Question

The title says everything!

In Objective-C, what’s the difference between self.propertyName vs. propertyName?

Answer 1

self.propertyName increse the retain count by one if you have specified the propertyName as retain in property declaration

propertyName will not increase the retain count an could lead to the crash of application.

e. g. ,

@property (nonatomic,retain) NSString* propertyName;

lets say you have nameProperty NSString object.
Below increase the retain count by 1 and you could use self.propertyName and call release.

self.propertyName = nameProperty;
[nameProperty release];

Below does’nt increase the retain count so if you use propertyName in your application it will result in crashing of your application.

propertyName = nameProperty;
[nameProperty release]; 

Any further use of propertyName will result in crash.