Python-线程-循环顺序打印abc

import threadingdef showa(): while True: lockc.acquire()# 获取对方的锁,释放自己的锁 print('a', end='') locka.release()def showb(): while True: locka.acquire() print('b', end='') lockb.release() # time.sleep(0.2)def showc(): while True: lockb.acquire() print('c', end='') # sys.stdout.flush() lockc.release() # time.sleep(0.2)if __name__ == '__main__': locka = threading.Lock()# 定义3个互斥锁 lockb = threading.Lock() lockc = threading.Lock()t1 = threading.Thread(target=showa)# 定义3个线程 t2 = threading.Thread(target=showb) t3 = threading.Thread(target=showc)locka.acquire()# 先锁住a,b锁,保证先打印a lockb.acquire()t1.start() t2.start() t3.start()

简单说明:
locka.acquire()
lockb.acquire()
先是a和b锁着故t2、t3线程无法拿到 a和b的锁所以无法执行打印 ; 此时c没有加锁, 故t1执行时可以获取到c锁,故先打印a(t1执行).
【Python-线程-循环顺序打印abc】t1执行完之后是b和c锁着,a没有锁,故可以执行t2了

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