Question

嗨我需要创建2个线程，其中重复写入时间作为 HH：MM：SS字符串每秒100次进入全局变量。第二个线程将重复读取一天中的时间该变量的字符串每秒两次并尝试将其显示到屏幕，但该线程中的代码应该保证相同 string永远不会连续写入两次。结果是第二个线程每秒只显示一次屏幕。我试过以下代码，但它不起作用

    import threading
    import time
    c = threading.Condition()
    flag = 0      #shared between Thread_A and Thread_B
    val = ''

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:
                time.sleep(0)
                flag = 1
                a=range(1,101)
                for i in a:
                    val=time.strftime("%H:%M:%S", time.localtime(time.time()))
                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:
                #time.sleep(1)
                flag = 0
                a=range(0,2)
                for i in a:
                    print str(val)
                #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()

共享时间变量在两个线程之间

0 个答案: