Yes like errno, except not global of course, you add one per struct/context/module/thread/whatever.
And you design the functions to early return if the error state is set.
>how do you know which call introduced the error first?
You rarely care about that but if you do you either make the error state stick to the first error, or as I said, make it a list you can append multiple errors to.
>how do you know which call introduced the error first?
You rarely care about that but if you do you either make the error state stick to the first error, or as I said, make it a list you can append multiple errors to.