CODEWITHSUNDEEP
pythonmultithreadinglocking
Muhammad Suleman
Muhammad Suleman

Reputation: 797

Python Error Locks

I am new to python and trying to understand the concept of threading.Lock. Below is the example I typed in, 

#!/usr/bin/python
import threading
import Queue

class suleman(threading.Thread):
        def __init__(self,q,lock):
                threading.Thread.__init__(self)
                self.lock=lock
                self.queue=q
        def run(self):
                self.lock.acquire()
                file=open('sul.txt','a')
                q=self.queue.get()
                print q
                q=str(q)
                file.write(q)   
                self.lock.release()
                self.queue.task_done()

queue=Queue.Queue() 
lock=threading.Lock 
for i in range(0,10):
        z1=suleman(queue,lock) 
        z2=suleman(queue,lock)
        z1.setDaemon(True)
        z2.setDaemon(True) 
        z1.start() 
        z2.start()


for i in range(0,10):
        queue.put(i)
queue.join()

Its giving the following error: 

File "lock.py", line 11, in run
    self.lock.acquire()

AttributeError: 'builtin_function_or_method' object has no attribute 'acquire'

Any help would be highly appreciated!

Upvotes: 2

Views: 5565

Answers (1)

Tomo
Tomo

Reputation: 3521

Threading.Lock is not a lock, it creates a lock:

In [1]: import threading

In [2]: threading.Lock
Out[2]: <function thread.allocate_lock>

In [3]: threading.Lock()
Out[3]: <thread.lock at 0x7f9ea666def0>

So you need to change lock=threading.Lock to lock=threading.Lock().

Upvotes: 4

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