Question on threads

[Steve Holden]

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
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