多进程调用

# 多进程调用（大部分与多线程的操作一样）
# 调用方式1
from multiprocessing import Process
import time


def f(name):
    time.sleep(1)
    print(‘hello‘, name, time.ctime())


if __name__ == ‘__main__‘:
    p_list = []
    for i in range(3):
        p = Process(target=f, args=(‘alex‘,))
        p_list.append(p)
        p.start()
    for i in p_list:
        i.join()
    print(‘end‘)

# 调用方式2
from multiprocessing import Process
import time


class MyProcess(Process):
    # def __init__(self):
    #     super(MyProcess, self).__init__()
    #     self.name = name

    def run(self):
        time.sleep(1)
        print(‘hello‘, self.name, time.ctime())


if __name__ == ‘__main__‘:
    p_list = []
    for i in range(3):
        p = MyProcess()
        # p.daemon = True   # 设置守护进程
        p.start()
        p_list.append(p)
    # for i in p_list:
    #     i.join()

    print(‘end...‘)


# 查看进程的pid
from multiprocessing import Process
import os, time


def info(title):
    print(‘title:‘, title)
    print(‘parent process:‘, os.getppid())
    print(‘process id:‘, os.getpid())


def f(name):
    info(‘function f‘)
    print(‘hello‘, name)


if __name__ == ‘__main__‘:
    info(‘main process line‘)
    time.sleep(1)
    print(‘-‘ * 30)
    p = Process(target=info, args=(‘alex‘,))
    p.start()
    p.join()

    # title: main process line
    # parent process: 1792      # 父进程的进程pid(pycharm)
    # process id: 4116      # 当前.py文件运行的pid
    # ------------------------------
    # title: alex
    # parent process: 4116      # 父进程的pid即当前.py文件运行的pid
    # process id: 6392      # 产生的子进程的pid

# Process类的方法与属性
# 构造方法：
# Process(group[, target[, name[, args[, kwargs]]]])
# group: 线程组，目前还没有实现，库引用中提示必须是None
# target: 要执行的方法
# name: 指定进程名
# args / kwargs: 要传入方法的参数
#
# 实例方法：
# is_alive() 返回进程是否在运行
# join([timeout]) 阻塞当前上下文环境的进程，直到调用此方法的进程终止或到达指定的timeout
# start() 进行准备就绪，等待cpu调度
# run() start()方法调用run方法，如果实例进程时未制定传入target，这start执行默认run方法
# terminate() 不管任务是否完成，立即停止工作进程
#
# 属性：
# daemon 和线程的setDaemon功能一样
# name 进程名字
# pid 进程号

from multiprocessing import Process
import time


class MyProcess(Process):
    def __init__(self, num):
        super(MyProcess, self).__init__()
        self.num = num

    def run(self):
        time.sleep(1)
        print(self.is_alive(), self.num, self.pid)
        time.sleep(1)


if __name__ == ‘__main__‘:
    p_list = []
    for i in range(10):
        p = MyProcess(i)
        p_list.append(p)

    for p in p_list:
        p.start()

    print(‘main process end‘)