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我来解释一下锁

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方大侠百宝箱

#1 Created at ... [Delete] [Delete and Lock User]

python的官方文档中有这么一句话：

A primitive lock is a synchronization primitive that is not owned by a particular thread when locked. 

我理解的锁是：

primitive lock锁并不属于任何一个线程，可以把它认为是一个公共变量。如果想要参与到锁的游戏规则中，则参加的线程都必须要在函数体中使用acquire()和release()两种方法（一旦有线程不遵守该规则将会打破该平衡）。

  • acquire()

    查询锁状态，如锁是locked状态，则同步堵塞；如锁是unlocked状态，则将其上锁。

  • release()

    解锁

上述概念可用以下代码解释

import threadingimport timeLOCK = Falsedef run_thread_1():    global LOCK    while LOCK:        print("run_thread_1 is waiting")        time.sleep(1)    LOCK = True    print("run_thread_1 lock the LOCK")    print("run_thread_1 is doing something")    time.sleep(5)    LOCK = False    print("run_thread_1 release the LOCK")def run_thread_2():    global LOCK    while LOCK:        print("run_thread_2 is waiting")        time.sleep(1)    print("run_thread_2 lock the LOCK")    LOCK = True    print("run_thread_2 is doing something")    time.sleep(3)    LOCK = False    print("run_thread_2 release the LOCK")    task1 = threading.Thread(target=run_thread_1)task2 = threading.Thread(target=run_thread_2)task1.start()task2.start()task1.join()task2.join()print("finish")

方大侠百宝箱

#2 Created at ... [Delete] [Delete and Lock User]

之前提交代码的格式错误了。

请看下面这个。

import threading
import time

LOCK = Falsedef run_thread_1():
   global LOCK
   while LOCK:
      print("run_thread_1 is waiting")
      time.sleep(1)
   LOCK = True   print("run_thread_1 lock the LOCK")
   print("run_thread_1 is doing something")
   time.sleep(5)
   LOCK = False   print("run_thread_1 release the LOCK")

def run_thread_2():
   global LOCK
   while LOCK:
      print("run_thread_2 is waiting")
      time.sleep(1)
   print("run_thread_2 lock the LOCK")
   LOCK = True   print("run_thread_2 is doing something")
   time.sleep(3)
   LOCK = False   print("run_thread_2 release the LOCK")
   
task1 = threading.Thread(target=run_thread_1)
task2 = threading.Thread(target=run_thread_2)
task1.start()
task2.start()
task1.join()
task2.join()
print("finish")
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