I might be misunderstanding, but doesn't this

> You can't possibly know instantly all the exceptions to handle for a function (given it calls other functions w/ exceptions), whereas, if it returns a fixed bunch of error codes, then you can know why that specific function failed and handle appropriately.

presume that, despite not being able to know all exceptions to handle in advance, you somehow have knowledge of all error conditions in the event that you're using error codes?