65 - 请解释什么是线程锁，以及如何使用线程锁
原创
65 - 请解释什么是线程锁，以及如何使用线程锁
原创
ruochen
修改于 2021-06-11 10:05:16
修改于 2021-06-11 10:05:16
请解释什么是线程锁，以及如何使用线程锁
- 线程锁: 目的是将一段代码锁住，一旦获得锁权限，除非释放线程锁，否则其他任何代码都无法获得锁权限
- 为什么需要线程锁
- 多线程同时在完成特定的操作时，由于并不是原子操作，所以在完成操作的过程中可能会被打断，去做其他的操作
- 可能产生脏数据
- 例如，一个线程读取变量n 【初始值是0】，然后n++, 最后输出n，当访问n++后，被打断，由另外的线程做同样的工作，这时n被加了2次，所以n最后等于2，而不是1
from atexit import register
from threading import Thread, Lock, currentThread
from time import sleep, ctime
import random
lock = Lock()
print(type(lock))
def fun():
lock.acquire() # 加锁
for i in range(5):
print('Thread Name', '=', currentThread().name, 'i', '=', i)
sleep(random.randint(1, 5))
lock.release() # 释放锁
def main():
for i in range(3):
Thread(target=fun).start()
@register
def exit():
print('线程执行完毕: ', ctime())
main()<class '_thread.lock'>Thread Name = Thread-13 i = 0Thread Name = Thread-13 i = 1Thread Name = Thread-13 i = 2Thread Name = Thread-13 i = 3Thread Name = Thread-13 i = 4Thread Name = Thread-14 i = 0Thread Name = Thread-14 i = 1Thread Name = Thread-14 i = 2Thread Name = Thread-14 i = 3Thread Name = Thread-14 i = 4Thread Name = Thread-15 i = 0Thread Name = Thread-15 i = 1Thread Name = Thread-15 i = 2Thread Name = Thread-15 i = 3Thread Name = Thread-15 i = 4from atexit import register
from threading import Thread, Lock, currentThread
from time import sleep, ctime
import random
lock = Lock()
print(type(lock))
def fun():
# lock.acquire() # 加锁
for i in range(5):
print('Thread Name', '=', currentThread().name, 'i', '=', i)
sleep(random.randint(1, 5))
# lock.release() # 释放锁
def main():
for i in range(3):
Thread(target=fun).start()
@register
def exit():
print('线程执行完毕: ', ctime())
main()<class '_thread.lock'>Thread Name = Thread-16 i = 0Thread Name = Thread-17 i = 0Thread Name = Thread-18 i = 0Thread Name = Thread-16 i = 1Thread Name = Thread-17 i = 1Thread Name = Thread-18 i = 1Thread Name = Thread-17 i = 2Thread Name = Thread-16 i = 2Thread Name = Thread-17 i = 3Thread Name = Thread-18 i = 2Thread Name = Thread-18 i = 3Thread Name = Thread-18 i = 4Thread Name = Thread-17 i = 4Thread Name = Thread-16 i = 3Thread Name = Thread-16 i = 4原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。
原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。
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