Python 2.7中的线程

Question

我是Python新手。我试图用严格的阅读器优先级来编写读者 - 作者问题，出于某种原因，python不考虑我的全局变量'nor'。线程定义是否存在问题？

import threading 

readers=threading.BoundedSemaphore(1) 

writers=threading.BoundedSemaphore(1) 

mutex=threading.BoundedSemaphore(1) 

nor=0 
class reader(threading.Thread): 
    def __init__(self): 
     threading.Thread.__init__(self) 
    def run(self): 
     while(1): 
      writers.acquire() 
      mutex.acquire() 
      if(nor==0): 
       readers.acquire() 
      nor=nor+1 
      mutex.release() 

      print "I just read\n" 

      mutex.acquire() 
      if(nor==1): 
       readers.release() 

      nor=nor-1 
      mutex.release() 
      writers.release() 

class writer(threading.Thread): 
    def _init__(self): 
      threading.Thread.__init__(self) 
    def run(self): 
     while(1):   
     writers.acquire() 
     readers.acquire() 

     print "I just wrote\n" 

     writers.release() 
     readers.release() 

r1=reader() 
r2=reader() 
r3=reader() 
w1=writer() 
w2=writer() 

r1.start() 
r2.start() 
r3.start() 
w1.start() 
w2.start() 

Answer 1

尝试tiping

global nor 

类里面，也没有调用之前。之后

def run(self):