Yielding in this context means to a different “thread” in your context, not the OS. If you want to express “this is a point where the program can do something e

Yielding in this context means to a different “thread” in your context, not the OS. If you want to express “this is a point where the program can do something else” it is a yield. If you block and can’t switch to something else… it is not. So if you’re using an API like mmap like that you should think of it as IO (I don’t think you can, but am not sure).