Question related to multiprocessing.Process

[Cen Wang]

Hi, when I use multiprocessing.Process in this way:

from multiprocessing import Process

class MyProcess(Process):

def __init__(self):
Process.__init__(self)

def run(self):
print 'x'

p = MyProcess()
p.start()

It just keeps printing 'x' on my command prompt and does not end. But I think MyProcess should print an 'x' and then terminate. I don't why this is happening. I'm using Win7 64 bit, Python 2.7.3. Any idea? Thanks in advance.

 

[Chris Angelico]

Hi, when I use multiprocessing.Process in this way:

from multiprocessing import Process

class MyProcess(Process):

def __init__(self):
Process.__init__(self)

def run(self):
print 'x'

p = MyProcess()
p.start()

It just keeps printing 'x' on my command prompt and does not end. But I think MyProcess should print an 'x' and then terminate. I don't why this is happening. I'm using Win7 64 bit, Python 2.7.3. Any idea? Thanks in advance.

Multiprocessing on Windows requires that your module be importable. So
it imports your main module, which instantiates another MyProcess,
starts it, rinse and repeat. You'll need to protect your main routine
code:

if __name__=="__main__":
p = MyProcess()
p.start()

ChrisA

 

[Cen Wang]

Thanks! It now works!

Multiprocessing on Windows requires that your module be importable. So

it imports your main module, which instantiates another MyProcess,

starts it, rinse and repeat. You'll need to protect your main routine

code:



if __name__=="__main__":

p = MyProcess()

p.start()



ChrisA

 

[Cen Wang]

Thanks! It now works!

Multiprocessing on Windows requires that your module be importable. So

it imports your main module, which instantiates another MyProcess,

starts it, rinse and repeat. You'll need to protect your main routine

code:



if __name__=="__main__":

p = MyProcess()

p.start()



ChrisA

 

[Terry Reedy]

Multiprocessing on Windows requires that your module be importable. So
it imports your main module, which instantiates another MyProcess,
starts it, rinse and repeat. You'll need to protect your main routine
code:

if __name__=="__main__":
p = MyProcess()
p.start()

This is documented in
17.2.3. Programming guidelines
17.2.3.2. Windows