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TCP Listen not listening


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Hi

I'm trying to run double loop program. One while loop acquires data the other transfers it via tcp/ip. Both loops are closed in a Flat Sequence Structure.

Before the the sequence I put TCP Listen and set the timeout to -1 (forever). After the FSS I close the TCP connection.

In client that receives the data I open the connection, while loop where I get the data and closing connection after.

It happens that the Listen doesn't wait for the incomming connection. From the observations I see that the source of the problem

might be not properly closed connection, because if I wait a moment I can run it again without a problem.

Does anyone has any idea what might be keeping the connection open eventhough I close it myself?

Is it possible that the error is somewhere else?

I tried to use various ports - the results are the same.

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The problem may not be in your LabVIEW code; it may be related to the remote device not freeing ephemeral ports in a timely fashion. The error code might tell you more.

Try using a fixed timeout (5 seconds) and check the error returned from the TCP open.

See these threads from the NI forums...

http://forums.ni.com/ni/board/message?boar...ssage.id=240177

http://forums.ni.com/ni/board/message?boar...=215544#M215544

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Thanks for the clues.

The error number I get is 248, which seems not to be described anywhere. I found a flag that does not change the time itself but allows reuse of the port without

waiting. Well setting it doesn't help, but I'm still digging :)

Any ideas on the error?

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