How do I close the udpport with 2021b? Error Unable to bind to LOCALHOST and LOCALPORT. Verify that the LOCALPORT is not in use...

I am switching my app to use the new udpport. It works the first time I use it. However, when I close the app, then run it again and attempt to connect, it seems that the resource is still in use:

Error: "Unable to bind to LOCALHOST and LOCALPORT. Verify that the LOCALPORT is not in use, and that LOCALHOST and LOCALPORT are valid for IPADDRESSVERSION "IPV4"."

I used to just use delete(isntrfind) or instrreset, but those don't seem to work. Now, if I start a udpport, then close the app, I get the error above. I have to close matlab to get it to forget the udp port.

Thanks!

[Rakesh]

Hi Brandon.

Add close button in first app where you can add clear udpport in the "ButtonPushedFcn" of close button.

In the second app in the startup function you can reconfigure the udpport .

Answer 1

[Dor Luzon]

Hey,

The only thing that actually close the conneciton for me is using the udpport function delete.

udpPort.delete();

flushing and clearing the object doesn't work.

Answer 2

[Walter Roberson]

in theory it needs to have the variable holding the port cleared. I suggest that you put in an onCleanup to ensure that it is done.

[Brandon Krick]

What command? fclose errors out. clear does not work. It still binds the next time it is called

app.ZMotor.portName=udpport("byte","LocalPort",7777) % This one works
% do some stuff with the port (writeline, etc.)

clear app.ZMotor.portName %Try to clear the port, deleted the variable but doesn't work
app.ZMotor.portName=udpport("byte","LocalPort",7777) %Try again and get an error:

Unable to bind to LOCALHOST and LOCALPORT. Verify that the LOCALPORT is not in use, and that LOCALHOST

and LOCALPORT are valid for IPADDRESSVERSION "IPV4"..

I also cannot connect to the device with the manufacturer provided software after making the udpport in matlab. Thanks.

[Walter Roberson]

I don't think you can clear a struct member; I think you would need to assign something else such as [] over top of app.ZMotor.portName

[Brandon Krick]

Thanks. That worked. Silly structure syntax...