线程锁

# -*- coding:utf-8 -*- 
# Author：Brownyangyang
import threading
import time


def sayhi(n):
    lock.acquire()  ##加锁，只有我这个线程才可以解锁，其他线程无法修改值
    global num
    num += 1
    lock.release()  ##解锁


lock = threading.Lock()  ##实例化一把锁
num = 0

#if __name__ == ‘__main__‘:

#start_time=time.time()

item_liyan = []
for i in range(500):
    t = threading.Thread(target=sayhi,args=(i,))
    #t.setDaemon(True) ##把当前线程设置成守护线程，主进程执行完不会等子进程

    t.start()
    #t2.start()
    item_liyan.append(t)

# for j in item_liyan:
#     j.join() ##join等待子线程运行完毕


print("number %s" %num)
print(threading.current_thread()) ##打印主线程

    #print(t1.getName())
    #print(t2.getName())