macOS Basic Cocoa with bindings question

[rebo]

Just confused here is there any reason why


_properties = [NSMutableDictionary dictionaryWithObjects:values forKeys:keys];


Causes a crash, where


_properties = [[NSMutableDictionary alloc] initWithObjects:values forKeys:keys];


works fine in an application with bindings?

Thanks, I'm sure this is a very simple thing i'm missing!

 

[HiRez]

The first one is autoreleased, so if you don't retain it after creating it, it'll be invalid sometime after method you created it in goes out of scope (you can't tell exactly when, it's whenever the event loop cycles and the runtime drains the autorelease pool). When bindings tries to use it, crash, because it no longer exists.

The second one has a retain count of one because you used alloc, and will not be automatically released. Hence, no crash. You should be sending this object a release at some point in the future (probably in your dealloc method).

You didn't say if you're using garbage collection memory management or not...

 

[rebo]

Thank you very much HiRez, that explains it!

No not using Garbage collection memory management right now, still pretty new at cocoa programming!

 

[lee1210]

I guess I'll be the one to be a stickler and say that this is an Objective-C memory management issue, not really a Cocoa issue. There is a Cocoa convention at work in terms of the naming of methods, but autorelease pool issues, retain/release issues etc. are all Objective-C language features.

-Lee