Event Loop in SO and failover

Hi, All Forte Experts
I have 2 questions:
1. Would any one tell me where can I put the event loop block in a
Service Object?
I tried to put it in the Init to get a timer.tick event, but the SO
hanged to wait there.
How can I do this to let the SO do something at certain time?
2. I have SO doing failover. Can one sleeping SO get any kind of
information when it becomes alive
after the running SO dies?
Thanks a lot for your help.
Alex
Carpe Diem, Seize the Day !
Alex Lee (Li Zhongling)
Forte, Java/CORBA Group
International Business Corporation
Bangalore 560010, India
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Hi,
Thank you all a lot for your help.
For the second question, I explain the situation here. I have a failover
LockManager SO which contains a LockList. When the first running SO dies, I
want the second one to become alive and restore the state of the first one( I
mean the LockList should not be lost). Then I tried to do it in this way:
1. As Daniel Nguyen suggested in Re:Retaining state on failover of SO
(Jan.19,1999), I put one shared object holding one Locklist on the Router
partition. Let the running SO always refresh its contents.
2. I make the SO Transactionaln with Transaction Dialog Duration. On the
client, every time I start a transaction to add or remove lock through SO, I
try to catch the exception "AbortException" (which means the SO dies). To
handle the exception, I use Releaseconnection, then force the backup SO get the
locklist from the shared object on Router partition. In this way, the backup SO
becomes alive and also restore the state.
I think this works. I will also try your suggestion ASAP. However, would you
please tell me how to control the secondary SO not to start and later to start
it? Every time I try to run the app, all the partition will start. And I guess,
I can not new it.
Thanks.
Rds
Alex
Alex,
1) as Arpad mentioned in his posting, you can start task a method which
contains your event loop from the init method.
as for
2), what I've done in the past is to start both primary and secondary SOs,
where the primary SO's event loop begins at start up, but the secondary SO
is dormant.. I created a "monitoring" SO which listens for remote access
exceptions (or distributed access exceptions) and on the death of the first
SO, the second SO's event loop is started. The other option is to not start
the secondary SO until the primary one fails, but there is a lag time for
the SO to come up.
j
Carpe Diem, Seize the Day !
Alex Lee (Li Zhongling)
Forte, Java/CORBA Group
International Business Corporation
Bangalore 560010, India
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Similar Messages

Start Task and Event Loops

I have a Window with an Event Loop that looks like this:
Event Loop
when StartButton.click do
SO.EventLoop;
when StopButton.click do
post SO.Z;
End Event;
I have ServiceObject (SO) that has an EventLoop that looks like this:
Event Loop
when X do
start task Y();
when Z do
exit;
End Event;
The Event Loop on my SO is not catching Z until Y finishes processing.
Does anyone know why? Is there another way do this so I can catch Z
before Y finishes?
Paul Monax
Consultant
Sage It Partners
303.779.3309 x204
[email protected]
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Paul
Could it be that the StopButton.Click() event is not being trapped? That is, the window's event loop is waiting for the SO to complete, as it is a synchronous task. Therefore, use:
when StartButton.Click() do
start task SO.EventLoop();
Anyway, I would think that a better way to do it would be to have the SO's EventLoop running initially. That is, start it (as a separate task) elsewhere (perhaps when the window is opened). Then, when you get the StartButton.Click() event, do:
when StartButton.Click() do
post SO.X; -- This will cause task Y to begin
Hope this helps...
Regards
Sam Keall
[email protected] on 11/08/98 02:42:00
To: [email protected]
cc: (bcc: Sam Keall/GB/ABNAMRO/NL)
Subject: Start Task and Event Loops
I have a Window with an Event Loop that looks like this:
Event Loop
when StartButton.click do
SO.EventLoop;
when StopButton.click do
post SO.Z;
End Event;
I have ServiceObject (SO) that has an EventLoop that looks like this:
Event Loop
when X do
start task Y();
when Z do
exit;
End Event;
The Event Loop on my SO is not catching Z until Y finishes processing.
Does anyone know why? Is there another way do this so I can catch Z
before Y finishes?
Paul Monax
Consultant
Sage It Partners
303.779.3309 x204
[email protected]
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
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Problem using local variable in event loop

I have a state machine from which I want to monitor various controls, including "Start" and "Stop" buttons. Not every state needs to monitor the controls. At present, most states run timed loops. In the first state that reads the front panel, I have an Event structure (inside a While loop) that monitors the various controls' Change Value events. For numeric controls, I update variables (in shift registers) as needed. The "Start" button is used to end the While loop controlling the Event structure, allowing the State to exit to the next state.
My problem comes in subsequent states that employ this same idea. Here, I put a Local Variable bound to the Start button and use the same code, but it frequently happens that when I enter this particular state, I cannot "turn on" the control -- I push the button, but it stays off. Curiously, if it was On when I enter, I can turn it off, but then I'm stuck not being able to turn it on.
I mocked up a very simply routine that illustrates this. There are two sequences (corresponding to the two states). Both use an Event loop with a local variable bound to my Stop button (really this is an LED control with custom colors). I've deliberately moved the "initialization" (the declaration of the control in the block diagram) out of the Event loops -- putting it inside the first loop modifies the behavior in another strange way.
Here's my thinking on how I would expect this to work: The code outside Event Loop 1 should have little effect. Assume the Stop button is initially Off. You will "sit" in Event Loop 1 until you push the Stop button, changing its value to True; this value will be passed out of the Event case and cause the first While loop to exit. You now enter the second sequence. As I understand the Exit tunnel, it defaults to "False", so I'd expect to stay in the second Event loop until I turn the Stop button from On to Off, which will pass out a False, and keep me in the While for one more button push. However, this doesn't happen -- I immediately exit, as though the "True" value of the Stop local variable is being seen and recognized by the Event loop (even though it hasn't changed, at least not in the context of this second loop).
An even more curious thing occurs if I start this routine with the Stop button turned on. Now I start in my Event loop waiting for a change, but this time the change will be from On to Off, which won't cause an exit from the frame. This will be reflected by having the While loop count increment. We should now be in the state of the example above, i.e. in an Event loop waiting for the control to be pushed again, and turned On. However, clicking the control has no effect -- I cannot get it to "turn on".
Where am I going astray in my thinking? What is it about this method of doing things that violates the Labview paradigm? As far as I can tell, what I'm doing is "legal", and I don't see the flaw in my reasoning, above (of course not -- otherwise I'd have fixed it myself!). Note that because I'm using local variables inside Event loops (and I'm doing this because there are two places in my code where I want to do such testing), the Stop control is not latching (as required). Is there something that gets triggered/set when one reads a latched control? Do I need to do this "manually" using my local variable?
I'll try to attach the simple VI that illustrates this behavior.
Bob Schor
Attachments:
Simple Stop Conundrum.vi ‏14 KB

altenbach wrote:
Ravens Fan wrote:
NEVER have multiple event structures that share the same events.
Actually, that's OK. NOT OK is having multiple event structures in the same sequence structure.
See also: http://forums.ni.com/ni/board/message?board.id=170&message.id=278981#M278981
That's interesting. I had always thought I read more messages discouraging such a thing rather than saying it was okay. Your link lead me to another thread with this message. http://forums.ni.com/ni/board/message?board.id=170&message.id=245793#M245793. Now that thread was mainly concentrating on registered user events which would be a different, but related animal.
So if you have 2 event structures they each have their own event queue? So if you have a common event, one structure pulls it off its event queue and it does not affect the other structure's event queue? I guess the inherent problem with this particular VI was that the second event structure locked the front panel. Since the code never got to that 2nd event structure because the first loop never stopped because the change was from true to false. After reading your post and the others, I did some experimentation and turned off the Lock front panel on the 2nd structure, and that prevented the lockup of the program.
Overall, the example VI still shows problems with the architecture and I think your answer should put the original poster on the right track. I think as a rule I would probably never put the same event in multiple structures, I feel there are better ways to communicate the same event between different parts of a program, but I learned something by reading your reply and about how the event structures work in the background. Thanks.

How to handle the 'folder button' in the path command throug Event loop ?

Hi everybody.
Again a stupid question but I can't find the answer.
My VI has a dynamic event loop, to execute the right code depending on user action.
Everything is working well but now I wish to do the following :
I use a 'path command' with the path entry (like for text) and the folder button.
the user click on the path entry -> something A happens.
the user click on the folder button -> something B happens.
As the folder button and the path entry are the same command, how to differenciate those two events in the event structure ?
Maybe there is a value in the node, but I can't find it ...
Thanks for helping !

You can't do exactly what you are wanting to do. The problem is that you can't trigger an action based on clicking the browse button. To implement that you will need to hide the browse button that LV creates and put down a button of your own that you can then track and respond to independently.
Mike...
PS: what is it exactly that you are trying to accomplish?
Certified Professional Instructor
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LabVIEW Champion
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Repeat Loop times out and I don't want it to

Maybe there is a better way to do this but I want an action to take place whenever the modification date of a certain file changes. This is what I use but it errors because of a timeout after about 10 mins if the mod date doesn't change. I need this to be checking all the time.
on idle
tell application "Finder"
set UpdatedOLD to modification date of file aFile
set UpdatedNEW to modification date of file aFile
end tell
repeat while UpdatedOLD = UpdatedNEW
tell application "Finder"
set UpdatedNEW to modification date of file aFile
end tell
end repeat
end idle
How can I get this to work?

Hello
I think you have stepped on a land mine set by OSX 10.6.
There's a fatal bug in Apple Event Manager in 10.6 such that one event in every 65535 events will be lost and never be replied, which will result in Apple Event timeout error on sender. This bug has been reported shortly after the 10.6 release and has not yet been fixed as of 10.6.2.
In your current script, you're continuously sending event to Finder and sooner on later send an event with the specific event id that is doomed to be lost. Judging from the time till you see the time out error, that is 10 min, you're at most sending 65535 / 600 = 109.225 events / sec to Finder. You can reduce the number of events by inserting some delay, e.g. 'delay 1' in your repeat loop but it can only defer the failure.
cf.
Re: Timed Out (Silence)
http://lists.apple.com/archives/applescript-users/2009/Oct/msg00117.html
Re: spurious timeout on nth Apple event on Snow Leopard
http://lists.apple.com/archives/applescript-users/2009/Nov/msg00041.html
A better way to achieve your task would be to let a launchd agent watch the file.
A recipe is as follows.
1) Save a compiled script in :
~/Library/Scripts/launchd/watchdog.1.scpt
with contents :
--SCRIPT
-- Here put your script that is to be triggered when the file is modified.
-- e.g.
tell application "System Events"
display dialog "The file is modified." giving up after 10
end tell
--END OF SCRIPT
2) Save a UTF-8 plain text file in :
~/Library/LaunchAgents/watchdog.1.plist
with contents :
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>watchdog.1</string>
<key>Disabled</key>
<false/>
<key>Program</key>
<string>/usr/bin/osascript</string>
<key>ProgramArguments</key>
<array>
<string>osascript</string>
<string>/Users/USER_NAME/Library/Scripts/launchd/watchdog.1.scpt</string>
</array>
<key>WatchPaths</key>
<array>
<string>POSIX_PATH_TO_THE_FIILE</string>
</array>
</dict>
</plist>
*Change USER_NAME to your user name and POSIX_PATH_TO_THE_FIILE to the POSIX path to the file to be watched.
3) Issue the following command in Terminal to load the launchd agent :
launchctl load ~/Library/LaunchAgents/watchdog.1.plist
Or
3a) Log-out and re-log-in to load the launchd agent.
*The name 'watchdog.1.plist' and 'watchdog.1.scpt' and the script's location '~/Library/Scripts/launchd/' are mere examples. You may change them as you see fit.
cf.
http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/m an5/launchd.plist.5.html
http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/m an1/launchctl.1.html
Good luck,
H
Message was edited by: Hiroto (fixed typo)

Performance question on looping thrue blocks and items (forms 10.1.2.3)

Hi all,
I'm back again in Forms forum : ) !!! and I'm working on a new and very interesting project
version used : Forms [32 bits] Version 10.1.2.3.0 (Production)
A little question for gurus :
On former projects I used to call loops on blocks and item like shown below to do various things such as displaying buttons or showing canvas or different VA depending on the user or scenarios .
PROCEDURE FRM_BLK_ITM_LOOP IS
v_curblk varchar2(90); -- bloc courant
v_curitm varchar2(90); -- item courant
BEGIN
v_curblk := get_form_property(:SYSTEM.CURRENT_FORM,first_block); -- on récupère le 1er block de la form
LOOP
v_curitm := v_curblk||'.'||get_block_property(v_curblk,first_item); -- on récupère le 1er item du block
    WHILE v_curitm != v_curblk||'.'||get_block_property(v_curblk,last_item)
     LOOP -- tant que l'item n'est pas le dernier du block on loop
        v_curitm := v_curblk||'.'||get_item_property(v_curitm,nextitem); -- on récupère l item suivant
        if get_item_property(v_curitm,<some property>) = 'TRUE' then
          --- I can do something.... or adding more conditions if then etc...
        end if;
    END LOOP;
EXIT WHEN v_curblk = get_form_property(:SYSTEM.CURRENT_FORM,last_block); -- on sort losrqu on arrive au dernier block
v_curblk := get_block_property(v_curblk, nextblock); -- on passe au block suivant
END LOOP;
END;In my current project we work on quite huge forms which can have a consequent number of blocks and items.
And we must be very careful regarding performance issues as these forms are accessed via LAN and WAN.
So my question :
This method seems to be quite efficient as it goes thrue blocks and items sequences as they are defined in the builder comparing to go_block -> go_item ->do_something which can easily turn into nightmare-programming.
But I don't really know about network roundtrips with this kind of method.
Is everything done in the app server and then fetched to the client?
What triggers block-level and item-level can be fired during the execution of the loop ? and so one...
Thanks in advance for your advices on this matter.
Jean-Yves

Hmmm, I have to say I never bothered if Forms is in Socket mode or not; I enabled the network statistics, counted the roundtrips and looked for ways to get them lower (my old friend wireshark did also a good job regarding this) ;). But regarding the note Forms 6i uses Socket Connections by default, this might apply to 10g too (or the enhancement request was approved, who knows).
Frankly I am not entirely sure what Socket Mode means; I guess it's the mode the forms applet talks to the forms runtime; wheter it's stateful (via Sockets) or stateless (via HTTP / HTTPS) but this is just a wild guess, and I can't find informations on it quickly. I also enabled networkStats on my Developer Suite only, so I cannot tell if you can enable them on a full-fledged Application Server.
Anyway; as said I just counted the roundtrips and looked where I can avoid them when I made our application ready for WAN.
Another useful tool was Shunra VE Desktop which I used to simulate low bandwith networks with high latencys; I installed it on a virtual XP, started the application and tested how the Application performs. If something looked odd, I looked behind the scenes, built a little testform basing on the code behind and tried out various things; very often you can take advantage of the event bundling forms seems to make when you use several set_xyz calls as Francois also noted; e.g.
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
vRet := get_custom_property('bean_item', 1, 'PROPERTY);most certainly will cause just 1 roundtrip; but if you use get_custom_property in the middle of the set_custom_property calls you will encounter 2 roundtrips as forms needs to synchronize (you get a value from the bean so the forms runtime needs a response) with the forms applet whereas set_custom_property is a one-way-street which can be fired off simultaneous. The same applies to fbean.invoke and fbean.invoke_bool, fbean.invoke_char and the like. Of course if you are using more then one get_custom_property in this case the roundtrips will increase accordingly.
If you want to make use of event bundling make sure you fire off as much set_xyz as you can before forcing forms to synchronize (e.g. with get_xyz, or synchronize, create_timer,...)
cheers

Event loop hang, Windows Forms

My C# console application acquires video frames from a camera and uses OpenCV for per-frame processing. The program is mostly an infinite loop with busy-wait on frame acquisition at the start of the loop and a sleep at the end of the loop
as recommended by OpenCV. Typically CPU utilization is < 15%. I wanted to display 5 video frames in a Form showing different stages of processing so I used the visual designer to subclass Form to my MapDisplay class that has 5 PictureBoxes.
I instantiate MapDisplay with new and use Show() to display it as non-modal. I over-rode Paint() for each PictureBox and in each iteration of my loop I call an overloaded version of Refresh() that has an array of 5 Bitmaps as its argument.
The Bitmaps are made available to the Paint() overloads.
This all works but with very strange mouse behavior. When running from VS there is always a busy cursor when I float over the Form so it can't be selected for movement or resizing. When running outside VS the Form starts with focus but a
mouse click anywhere, even away from the Form, e.g. click Windows Start, causes Form updating to stop. In all cases my main loop remains active and continues to call my Refresh() overload on each iteration.
I think my program structure is atypical but I can see no reason why it's affected by unrelated mouse clicks. I have read solutions to hang problems recommending threading but I don't think I have anything that should be in a separate thread.
The Form code only responds to events and runs no other application code.

Hi
leftwing,
The program is mostly an infinite loop with busy-wait on frame acquisition at the start of the loop and a sleep at the end of the loop as recommended by OpenCV.
Since your case used by OpenCV, i am afraid this is out of our support. I would suggest you can ask in OpenCV official forum Thanks for your understading.
Have a nice day!
Kristin
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Best practices to manage large array inside an event loop?

My program is a multi-event structure, where each event corresponds to a boolean value change by the user. The program begins by reading a .csv file, typically, 50000 rows and 100 columns, of string values. I add some columns, predict the final array size and write to two array controls - input and output. The input array always shows the original data as read from the file. The output array shows the current state of data. The user then presses button that triggers events, in each event I read the output array value, manipulate data, and write back to output array. If an event has to manipulate only the 7th column (for example), then I index that column, manipulate it, and replace that column in the control. I am using 'Value' property node to read and write data to the output array. I NEVER use build array function. I have to update the control at the end of each event to allow the user to see effect of the event.
Typically, my program runs fast. I can go through all events and even repeat them at a good speed. However, when I read .csv file second time, the program slows down, third time even slower. When I read the file, I predict the final size of input and output array and refresh the controls with new values from the .csv file. What am I doing wrong?
1. Should I use shift register in my event structure to read and update output array instead of using property node? Or, should I read and write using a Reference to the control?
2. When I read a control using property node, am I creating a second copy of the data?
3. I believe each time I read or write a control or indicator, LabVIEW switches to threads. This may be causing some delay but I doubt is the reason for my troubles. Right or wrong?
4. Is there a way to deallocate all input and output array control memory? Would it help to write a null array before I refill the controls with a new .csv file?
I can add screenshots of my code. I cannot provide the complete program due to security issues.
Using LV 8.5 Professional on Windows 7 64-bit.
Thanks,
Gurdas
Gurdas Singh
PhD. Candidate | Civil Engineering | NCSU.edu

Crossulz, I updated my code and replaced all property nodes of the output array indicator with shift register. I see some speed/memory improvements (more about that later).
1. Sorry about the wrong terminology. My output array is an indicator and not a control. I was using the word since I use this array to control the saved output. I am not sure I understood what you meant by writing right before the event structure. Did you mean having the terminal between the outer while loop (which has the shift register) and the event structure? Wouldn't that have it update the indicator each time the while loop runs? For the lack of a better solution, I created an event to update the indicator using shift register value. See attached screenshot, "Gurdas_3*.jpg"
2. Okay.
2a. Wires won't work because control and indicators are being manipulated in different events. Shift registers could work, but that means having many shift register, one for each control or indicator. I've read about Feedback nodes, not sure if they exist in LV 8.5.1. If they do, is that an option?
4. See attached screenshot "Gurdas_4*.jpg". I intiliaze the shift register with an empty array and then update it with the data when file is read. Is this what you meant? I still have an input data indicator that I am writing to. But this is one time; this indicator is not read or updated anywhere else.
4a. Notice the 3 branchout data wires just after the file read? Is that creating 3 copies by any chance?
5. See attached screenshot "Gurdas_5*.jpg". This is from the most computation intensive event that uses current data from the shift register. I am indexing many columns out. Is that creating extra copies of the columns?
About the improvements from using shift register. LV's memory usage as reported by Task Manager:
A. Before file read 70 MB
B. After file read 750 MB (includes writing one time to the input data indicator; if I do not write, memory usage is 450 MB)
C. After completing all steps done but never writing to output iindicator array 1.1 GB
D. After completing all steps done and writing to output iindicator array 1.5 GB (this used to be 2 GB previously)
The file I am reading is 47000 rows and 78 columns. I read the file as string. The ondisk size of the file is less than 20 MB.
6. Comparing steps A and B above, why does memory use increase so much more than the actual file size being read?
Thanks for helping me here!
Gurdas Singh
PhD. Candidate | Civil Engineering | NCSU.edu
Attachments:
Gurdas_03_UpdateOutputArray.JPG ‏41 KB
Gurdas_04_New-ReadCSV.JPG ‏125 KB
Gurdas_05_IndexArray.JPG ‏77 KB

Event loop based programming help in c#

Hello everyone . I was reading about node.js and how it does all the work using event loops using a single thread to do all the non-blocking socket I/O . I am trying to implement the same concept in my application which will be doing a lot of socket I/O
including some disk I/O while I will do on a separate thread so that the application doesn't come to its knees . I am going to implement this mode in C# . I have looked around but the answers and solutions given are just too abstract and general . Can you
please help me ?

Have you seen this article (12/25/2014)?
http://www.codeproject.com/Articles/846803/Developing-Applications-With-Express-Framework-And
It uses Visual Studio and includes code and instructions. Also gives you the opportunity to communicate with the author.

Unhandled event loop exception (open a log file in NW Developer Studio)

Hi!
SAP NetWeaver Developer Studio
SAP NetWeaver 7.1 Composition Environment
When I try to open a log file at the SAP Management Console View (i.e. available.log) I get a "Unhandled event loop exception" and the log file content is not shown.
Any hints?
Example:
Log Viewing @ <a href="http://help.sap.com/saphelp_nwce10/helpdata/en/45/e3b0f5f76a2e99e10000000a155369/content.htm">http://help.sap.com/saphelp_nwce10/helpdata/en/45/e3b0f5f76a2e99e10000000a155369/content.htm</a>
Thanks,
Chris

Update:
I have a stack now
Caused by: java.lang.NullPointerException
     at com.sap.managementconsole.jface.JFaceDataPublisher.getEditorForInput(JFaceDataPublisher.java:290)
     at com.sap.managementconsole.jface.JFaceDataPublisher.access$000(JFaceDataPublisher.java:49)
     at com.sap.managementconsole.jface.JFaceDataPublisher$7.run(JFaceDataPublisher.java:180)
     at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
     at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:123)
     ... 20 more
-Chris

Redundancy and Failover setup for 2 MPLS link with 2 different countries

Hi Sir/Madam,
We have 2 MPLS link and both links are active (from COUNTRY A to COUNTRY B) and we also have 2 partners who are located in COUNTRY B with same building but with different offices and each partner will be using each MPLS link. For example, PARTNER A will use the 1st MPLS link and PARTNER B will use the 2nd MPLS link and we want to have a failover setup (please see sample design below). What is the best solution for COUNTRY A and B to have a full redundancy and failover setup/network?
Any recommendation and sample configuration will be a big help for me. Your feedback is highly appreciated.
Thank you in advance.
Best regards,
Marvin

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
MPLS links, eh. You mean your MPLS facing ports have actual MPLS labels? Or do you mean your WAN links are running across a MPLS network, but the handoff isn't MPLS?
Country A's two routers are your company's devices? Do you have interior connectivity between them?
Country B's two routers - do they or can they have interior connectivity?
What routing protocols are being used (and where)?

Multiple "generate user event" in event loop

Hello.
1.) I am wondering if you can user a "generate user event" into an event loop to create a quasi-state machine.
For example create an event loop with the events "event a", "event b," "event c," and so on. The in "event a" put in a function to generate a user event to call "event b". Then "event b" will call "event c" and so on.
2.) If this is possible, then can u put multiple generate user events into a single event loop and have it queue the generate user events up. For example have the "event 1" case use the "generate user event" 3 times (generating "event 7" "event 8" and "event 9.") to call the next three future event cases in that order?
Thanks
Charlie C.

Of course it is possible, easiest with simply writing signaling properties. (See attached examples, LabVIEW 7.1).
You have to be very careful that you don't create trigger loops, e.g. event A triggers Event B, which triggers Event A ... ad infinitum! :0
Example "Multievents": event 1 triggers event 2, which triggers event 3.
Example Multievents2": event 1 triggers events 2-3-2-stop in sequence.
Message Edited by altenbach on 09-28-2005 01:26 PM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
MultiEvents.vi ‏57 KB
MultiEvents2.vi ‏72 KB

Is it ok to trigger 2 event loops off the same control?

I have two event loops which need to trigger when the Exit button is clicked on. Is it ok to trigger both loops off the same control? It has been working great, but I'm not sure if there could be an issue. Please see below. Thank You!
Solved!
Go to Solution.

sfrosty wrote:
Another point may be that I have 50 ms wired to the timer in the MENU event structure and don't want any delay in the MAIN Event structure. Not sure if this is a valid point.
Why? Are you doing something else in that loop?
I would recommend moving your menue stuff into your main event loop. You will thank yourself later.
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How to override the event loop

As a windows game developer, I have always overridden the application message loop to make sure that graphics were rendered when the CPU was idle, and still being able to process windows messages like keyboard/mouse events. CPU is then maxed out (except when a forced sleep or v-sync is enabled) to give highest performance on graphics, making a simple clear opengl window render at 3500 frames per second (I know this is idiotic but I'm trying to make a point).
Now that I'm porting my game engine (c++ code) to cocoa, I am struggling with how to implement the main loop. I could use a timer but this will fix the framerate and might be slow. It will prevent me to use the CPU to its full extent.
So: is there some kind of OnIdle event I can override? Or do I have to do the Event loop processing myself? And can anyone tell me how to do something like this? Is there a tutorial or a book or anything I can study to learn about this? I presume this is lower level API.
Any help is appreciated!
Dirk.

etresoft wrote:
Michael may profess ignorance about MacOS X applications, but he is still 100% correct. You need to study the architecture and find the best way to work with it. The first thing to know is that the CPU is irrelevant. Let the GPU handle your graphics - that is what it does best. You do want your CPU to be as idle as possible. Approach it from a device-driver or event-driven perspective.
Just to clarify that I'm not a total noob trying to write his first program: of course I will not overly use the CPU if not necessary. I completely agree with what you guys say about maximizing CPU usage. My game engine on windows will put the CPU to sleep when it's not necessary making my engine perform very good with almost no CPU usage.
But... when I want to test if changes to my engine/shaders/... improve or degrade performance of the renderings, I want to be sure that everything is maxed out so that I can be sure that the difference is correct. On maxed out CPU/GPU, I will notice the difference when framerate goes for example from 2000 to 1900 while this will not be visible when just at 60 fps and a lot of free time. I will see 60 fps even when my code is worse. That's why I need to be able to test this.
Anyway, as I said, I completely agree and I will certainly do my very best to make sure that CPU is not overly used. So my question remains: how can I make sure that I have everything I need at the time I need it while I will do my best to make sure nothing more is used?
Timer-events at 1/60th of a second is not the answer...
Using threads for these things is not the answer... I use them for other things (loading from disk/processing data/generating data)
But are there other options?
Can you point me to where I can learn more about the architecture and its possibilities?

SMTP Routes, DNS and Failover

Hi !
I'm configuring an outgoing server (i.e. only a private listener) on ESA C370 with AsyncOS 8.0.1.
I use the Internet's Root DNS Servers, and my default SMTP route is empty. My ESA is connected to 3 networks : production (default gateway), administration and failover (1 interface/network).
I would like to deploy a failover solution with an extra ESA on the failover network : if I lose my internet connection (impossible to join DNS and remote MX), my ESA would redirect all its mails to the extra ESA.
How can I do that ?
Thank you for your help.
Best Regards
Quentin

The ESA has no way to automatically fallback to a static IP if DNS in unreachable. The best on-box solution I can suggest is manually changing the 'All Other Domains' SMTP Routes entry when such an event occurs.
I hope this helps!
- Jackie

Event Loop in SO and failover

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