RE: threading

[Edwin.Madari]

1. check out the Caveats for thread module: http://docs.python.org/lib/module-thread.html

Threads interact strangely with interrupts: the KeyboardInterrupt exceptionwill be received by an arbitrary thread. (When the signal module is available, interrupts always go to the main thread.)

i.e., all threads (including main) to catch interrupt exceptions, and propagate that information to other threads.

2. since there is no way to interrupt a sleep (not aware of any), sleep is not the choice. use something else like napping. I mean, take shorter intervals of sleep, check every thing is fine and go back to napping. if something is fishy - go catch it.

hope that helps.
Edwin
-----Original Message-----
From: py************************************************ **@python.org
[mailto:py***************************************** *********@python.org]
On Behalf Of Rhamphoryncus
Sent: Thursday, August 14, 2008 2:52 PM
To: py*********@python.org
Subject: Re: threading
On Aug 14, 3:30*am, "Mathieu Prevot" <[e-mail]:

2008/8/13 Parimala <[e-mail]>:

Hello,

* * * *I am using python2.5.1 version to run my test scripts. Iwant to use
'threading' module in my tests. As a startup program, I had run the
following one.

importthreading
import sys
import time

def hello():
* i=0
* try:
* * while i<10:
* * * print "hi"
* * * time.sleep(1)
* * * i+=1
* except KeyboardInterrupt:
* * print 'KeyboardInterrupt'
* * raise KeyboardInterrupt

try:
* thread=threading.Thread(target=hello,args=())
* thread.start()
except KeyboardInterrupt:
* print 'KeyboardInterrupt'
* raise KeyboardInterrupt

once program starts, problem is..
I am not able to abort the thread using (CTRL+C) KeyboardInterrupt. *While
running if I press CTRL+C, it won't generate any exception until the end of
the execution. Once the execution gets over, *it will give "Exception
exceptions.KeyboardInterrupt in <module 'threading' from
'C:\python25\lib\threading.py'ignored" this message and exits.

I had gone through some documents, it says if a thread is joined with
.join() method then we can't stop that process until it releases the lock
what it acquired. But in the above program I didn't use .join() method but
still I am not able to abort the thread.

Could you please suggest me how can I abort the thread at any point in time
using CTRL+C.

Hi,

a terminate method is given here:http://sebulba.wikispaces.com/recipe+thread2

so you can terminate the thread by:

(...)
t.start()
(...)

while True:
* try:
* * #some code
* except KeyboardInterrupt:
* * t.terminate()
* * break

Mathieu

(For some reason the OP hasn't come through to groups.google.com..
odd)

Note that it won't interrupt any blocked I/O, which is often what you
need the most. If your threads are CPU-bound you can simply have them
check a flag and exit if it becomes True.
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