多线程死锁

Posted 2021-11-30 reyinever

# 死锁
# 如果程序中的多个线程互相等待对方持有的锁，而在得到对方的锁之前都不释放自己持有的锁，就会导致程序不能继续运行，# 这就是死锁。
# 死锁的表现是程序死循环
# 防止死锁：
# （1）全局考虑定义一个获得锁的顺序并且整个程序都遵守遵守
# （2）释放锁的时候按加锁的反序释放即可

import threading
import time
lock1=threading.Lock()
lock2=threading.Lock()

class T1(threading.Thread):
    def __init__(self,name):
        threading.Thread.__init__(self)
        self.name=name

    def run(self):
        lock1.acquire()
        # time.sleep(1)
        print(‘in thread ‘,self.name)
        time.sleep(2)
        lock2.acquire()
        print(‘in lock2 of T1‘)
        lock2.release()
        lock1.release()

class T2(threading.Thread):
    def __init__(self,name):
        threading.Thread.__init__(self)
        self.name=name

    def run(self):
        lock2.acquire()
        print(‘in thread ‘,self.name)
        time.sleep(1)
        lock1.acquire()
        print(‘in lock1 of T2‘)
        lock1.release()
        lock2.release()

def test():
    t1=T1(‘t1‘)
    t2=T2(‘t2‘)
    t1.start()
    t2.start()

if __name__ == ‘__main__‘:
    test()