九.多进程

import multiprocessing
import time

def run(name):
    time.sleep(2)
    print(‘hello‘,name)

if __name__ == ‘__main__‘:
    for i in range(10):
        p = multiprocessing.Process(target=run,args=(‘man %s‘%i,))
        p.start()

from multiprocessing import Process,Queue
import threading

def f(q):
    q.put([123,‘abc‘])

if __name__ == ‘__main__‘:
    q = Queue()
    
    p = Process(target=f, args=(q,))
    p.start()
    print(q.get())   
    

from multiprocessing import Process,Pipe

def a(message):
    message.send([123,"fghr"])
    message.close

if __name__ == "__main__":
    pointa,pointb=Pipe()

    p=Process(target=a,args=(pointa,))
    p.start()
    print(pointb.recv())

from multiprocessing import Process, Manager
import os
def f(d, l):
    d[os.getpid()] =os.getpid()
    l.append(os.getpid())
    print(l)

if __name__ == ‘__main__‘:
    with Manager() as manager:
        d = manager.dict() #{} #生成一个字典，可在多个进程间共享和传递

        l = manager.list(range(5))#生成一个列表，可在多个进程间共享和传递
        p_list = []
        for i in range(10):
            p = Process(target=f, args=(d, l))
            p.start()
            p_list.append(p)
        for res in p_list: #等待结果
            res.join()

        print(d)
        print(l)

from  multiprocessing import Process, Pool
import time
import os

def Foo(i):
    time.sleep(2)
    print("in process",os.getpid())
    return i + 100

def Bar(arg):
    print(‘-->exec done:‘, arg,os.getpid())

if __name__ == ‘__main__‘:
    pool = Pool(processes=3) #允许进程池同时放入5个进程
    print("主进程",os.getpid())
    for i in range(10):
        pool.apply_async(func=Foo, args=(i,), callback=Bar) #callback=回调
        #pool.apply(func=Foo, args=(i,)) #串行
        #pool.apply_async(func=Foo, args=(i,)) #并行
    print(‘end‘)
    pool.close()#这里join一定是在close之后，且必须要加join，否则主进程不等待创建的子进程执行完毕
    pool.join() #进程池中进程执行完毕后再关闭，如果注释，那么程序直接关闭。.join()