Duration optional? Forever?

[kevinelliott]

What if we want the UDP listen to be forever or until interrupted in some way?

[xenoken]

Hi @kevinelliott, thanks for using udp!
Version 3.0.0 introduces an optional duration parameter for udp.listen(). So now it's possible to listen indefinitely.
To stop listening, please call udp.close() on the udp instance.

[kevinelliott]

Hi @xenoken ... thank you for the library!

Upon removal of the duration, my application exits immediately and does not receive any UDP packets. I'm assuming now I need some kind of main state loop with sleeps in order to prevent the application from exiting?

[xenoken]

That's correct @kevinelliott.
When timeout is specified, udp.listen() returns a future that completes only after the time has run out. When timeout is not specified, udp.listen() returns a future that is already completed (with value true). In the latter case listen() behaves like a synchronous function call that returns immediately.

[kevinelliott]

Ahh, I see... what I was looking for was a never ending listen... I need to process millions of UDP packets over time.

[xenoken]

Yes, udp.listen() is indeed never ending. It will keep listening for packets even though the function returns immediately. for example:

var receiver = await UDP.bind(Endpoint.loopback(port: Port(54321));

var success = await receiver.listen((datagram){
// ...your callback code here...
});

// even though the execution reaches this point, receiver is still listening to udp packets.
// what is required now is a way to prevent the application from exiting.

// ...end of program here...