Question on threads

[Jonathan Shao]

On Fri, Apr 11, 2008 at 3:29 PM, Steve Holden <steve at holdenweb.com> wrote:

> Jonathan Shao wrote:
>
> > Hi all,
> >  I'm a beginner to Python, so please bear with me.
> >  Is there a way of guarenteeing that all created threads in a program
> > are finished before the main program exits? I know that using join() can
> > guarentee this, but from the test scripts I've run, it seems like join()
> > also forces each individual thread to terminate first before the next thread
> > can finish. So if I create like 20 threads in a for loop, and I join() each
> > created thread, then join() will in effect cause the threads to be executed
> > in serial rather than in parallel.
> >
> >
> No it won't, as in fact there is no mechanism to force a thread to
> terminate in Python. When you join() each created thread the main thread
> will wait for each thread to finish. Supposing the longest-lived thread
> finished first then all others will immediately return from join().
>
> The only requirement it is imposing is that all sub-threads must be
> finished before the main thread terminates.
>
> regards
>  Steve
> --
> Steve Holden        +1 571 484 6266   +1 800 494 3119
> Holden Web LLC              http://www.holdenweb.com/
>


I guess I'm doing something wrong with join(). Here's a test script I wrote
up...

import threading
import time
class TestThread(threading.Thread):
    def __init__(self, region):
        self.region = region
        threading.Thread.__init__(self)
    def run(self):
        for loop in range(10):
            print "Region " + str(self.region) + " reporting: " + str(loop)
            time.sleep(2)
for x in range(10):
    thr = TestThread(x)
    thr.start()
    thr.join()
raw_input()
In this script thread 0 will finish first... Am I doing something wrong with
join()?
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