenly
disappeared.

To restate the problem.
----------------------------
I was using the wrong terminology.

PowerPoint is a Multi-use, single Instance app.

Assume that PPT is not running.

Then my code creates a NEW instance of PPT.
Then, while my code is running, PPT is again started by a user from the
desktop or via another piece of code.
Etc.

AFAIK, it is possible for all uses of PPT to have, at any point in time, a
Presentations.Count of 0, so I cannot tell whether I should Quit my
instance
of PPT, based on Presentation count, lest it affect the other uses.

At some point, I would do the following:

1. DoEvents
2. Disable keyboard and mouse input
3. test for number of PowerPoint critters.
4. If only 1 critter, Quit PPT, otherwise let it live.
5. Enable keyboard and mouse input
6. exit from my code.

Enumerating processes, using say, the example at ALLAPI, lists a
different
working set size for each use of PPT.

In my case, all I need to know is whether there is one use or more, does
not
matter how many. If 1 use, then I can safely Quit my instance of
Powerpoint.

I need to study the ALLAPI, and other examples, to make sure the info is
what I need.