multiprocessing windows下运行

1.multiprocessing 非 __name__ == '__main__' windows下运行

import multiprocessing

def demo(a):
    print a
    time.sleep(10)

# 非 if __name__ == '__main__'  windows运行 
jobs = []
for i in range(2):
    p = multiprocessing.Process(target=demo, args=(1,))
    jobs.append(p)
    p.start()
    
for j in jobs:

    j.join()

# 结果 是电脑死机 崩溃 

2.如此运行，万事大吉

import multiprocessing
def demo(a):
    print a
    time.sleep(10)


def main():    
    jobs = []
    for i in range(2):
        p = multiprocessing.Process(target=demo, args=(1,))
        jobs.append(p)
        p.start()
        
    for j in jobs:
        j.join()
    
if __name__ == '__main__':
    main()