# coding:utf-8 from time import sleep import thread

def long_io(cb):     print "開始呼叫long_IO"

    def func(callback):         print "start long_IO"         sleep(2)         callback(1)         print "end long_IO "     thread.start_new_thread(func, (cb,))     print "long_IO函式返回"

def on_finish(ret):     print "呼叫了回撥函式"     print "ret %s" % ret     print "結束了回撥函式"

def req_a():     print "start calling a"     long_io(on_finish)     print "end a"

def req_b():     print "start calling b"     sleep(1)     print "end b"

# 同步概念： if __name__ == '__main__':     """模擬主迴圈排程"""     req_a()     print '-------------------'     req_b()     while True:         pass