Objective-C Programming (2nd Edition)   27. Callbacks

About the 27. Callbacks category (1)
Passing a function as an argument? (4)
Confusion on Callbacks and objects ownership (1)
NSTmer *t not used in updateLastTime (5)
NSURLconnection deprecated, how to use NSURLsession? (3)
Problem with NSTimer (3)
Unused (4)
Shouldn't this be private? (2)
Confused about missing declaration of zoneChange in logger.h (17)
Dot operator question (3)
Confused about static modifier with pointer (7)
NSURLConnection Delegate - how does it know which methods? (4)
Bad Url in Helper Objects (2)
Gutenberg 404 (3)
Explanation as to why notification is used (4)
How to know which protocol to use? (1)
How to create block for addObserverForName:object:queue:usin (2)
Explaining this method in documentation (6)