macOS Silly property question

[ace2600]

Hi,

Given something like

@interface ExampleClass : NSObject {
    NSObject *prop;
}

@property (nonatomic,retain) NSObject *prop;

If I access prop within ExampleClass am I accessing it as a property (using the property getters and setters) or am I accessing the variable directly? If directly, do I need to call self.prop to access using the property getters/setters/etc.?

Also, does anyone know of links to good examples on retain vs assign. I've read a few articles, but I feel example situations on when you'd use one over the other would be helpful.

 

[tacoman667]

Hi,

Given something like

@interface ExampleClass : NSObject {
    NSObject *prop;
}

@property (nonatomic,retain) NSObject *prop;

If I access prop within ExampleClass am I accessing it as a property (using the property getters and setters) or am I accessing the variable directly? If directly, do I need to call self.prop to access using the property getters/setters/etc.?

Also, does anyone know of links to good examples on retain vs assign. I've read a few articles, but I feel example situations on when you'd use one over the other would be helpful.

In my book it says that in Obj-C 2.0 garbage collection, retain and assign have no real difference because the GC will pick em up automatically. If I recall though.

The book also says that if you are using the property to instantiate auto getters/setters then you would need to use "dot" notation, for eaxample use self.property over [property doesSomething].

 

[therevolution]

If I access prop within ExampleClass am I accessing it as a property (using the property getters and setters) or am I accessing the variable directly? If directly, do I need to call self.prop to access using the property getters/setters/etc.?

Yes, access to prop would be direct. self.prop would use the getter/setter methods.

Also, does anyone know of links to good examples on retain vs assign. I've read a few articles, but I feel example situations on when you'd use one over the other would be helpful.

I don't know of any resources, no. But if you understand what retain means, and where you should and shouldn't use it, it's not too hard. If you don't know how/when to use retain, definitely learn it ASAP. It's pretty fundamental.

I would say as a rule of thumb, you're going to want to retain anything that inherits from NSObject. You'd use assign for primitives, like int, float, BOOL, and also for things like structs.

 

[tacoman667]

(...) retain anything that inherits from NSObject (...) You'd use assign for primitives, like int, float, BOOL, and also for things like structs.

*SMACKHEAD* Duh. I forgot about that till I read your post.

 

[ace2600]

Thanks for the help!

self.prop = nil has the same affect as [prop release]? If so, is there a preference on the best way to deallocate the variable?

 

[Catfish_Man]

Thanks for the help!

self.prop = nil has the same affect as [prop release]? If so, is there a preference on the best way to deallocate the variable?

Interesting question I would try it and see. Something like

NSLog(@"Retain count is: %d", [self.prop retainCount]);
self.prop = nil;
NSLog(@"Retain count is: %d", [self.prop retainCount]);