多进程的调用(multiprocessing.Process)

# multiprocessing是一个支持使用与threading模块类似的API来产生进程的包。multiprocessing包同时提供了本地和远程并发操作，通过使用子进程而非线程有效地绕过了全局解释器锁。因此，multiprocessing模块允许程序员充分利用给定机器上的多个处理器。
import multiprocessing, time, os

# def pro(name):
#  print('hello', name, time.ctime())
#
# if __name__ == '__main__':
#  l = []
#  for t in range(4):
#     t = multiprocessing.Process(target=pro, args=('alex',))
#     t.start()
#     l.append(t)
#  for t in l:
#     t.join()
#  print('end...')


# class MyProcess(multiprocessing.Process):
#  def __init__(self, city):
#     super(MyProcess, self).__init__()
#     self.city = city
#
#  def run(self):
#     '''继承同样重写run方法'''
#     print('hello', self.name, time.ctime()) # self.name代表进程名MyProcess-1,MyProcess-2,MyProcess-3,MyProcess-4
#
# if __name__ == '__main__':
#  l = []
#  for t in range(4):
#     t = MyProcess('China')
#     # t.daemon = True # 和线程不一样的是，进程是daemon且不是方法而是属性，直接赋值True就行
#     t.start()
#     l.append(t)
#  for t in l:
#     t.join()
#  print('end...')


def info(title):
   print('title:', title)
   print('父进程ID:', os.getppid()) # os.getppid()所运行进程的父进程ID，主进程的父进程是pycharm程序
   print('该进程ID:', os.getpid()) # os.getpid()所运行进程ID

def f(name):
   info(name)
   print('hello', name)

if __name__ == '__main__':
   f('main process line')
   time.sleep(1)
   p = multiprocessing.Process(target=f, args=('alex',))
   p.start()
   p.join()