Is the += operator thread-safe in Python?

Question

I want to create a non-thread-safe chunk of code for experimentation, and those are the functions that 2 threads are going to call.

c = 0

def increment():
          


        

Answer 1

Are you sure that the functions increment and decrement execute without any error?

I think it should raise an UnboundLocalError because you have to explicitly tell Python that you want to use the global variable named 'c'.

So change increment ( also decrement ) to the following:

def increment():
    global c
    c += 1

I think as is your code is thread unsafe. This article about thread synchronisation mechanisms in Python may be helpful.