How to make an array that is thread safe?

[Petz]

I have an array that can be accessed and modified by multiple players at the same time.
How to make that tread safe?
Array is a member of a particular class that implements function that is being called by players.

[djpixel]

It depends.

The documentation says that anything that does not use <suspends> is already atomic (even when it runs in parallel with other code).

Immediate expressions stick together on their own. All adjacent immediate (non-async) expressions are considered to be atomic — their code is guaranteed to run without interruption within the same update, and without preemption or context switching. It is as though such code had an automatic mutual-exclusion primitive wrapped around them.

Let’s take this code that tries to avoid duplicates:

if (not Array.Find[Value]):
    set Array += array { Value }

In Verse this not need extra safety (such as locks) that it would need in other languages.

If you do suspend, that’s no longer true:

if (not Array.Find[Value]):
    Sleep(0.0)
    set Array += array { Value }

However there is no general answer: it will depend on your code structure, and array operations you need to do.

For example, in the above scenario you could check Find again after sleeping.

[Petz]

Thanks, this is answer I was looking for.
Can you please just point me where in documentation did you find this?

[djpixel]

Sure: please see Concurrency Overview.