help netreceive find an available TCP port

[Ant1r]

For several years now, [netreceive] accepts the [listen PORTNUMBER( message, which allows to skip the port number argument, and look for an available TCP port at run time.

Unfortunately, two things make this a bit complicated and inelegant:

• every unsuccessful attempt prints this error to the console:

  netreceive: listen failed: Address already in use (98)

• there is no patch level feedback on the success or failure of the attempt (so you need to test another way, like with a dedicated [netsend]).

I see a simple solution: why not adding a [try PORTNUMBER( command, which wouldn't print any error but would send -1 to the second outlet (number of open connections) instead?