Are the HTTP status codes defined anywhere in the iOS SDK?
Well, they are defined in the sense that
[NSHTTPURLResponse localizedStringForStatusCode:(NSInteger)statusCode]
can return a string for the given status code. Is that what you are looking for?
I did a
grep -r '404' *
in
/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk/System/Library/Frameworks/
and came up empty handed so the answer is almost certainly "no".