python多进程子进程不运行问题--未解决

原创

danssion 2022-11-11 10:56:43 博主文章分类：python ©著作权

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在升级程序到 python3.9 后，异步非阻塞的子进程起不来了，实际代码在python3.6 版是可以运行的：

程序逻辑及相关使用方式大概是这样的

def job(x):
    return x * x

if name == “main”:
    pool multiprocessing.Pool()
    res = [pool.apply_async(target=job, (i,)) for i in range(3)]
    print [r.get() for r in res]

更接近的代码是这样的：

#第一个 python.py 

import time, os

class Student(object):
    def __init__(self, name, score):
        self.name = name
        self.score = score

    def print_score(self):
        print('%s: %s' % (self.name, self.score))

    def get_grade(self):
        if self.score >= 90:
            return 'A'
        elif self.score >= 60:
            return 'B'
        else:
            return 'C'

    def output(self):
        print('Run task %s (%s)...' % (self, os.getpid()))
        i = 0
        while True:
            time.sleep(1)
            self.print_score()
            time.sleep(2)
            print("grade:", self.get_grade())
            i += 1

在另外的文件进行多进程

from multiprocessing import Pool
import os, time
from job import Student


def facade_it(ts, name):
    p = Pool(4)
    for i in range(5):
        stu = Student.Student(name[i], (i + 15) * ts)
        p.apply_async(stu.output)
        print("up apply_async")

    print('Waiting for all subprocesses done...')
    p.close()
    p.join()

    print('All subprocesses done.')


if __name__ == '__main__':
    l = ['Allen', "Belle", "Carl", "David", "Even"]
    ts = 5
    facade_it(ts, l)