python多线程变量_python 多线程 共同写一个变量

import threading

import time

c = threading.Condition()

flag = 0 #shared between Thread_A and Thread_B

val = 20

class Thread_A(threading.Thread):

def init(self, name):

threading.Thread.init(self)

self.name = name

def run(self):

global flag

global val #made global here

while True:

c.acquire()

if flag == 0:

print "A: val=" + str(val)

time.sleep(0.1)

flag = 1

val = 30

c.notify_all()

else:

c.wait()

c.release()

class Thread_B(threading.Thread):

def init(self, name):

threading.Thread.init(self)

self.name = name

def run(self):

global flag

global val #made global here

while True:

c.acquire()

if flag == 1:

print "B: val=" + str(val)

time.sleep(0.5)

flag = 0

val = 20

c.notify_all()

else:

c.wait()

c.release()

a = Thread_A("myThread_name_A")

b = Thread_B("myThread_name_B")

b.start()

a.start()

a.join()

b.join()