线程--守护线程、线程锁、信号量、事件、条件、定时器、队列、池（三）

守护线程

import timefrom threading import Threaddef func1():    while True:        print(‘*‘*10)        time.sleep(1)def func2():    print(‘in func2‘)    time.sleep(5)

t = Thread(target=func1,)t.daemon = Truet.start()t2 = Thread(target=func2,)t2.start()t2.join() #加join后会等待func2结束后在打印print(‘主线程‘)

# 守护进程随着主进程代码的执行结束而结束
# 守护线程会在主线程结束之后等待其他子线程的结束才结束

# 主进程在执行完自己的代码之后不会立即结束 而是等待子进程结束之后 回收子进程的资源# import time# from multiprocessing import Process# def func():#     time.sleep(5)## if __name__ == ‘__main__‘:#         Process(target=func).start()

线程锁

为什么Cpython自带GIL锁还出现死锁，因为是对线程GIL锁，避免不了时间片轮转带来数据不安全

import timefrom threading import Lock,Thread# Lock 互斥锁（只有一个钥匙）
# def func(lock):#     global n#     lock.acquire()#     temp = n#     time.sleep(0.2)#     n = temp - 1#     lock.release()## n = 10# t_lst = []# lock = Lock()# for i in range(10):#     t = Thread(target=func,args=(lock,))#     t.start()#     t_lst.append(t)

# for t in  t_lst: t.join()# print(n)

# 科学家吃面

# noodle_lock  = Lock()# fork_lock = Lock()# def eat1(name):#     noodle_lock.acquire()#     print(‘%s拿到面条啦‘%name)#     fork_lock.acquire()#     print(‘%s拿到叉子了‘%name)#     print(‘%s吃面‘%name)#     fork_lock.release()#     noodle_lock.release()## def eat2(name):#     fork_lock.acquire()#     print(‘%s拿到叉子了‘%name)#     time.sleep(1)#     noodle_lock.acquire()#     print(‘%s拿到面条啦‘%name)#     print(‘%s吃面‘%name)#     noodle_lock.release()#     fork_lock.release()## Thread(target=eat1,args=(‘alex‘,)).start()  # Thread(target=eat2,args=(‘Egon‘,)).start()# Thread(target=eat1,args=(‘bossjin‘,)).start()# Thread(target=eat2,args=(‘nezha‘,)).start()执行上面代码后出现死锁阻塞

解决死锁问题

from threading import RLock   # 递归锁（一串钥匙，多少根据accquire多少次）
fork_lock = noodle_lock  = RLock()   # 一个钥匙串上的两把钥匙def eat1(name):    noodle_lock.acquire()            # 一把钥匙    print(‘%s拿到面条啦‘%name)    fork_lock.acquire()    print(‘%s拿到叉子了‘%name)    print(‘%s吃面‘%name)    fork_lock.release()    noodle_lock.release()

def eat2(name):    fork_lock.acquire()    print(‘%s拿到叉子了‘%name)    time.sleep(1)    noodle_lock.acquire()    print(‘%s拿到面条啦‘%name)    print(‘%s吃面‘%name)    noodle_lock.release()    fork_lock.release()

Thread(target=eat1,args=(‘alex‘,)).start()Thread(target=eat2,args=(‘Egon‘,)).start()Thread(target=eat1,args=(‘bossjin‘,)).start()Thread(target=eat2,args=(‘nezha‘,)).start()

原文地址：https://www.cnblogs.com/mys6/p/10886510.html