python-multithreading

Why does the code below work only with multiprocessing.dummy , but not with simple multiprocessing . import urllib.request #from multiprocessing.dummy import Pool #this works from multiprocessing import Pool urls = ['http://www.python.org', 'http://www.yahoo.com','http://www.scala.org', 'http://www.google.com'] if __name__ == '__main__': with Pool(5) as p: results = p.map(urllib.request.urlopen, urls) Error : Traceback (most recent call last): File "urlthreads.py", line 31, in <module> results = p.map(urllib.request.urlopen, urls) File "C:\Users\patri\Anaconda3\lib\multiprocessing\pool.py",

How do I get a thread to return a tuple or any value of my choice back to the parent in Python? I suggest you instantiate a Queue.Queue before starting the thread, and pass it as one of the thread's args: before the thread finishes, it .put s the result on the queue it received as an argument. The parent can .get or .get_nowait it at will. Queues are generally the best way to arrange thread synchronization and communication in Python: they're intrinsically thread-safe, message-passing vehicles -- the best way to organize multitasking in general!-) If you were calling join() to wait for the

If I have a thread in an infinite loop, is there a way to terminate it when the main program ends (for example, when I press Ctrl + C )? rogeriopvl Check this question. The correct answer has great explanation on how to terminate threads the right way: Is there any way to kill a Thread in Python? To make the thread stop on Keyboard Interrupt signal (ctrl+c) you can catch the exception "KeyboardInterrupt" and cleanup before exiting. Like this: try: start_thread() except (KeyboardInterrupt, SystemExit): cleanup_stop_thread() sys.exit() This way you can control what to do whenever the program is