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    <p>Generally it's better to avoid threads when you can. It's very difficult to write a threaded application correctly, and even more difficult to know you got it right. Since you're writing a GUI application, it's easier for you to visualize how to do so, since you already have to write your application within an asynchronous framework. </p> <p>The important thing to realize is that a GUI application is doing a whole lot of nothing. It spends most of its time waiting for the OS to tell it that something has happened. You can do a lot of stuff in this idle time as long as you know how to write long-running code so it doesn't block.</p> <p>You can solve your original problem by using a timeout; telling your GUI framework to call back some function after a delay, and then resetting that delay or starting another delayed call.</p> <p>Another common question is how to communicate over the network in a GUI application. Network apps are like GUI apps in that they do a whole lot of waiting. Using a network IO framework (like <a href="http://twistedmatrix.com/" rel="nofollow noreferrer">Twisted</a>) makes it easy to have both parts of your application wait cooperatively instead of competitively, and again alleviates the need for extra threads.</p> <p>Long-running calculations can be written iteratively instead of synchronously, and you can do your processing while the GUI is idle. You can use a generator to do this quite easily in python.</p> <pre><code>def long_calculation(param, callback): result = None while True: result = calculate_next_part(param, result) if calculation_is_done(result): break else: yield callback(result) </code></pre> <p>Calling <code>long_calculation</code> will give you a generator object, and calling <code>.next()</code> on the generator object will run the generator until it reaches either <code>yield</code> or <code>return</code>. You would just tell the GUI framework to call <code>long_calculation(some_param, some_callback).next</code> when it has time, and eventually your callback will be called with the result.</p> <p>I don't know GTK very well, so I can't tell you which gobject functions you should be calling. With this explanation, though, you should be able to find the necessary functions in the documentation, or at worst, ask on a relevant IRC channel.</p> <p>Unfortunately there is no good general-case answer. If you clarify with exactly what you're trying to do, it would be easier to explain why you don't need threads in that situation.</p>
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    1. POBeginner-level Python threading problems
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    1. COhttps://launchpad.net/rotor-control-software Why would I not need threads in the RCS class, specifically when calling Start() from the GUI? This little dummy program I've posted here is really just an exercise in getting threads to work.
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    2. COIf you can get a file descriptor for the serial interface, you can probably set that in nonblocking mode and make nonblocking reads and writes on the interface. I wouldn't recommend using that library, though. I looked it over quickly, and it isn't very well-written.
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    3. COWell thats great to hear! Unfortunately, the rotor only has a serial interface. Know of any decent serial modules for Python?
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