import multiprocessing
import os
def run_proc(name):
  print('Child process {0} {1} Running '.format(name, os.getpid()))
if __name__ == '__main__':
  print('Parent process {0} is Running'.format(os.getpid()))
  for i in range(5):
    p = multiprocessing.Process(target=run_proc, args=(str(i),))
    print('process start')
    p.start()
  p.join()
  print('Process close')

import multiprocessing
import os
import time
def run_task(name):
  print('Task {0} pid {1} is running, parent id is {2}'.format(name, os.getpid(), os.getppid()))
  time.sleep(1)
  print('Task {0} end.'.format(name))
if __name__ == '__main__':
  print('current process {0}'.format(os.getpid()))
  p = multiprocessing.Pool(processes=3)
  for i in range(6):
    p.apply_async(run_task, args=(i,))
  print('Waiting for all subprocesses done...')
  p.close()
  p.join()
  print('All processes done!')

import multiprocessing
import os
import time
def run_task(name):
  print('Task {0} pid {1} is running, parent id is {2}'.format(name, os.getpid(), os.getppid()))
  time.sleep(1)
  print('Task {0} end.'.format(name))
if __name__ == '__main__':
  print('current process {0}'.format(os.getpid()))
  p = multiprocessing.Pool(processes=3)
  for i in range(6):
    p.apply(run_task, args=(i,))
  print('Waiting for all subprocesses done...')
  p.close()
  p.join()
  print('All processes done!')

from multiprocessing import Process, Queue
import os, time, random
# 寫數(shù)據(jù)進程執(zhí)行的代碼:
def proc_write(q,urls):
  print('Process(%s) is writing...' % os.getpid())
  for url in urls:
    q.put(url)
    print('Put %s to queue...' % url)
    time.sleep(random.random())
# 讀數(shù)據(jù)進程執(zhí)行的代碼:
def proc_read(q):
  print('Process(%s) is reading...' % os.getpid())
  while True:
    url = q.get(True)
    print('Get %s from queue.' % url)
if __name__=='__main__':
  # 父進程創(chuàng)建Queue，并傳給各個子進程：
  q = Queue()
  proc_writer1 = Process(target=proc_write, args=(q,['url_1', 'url_2', 'url_3']))
  proc_writer2 = Process(target=proc_write, args=(q,['url_4','url_5','url_6']))
  proc_reader = Process(target=proc_read, args=(q,))
  # 啟動子進程proc_writer，寫入:
  proc_writer1.start()
  proc_writer2.start()
  # 啟動子進程proc_reader，讀取:
  proc_reader.start()
  # 等待proc_writer結(jié)束:
  proc_writer1.join()
  proc_writer2.join()
  # proc_reader進程里是死循環(huán)，無法等待其結(jié)束，只能強行終止:
  proc_reader.terminate()

from multiprocessing import Process, Pipe
def send(pipe):
  pipe.send(['spam'] + [42, 'egg'])  # send 傳輸一個列表
  pipe.close()
if __name__ == '__main__':
  (con1, con2) = Pipe()              # 創(chuàng)建兩個 Pipe 實例
  sender = Process(target=send, args=(con1, ))   # 函數(shù)的參數(shù)，args 一定是實例化之后的 Pip 變量，不能直接寫 args=(Pip(),)
  sender.start()                  # Process 類啟動進程
  print("con2 got: %s" % con2.recv())       # 管道的另一端 con2 從send收到消息
  con2.close()                   # 關(guān)閉管道

from multiprocessing import Process, Pipe
def talk(pipe):
  pipe.send(dict(name='Bob', spam=42))      # 傳輸一個字典
  reply = pipe.recv()               # 接收傳輸?shù)臄?shù)據(jù)
  print('talker got:', reply)
if __name__ == '__main__':
  (parentEnd, childEnd) = Pipe()         # 創(chuàng)建兩個 Pipe() 實例，也可以改成 conf1， conf2
  child = Process(target=talk, args=(childEnd,)) # 創(chuàng)建一個 Process 進程，名稱為 child
  child.start()                  # 啟動進程
  print('parent got:', parentEnd.recv())     # parentEnd 是一個 Pip() 管道，可以接收 child Process 進程傳輸?shù)臄?shù)據(jù)
  parentEnd.send({x * 2 for x in 'spam'})     # parentEnd 是一個 Pip() 管道，可以使用 send 方法來傳輸數(shù)據(jù)
  child.join()                  # 傳輸?shù)臄?shù)據(jù)被 talk 函數(shù)內(nèi)的 pip 管道接收，并賦值給 reply
  print('parent exit')