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Trying to use threading.local()


On 14-09-18 10:29, Chris Angelico wrote:
> On Fri, Sep 14, 2018 at 5:25 PM, Antoon Pardon <antoon.pardon at vub.be> wrote:
>>
>> ... Suppose I have two threads, one in which I need
>> a precision of 3 and the other in which I need a precision of 7. In what
>> circumstances is it needed to use threads-locals to accomplish this and
>> how do I accomplish this?
>>
>> If I want my decimal code be usable with threads, how should I write it?
> Let's say both of those threads call the same function, which does this:
>
> def f(x, y):
>     return x * 3 + y / 4
>
> You can't pass a context as a parameter, so you have to set the
> context externally. Which is done thus:
>
> https://docs.python.org/3/library/decimal.html#decimal.setcontext
>
> Note that this sets it *for the current thread*.

So, if I understand correctly, the threads-local information in this case is
part of the decimal implementation, so that the right context/precision is
used for the right thread.

-- 
Antoon Pardon.