python(进程池)

# Author: Sooele
from  multiprocessing import Process, Pool,freeze_support
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__':
    #freeze_support()
    pool = Pool(processes=3) #允许进程池同时放入3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()
    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()