I was working the following example from Doug Hellmann tutorial on multiprocessing:

import multiprocessing

def worker():
    """worker function"""
    print 'Worker'
    return

if __name__ == '__main__':
    jobs = []
    for i in range(5):
        p = multiprocessing.Process(target=worker)
        jobs.append(p)
        p.start()

When I tried to run it outside the if statement:

import multiprocessing

def worker():
    """worker function"""
    print 'Worker'

jobs = []
for i in range(5):
    p = multiprocessing.Process(target=worker)
    jobs.append(p)
    p.start()

It started spawning processes non-stop, without any way of to terminating it. Why would that happen? Why it did not generate 5 processes and exit? Why do I need the if statement?