多進程調用

# 多進程調用（大部分與多線程的操做同樣）
# 調用方式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')

# 調用方式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   # 設置守護進程
        p.start()
        p_list.append(p)
    # for i in p_list:
    #     i.join()

    print('end...')


# 查看進程的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      # 父進程的進程pid(pycharm)
    # process id: 4116      # 當前.py文件運行的pid
    # ------------------------------
    # title: alex
    # parent process: 4116      # 父進程的pid即當前.py文件運行的pid
    # process id: 6392      # 產生的子進程的pid

 

# Process類的方法與屬性
# 構造方法：
# Process(group[, target[, name[, args[, kwargs]]]])
# group: 線程組，目前尚未實現，庫引用中提示必須是None
# target: 要執行的方法
# name: 指定進程名
# args / kwargs: 要傳入方法的參數
#
# 實例方法：
# is_alive() 返回進程是否在運行
# join([timeout]) 阻塞當前上下文環境的進程，直到調用此方法的進程終止或到達指定的timeout
# start() 進行準備就緒，等待cpu調度
# run() start()方法調用run方法，若是實例進程時未制定傳入target，這start執行默認run方法
# terminate() 無論任務是否完成，當即中止工做進程
#
# 屬性：
# daemon 和線程的setDaemon功能同樣
# name 進程名字
# pid 進程號

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')