is +=1 thread safe

[Alexander Schmolck]

Gary Herron <gherron at islandtraining.com> writes:

> But... It's not!  
>
> A simple test shows that.   I've attached a tiny test program that shows this
> extremely clearly.  Please run it and watch it fail.

In [7]: run ~/tmp/t.py
final count: 2000000
  should be: 2000000

(I took the liberty to correct your test to actually do what I said, namely
use a numpy.array; just replace ``count = 0`` with ``import numpy; count =
numpy.array(0)``).


'as

p.s. please don't send me copies to on-list replies, at least not without
explicitly mentioning the fact -- I've got better things to do then guessing
whether something was meant to be off-list or not.