When to use custom exceptions vs. existing exceptions vs. generic exceptions

Question

I\'m trying to figure out what the correct form of exceptions to throw would be for a library I am writing. One example of what I need to handle is logging a user in to a st

Answer 1

I think you need to have one base exception and one subtype exception for each of the situalitions you describe (actually you can make db down and internal db error to have the same base exception). The key point is that it is good practice to have your own exceptions for your library.