python - Lock in multiprocessing package not working -

the following code simple, testing purposes, not getting output desired:

from multiprocessing import process,lock  def printing(l,i):     l.acquire()     print     l.release()  if __name__ == '__main__':     lock = lock()      in range(10):         process(target=printing,args=(lock,i)).start() 

the output is:

0 1 2 3 5 6 4 7 8 9 

locks supposed suspend other processes executing. why isn't happening here?

what output did expect? output looks fine me: permutation of range(10). order in processes happen execute may vary run run. that's expected.

i suspect misunderstand lock does. when acquire lock, every other process trying acquire same lock blocks until lock released. that's all. in test run, process 0 happened acquire lock first. other processes trying acquire lock blocked until process 0 releases lock. process 0 prints 0 , releases lock. happened process 1 acquired lock. etc.

comment out l.release(), , you'll see program never finishes: first process happens acquire lock prints integer, , other processes forever blocked waiting acquire lock.