How to close TCP port in LV 4.1?

[ksem]

I've used the "TCP Listen" VI and the combination of "TCP Create Listener" & "TCP Wait on Listener" to accept a socket connection. That works fine, but I do not want the app to listen for any more requests once it has a connection. I would expect "TCP Listen" to close the listener once it has a connection, but it does not. When using the Create/Wait Listener VIs I call "Close Connection" on the Listener and even though I do not get an error, the port is still being listened to.
What could be going wrong?

[Ben]

Could you post an IMAGE (LV 4.1 is getting scarce these days) of your code so we can take a look?

It sounds as if the listen is being invoked again.

There have been some changes and fixes implemented since LV 4.1 so I can not say that I have seen this issue previously.

Trying to offer what little help I can,

Ben


Ben Rayner
Certified LabVIEW Developer
www.DSAutomation.com

[ksem]

Thanks for responding.
Going to reply in multiple posts as I have more than 3 attachments.

The first attachment (orig.jpg) is what existed when I noticed that listening socket seemed to be staying open. This is very similar to an NI tcp server example which I'm attaching as well (example.gif). I don't have the code anymore, but I did modify the existing code to replicate the example exactly and I still saw the same behavior.

[ksem]

I also tried the other method of creating a listener, waiting on the listener, and closing the listener when a connection is made. The close of the listener returned "success" yet a "netstat -a" still showed that it was still listening on that port.

Thanks again,
Kevin

[ksem]

A note on the "close listener" diagram: The "abort" input terminal was documented as being ignored, though I still tried giving it a "true" when the default "false" didn't seem to work.

[Ben]

OK,

How about an image of how these sub-VI are being called.

The extensive use of Globals makes me nervous but I can not spot anything solid that would cause me to suspect a race condition.

Images of these VI's being called will shut me up.

Ben

[ksem]

The sub-vi has multiple callers, but there's only one call per message id. Attached is one of the callers.

[Ben]

Is there any possibility to get this app loaded and saved as at least LV 6.0?

At the current rate, I am running the risk of wasting alot of your time before I can be sure if I can even help!

Short of that, I am concerned about race conditions due the extensive use of globals.

Ben

[ksem]

I can't get it saved in a newer version...
Do you really think the globals could be part of the problem? I may try to write a test app with the connection code minus the globals to see if that behaves any differently.

Thanks,
Kevin

[Ben]

Not the globals themselves but how they are used.

I never use globals I devlop myself.

I have worked with them in others code.

I suspect a race condition that is a result of over using globals.

If I could look at the entire app, I may be able to spot the race condition.

Ben