atomic operations in presence of multithreading

[Duncan Booth]

Paul Moore <pf_moore at yahoo.co.uk> wrote in news:y8l55cwa.fsf at yahoo.co.uk:

> Given that the original question was about dictionaries, which are
> coded in C (and so not subject to this issue) there is still the
> following case: when the old value stored in the dictionary is
> replaced, that could be the last reference to it. When the old value
> is freed, its __del__ method gets called - arbitrary Python code
> again.

Right, but the new value has already been stored in the dictionary at the 
point where the __del__ method is called, so as far as the OP is concerned 
this is still safe.