python-Event事件处理进程同步

#!/usr/bin/python
from multiprocessing import Process,Event
import os,time

def A(e):
    print "block Process :starting"
    e.wait()
    print "event is set >>",e.is_set()

def B(e,t):
    print "non-block Process :starting"
    e.wait(t)
    print "non-event is set >>",e.is_set()

e=Event()
m=Process(target=A,args=(e,))
m.start()
n=Process(target=B,args=(e,3))
n.start()

print "main process"
time.sleep(8)
e.set()
print "main  is over"