I've been teaching myself Python from the tutorial routed at "http://
www.tutorialspoint.com/python/index.htm". It's worked out pretty
well, but when I copied its multithreading example from the bottom of
the page at "http://www.tutorialspoint.com/python/
python_multithreading.htm" and tried to run it I got the error
messages:
C:\Users\kvnsmnsn\Python>python mt.py
Traceback (most recent call last):
File "mt.py", line 38, in <module>
thread = myThread(threadID, tName, workQueue)
File "mt.py", line 10, in __init__
self.name = name
File "C:\Python27\lib\threading.py", line 667, in name
assert self.__initialized, "Thread.__init__() not called"
AssertionError: Thread.__init__() not called
I don't really understand why it's giving me these messages.
<__initialized> gets set to <True> when <__init__()> gets called.
Granted my Python program calls <__init__()> with only one parameter,
and the constructor in "threading.py" takes _seven_ parameters, but
all but one have default values, so a call with just one parameter
should be legal. Why then is <__initialized> getting set to <True>?
My code follows.
Kevin Simonson
import Queue
import threading
import time
exitFlag = 0
class myThread (threading.Thread):
def __init__(self, threadID, name, q):
self.threadID = threadID
self.name = name
self.q = q
threading.Thread.__init__(self)
def run(self):
print "Starting " + self.name
process_data(self.name, self.q)
print "Exiting " + self.name
def process_data(threadName, q):
while not exitFlag:
queueLock.acquire()
if not workQueue.empty():
data = q.get()
queueLock.release()
print "%s processing %s" % (threadName, data)
else:
queueLock.release()
time.sleep(1)
threadList = ["Thread-1", "Thread-2", "Thread-3"]
nameList = ["One", "Two", "Three", "Four", "Five"]
queueLock = threading.Lock()
workQueue = Queue.Queue(10)
threads = []
threadID = 1
# Create new threads
for tName in threadList:
thread = myThread(threadID, tName, workQueue)
thread.start()
threads.append(thread)
threadID += 1
# Fill the queue
queueLock.acquire()
for word in nameList:
workQueue.put(word)
queueLock.release()
# Wait for queue to empty
while not workQueue.empty():
pass
# Notify threads it's time to exit
exitFlag = 1
# Wait for all threads to complete
for t in threads:
t.join()
print "Exiting Main Thread"
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