How do I get the error message in Swift 2.0?

Use automatic error variable, and you can cast it to NSError if you wish:

catch {    let nsError = error as NSError    print(nsError.localizedDescription)}

You can now throw any object inheriting ErrorType, and provide custom handling in the catch sentence. You can also cast the error to NSError to access localizedDescription for handling third party errors.

Casting an enum ErrorType will produce a NSError with domain equal to the enum name, code equal to the enum value and an auto-generated localizedDescription with the following format:

The operation couldn’t be completed. (DOMAIN error CODE.)

For example, the following code:

enum AwfulError: ErrorType {    case Bad    case Worse    case Terrible}func throwingFunction() throws {    throw AwfulError.Worse}do {    try throwingFunction()}catch AwfulError.Bad {    print("Bad error")}catch let error as NSError {    print(error.localizedDescription)}

Will print

The operation couldn’t be completed. (AwfulError error 1.)

Despite the question title specifying Swift 2, this answer is for Swift 3.

As @redent84 points out, since Swift 2 an Error object may be a home-made one. Here's a method I wrote to analyze and print the default error object available in a "catch" statement that doesn't specify any specific error type:

   // Method to print an unknown Error type object to the system output.   static func printCaughtError(_ unknownError : Error) {      let objectDescription = String(describing: unknownError)      let localizedDescription = unknownError.localizedDescription      if localizedDescription != "" {         if localizedDescription.contains(objectDescription) {            print(localizedDescription)            return         }         if !objectDescription.contains(localizedDescription) {            print(objectDescription + ": " + localizedDescription)            return         }      }      print(objectDescription)   }

Then you can call it like this:

    catch {       printCaughtError(error)    }