[Twisted-Python] returning value after addCallback

Phil Mayers p.mayers at imperial.ac.uk
Thu Aug 9 11:11:45 EDT 2007

> test = PingTracker()
> d = test.check(domain[0], test_opts)
> print d  # this returns Deferred...
> test.SipCallback()   # this returns None

Yes, because no Twisted code has run yet

> reactor.run()

...because you haven't started the reactor.

I don't think you properly understand how Twisted works. Your code is
executed in response to events (packets being received, timers expiring,
reactor startup/shutdown events). The reactor runs the event loop.

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