OK, I see and if don't want l to exist in f() I have to:

def f():
   pass

def a():
   l=[]
   f()

a()

????

Jurek

Martin v. Löwis wrote:
> Martin v. Löwis <martin@v.loewis.de> added the comment:
> 
>> I still do not understand what is going on when python executed thic 
>> code. I have a local variable l in my parent process. 
> 
> No, you don't. It's a global variable, not a local one.
> 
>> When I create a 
>> child process, program makes first makes a copy of memory. Than what?
> 
> It doesn't have to do anything with the multiprocessing at all.
> For comparison, just run the Python script
> 
> def f():
>   del l
> l = []
> f()
> 
> It produces the same error, with no multiprocessing involved.
> 
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue5092>
> _______________________________________
> 
> 
>