Possible Duplicate:
How to deploy to Snow Leopard with ARC enabled
Quoting from Hillegas Book on Cocoa Programming for Max OS X from the memory management chapter
The new solution, introduced in Mac OS 10.7 and iOS 5, is automatic reference counting, more commonly known as ARC. ARC relies on the original retain-count mechanism but with a twist: The compiler manages the bookkeeping of retain counts for you.
I am writing a Max OS X application that has to be compatible with 10.5 and onwards till 10.8. So my understadnig based on the above is that if ARC was introduced in 10.7 does it mean that if I build my application on a platform 10.7 with ARC, the app won’t be able to run on 10.5 and 10.6 ? because ARC feature was introduced in 10.7
What memory management should I use if the app has to be compatible with 10.5/6/7/8
Also it might be important to tell, my backend is mostly in C++ (and I know I have to manage C++ memory myself and not relying on ARC) and front end in Objective-C
My development platform is 10.7 Lion / Xcode 4.3
Senior please shed some light.
Edit
From the comments I understand that ARC is depndent on runtime support as well, which essentially means it is not suitable in my case. Also it is not supported on 10.5 anyways, so should I do manual memory management ?
I would choose MRR.
No portion of ARC is available on OS X versions prior to 10.6. Zeroing weak references requires 10.7.
See the Apple ARC availability matrix here.