> On Aug 14, 2015, at 6:59 PM, Trygve Inda <cocoa...@xericdesign.com> wrote: > >> My main thread periodically downloads some data from a website. This is >> extracted into an NSArray (non-mutable) and placed in a property: >> >> @property (atomic, retain) NSArray* myArray; > >> NSString* someString = [[hostObject myArray] objectAtIndex:2]; >> >> How can I do this safely? >> >> The problem here is that if myArray is being replaced in the main thread >> after [hostObject myArray] is called but before objectAtIndex:2 is called, >> than myArray will disappear out from under the caller. > > One of the things that an atomic property's getter does, for an object pointer > type, is retain the object within the synchronization and autorelease it > before returning it. So, this is safe against that particular problem. The > returned array will remain valid within the caller's scope. >
That's good to hear. I couldn't find that documented anywhere. This seems like the best solution - and the only place I have ever needed to use an atomic property. I can't think of a better way to do this sort of thing other than the Core Data technique I mentioned in the original post. Thanks, Trygve _______________________________________________ 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
