为什么我的过程产生四次而不是两次? - python

我有三个脚本,Win7x64上的Python 2.7.9(kivy)。

multiprocessing_1

def Multiprocessing_3():
    print "Hohoo!"
    import multiprocessing_3
    multiprocessing_3.LetseGo()

print "It'se me,",__name__," !!"

if __name__ == "__main__":
    import multiprocessing_2
    multiprocessing_2.main()

多重处理_2

import multiprocessing

def main():
    print "YA!"
    import multiprocessing_1
    Multiprocessing3 = multiprocessing.Process(target=multiprocessing_1.Multiprocessing_3,args=(''))
    Multiprocessing3.start()

multiprocessing_3

def LetseGo():
    print "YAHoooooooo!"

我的问题是关于在执行python multiprocessing_1.py之后抛出的输出:

It'se me, __main__!!
YA!
It'se me, multiprocessing_1!!
It'se me, __parents_main__!!
It'se me, multiprocessing_1!!
Hohoo!
YAHoooooooo!

或在此处查看输出:http://i.imgur.com/ROtLAaZ.png

_1__main__开头,然后导入并调用_2,然后生成_1.Multiprocessing_3进程,该进程导入并执行_3.LetseGo()

但是,正在发生的事情是_1实际上运行了四次,而不是我实际预期的两次。

你能告诉我为什么吗?

python大神给出的解决方案

发生这种情况是因为您正在Windows上运行代码,并且Windows需要在子进程中使用re-import your __main__ module(恰好是multiprocessing_1.py)来执行传递给multiprocessing.Process的功能。此外,您需要对要在子级中调用的函数Multiprocessing_3进行腌制,以便将其从父进程发送到子级,并且要在子级中取消选中该函数,需要导入该函数所属的模块,再次是multiprocessing_1。因此,每个输出的解释是:

It'se me, __main__!!  # multiprocessing_1 is imported when you execute it directly.
YA!
It'se me, multiprocessing_1!!  # multiprocessing_2.py calls 'import multiprocessing_1'
It'se me, __parents_main__!!  # after you call multiprocessing3.start(), the child process needs to re-import the `__main__` module of your script, which is multiprocessing_1.py
It'se me, multiprocessing_1!!  # This import happens so that the Multiprocessing_3 function can be unpickled in the child.
Hohoo!
YAHoooooooo!