When first you learn about mutithreading, your head will be hurting for weeks.
If you share something don't touch it, let them handle it.
Because if you read its state it might have changed, if you write to it you don't know what else writes it. Unless you add synchronization around it with exclusive access. (and you're almost back at sequential code again, albeit with a lot more complexity)
Linux fueled mayhem & madness with a side of news, reviews, and whatever the Hell-Elks™ we come up with.