c# - When is it appropriate to use error codes?

Question

In languages that support exception objects (Java, C#), when is it appropriate to use error codes? Is the use of error codes ever appropriate in typical enterprise applications?

Many well-known software systems employ error codes (and a corresponding error code reference). Some examples include operating systems (Windows), databases (Oracle, DB2), and middle-ware products (WebLogic, WebSphere). What benefits do error codes provide? What are the disadvantages to using error codes?

Answer 1

WITHIN a program one should always use exceptions instead of error codes. However, exceptions can't propagate beyond a program. Any time the error must leave the program you are left with error messages or error codes.

For simple things that will always be human-operated error messages without codes are fine. You can say "File not found" without giving it an error code. However, if it might be another computer on the other end then you should give error codes in addition. You don't want to break the other system when you change it to "File <x> not found".