One approach I have seen people take in Objective C (and Scala) is to return a Maybe "monad" from functions instead of the value directly - forces the caller to match for cases when the actual value comes back versus the "non value".
Are you sure you're thinking about Objective-C? Objective-C lets you send messages to nil/0 which then return nil/0 silently - a feature used quite often in all Objective-C code I've been exposed to and written myself in the 2 years I've been doing it.
