On 19 Aug 2011, at 03:26, Nick Zitzmann wrote: > Short version: Have any of you ever used NSCache in a GC-enabled app? If so, > then how did you get the garbage collector to collect them? > > Long version: I have a framework that is used in a traditional retain-release > app and a different GC-enabled app. The framework creates NSCache objects for > storage of throw-away objects, and stores these NSCache objects in a > CFDictionaryRef. At some point, the CFDictionaryRef is instructed to remove > the entire cache when the app no longer needs that cache. > > That pops the NSCache and deallocates it in the retain-release app, but in > the GC app, I ran an Instruments test and found that the NSCache objects and > their contents were never being finalized. If I change the code so the code > uses NSMutableDictionary instead of NSCache, then the dictionaries and their > objects are properly finalized when popped. I want to use NSCache and not > NSMutableDictionary, but I can't do this in the GC-enabled app if the > collector is going to let the caches live forever. How do I make it so that > the collector collects them? > > I already tried using Instruments to monitor the GC object graph, but the > results made no sense. According to Instruments, the NSCache objects were > rooted by a non-object memory address created before main() was called, a > long time before the objects were made. Also, I noticed that objects in the > cache would not identify the cache as their root. (Is that normal?)
I don't use NSCache but I have used instruments to effectively debug GC memory collection problems. The described rooting behaviour of NSCache sounds peculiar to me. What happens if you call -removeAllObjects. Are the cached objects finalised correctly? I know this isn't the same as collecting the NSCache instance but at least, as a workaround if the issue persists, you can recycle the NSCache instances. Regards Jonathan Mitchell Developer Mugginsoft LLP http://www.mugginsoft.com_______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
