Widgets are not thread safe, see Threads and QObjects: Although QObject is reentrant, the GUI classes, notably QWidget and all its subclasses, are not reentrant. They can only be used from the main thread. And see more definitions here: Reentrancy and Thread-Safety You should only use widgets in the main thread, and use signal and … Read more
Do this: from threading import Thread def func1(): print(‘Working’) def func2(): print(“Working”) if __name__ == ‘__main__’: Thread(target = func1).start() Thread(target = func2).start()
I still think using Join is simpler. Record the expected completion time (as Now+timeout), then, in a loop, do if(!thread.Join(End-now)) throw new NotFinishedInTime();
TL;DR Making the Right Choice: We have walked through the most popular forms of concurrency. But the question remains – when should choose which one? It really depends on the use cases. From my experience (and reading), I tend to follow this pseudo code: if io_bound: if io_very_slow: print(“Use Asyncio”) else: print(“Use Threads”) else: print(“Multi … Read more
A somewhat clumsy ascii-art to demonstrate the mechanism: The join() is presumably called by the main-thread. It could also be called by another thread, but would needlessly complicate the diagram. join-calling should be placed in the track of the main-thread, but to express thread-relation and keep it as simple as possible, I choose to place … Read more
One way I’ve seen is to pass a mutable object, such as a list or a dictionary, to the thread’s constructor, along with a an index or other identifier of some sort. The thread can then store its results in its dedicated slot in that object. For example: def foo(bar, result, index): print ‘hello {0}’.format(bar) … Read more
Never do long running tasks in response to a button, event, etc as these are on the event thread. If you block the event thread, the ENTIRE GUI will be completely unresponsive resulting in REALLY pissed off users. This is why Swing seems slow and crusty. Use Threads, Executors, and SwingWorker to run tasks NOT … Read more
The interface IEnumerable<T> is not thread safe. See the documentation on http://msdn.microsoft.com/en-us/library/s793z9y2.aspx, which states: An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and its behavior is undefined. The enumerator does not have exclusive … Read more
I have implemented something like this and it works fine: private Timer mTimer1; private TimerTask mTt1; private Handler mTimerHandler = new Handler(); private void stopTimer(){ if(mTimer1 != null){ mTimer1.cancel(); mTimer1.purge(); } } private void startTimer(){ mTimer1 = new Timer(); mTt1 = new TimerTask() { public void run() { mTimerHandler.post(new Runnable() { public void run(){ //TODO … Read more
The ThreadPool is always there, however, there are a finite number of threads allocated to the pool based on the number of processors. For ASP.NET applications, it is generally a bad idea to use Threads unless you really are starting off an Async process and know that there won’t be a large number of requests … Read more