> On Aug 27, 2016, at 8:22 AM, じょいすじょん <dangerwillrobinsondan...@gmail.com> > wrote: > > >> On 2016 Aug 27, at 23:09, Keary Suska <cocoa-...@esoteritech.com> wrote: >> >>> >>> On Aug 27, 2016, at 5:22 AM, Andreas Falkenhahn <andr...@falkenhahn.com> >>> wrote: >>> >>> Consider the following example properties: >>> >>> NSApplication: @property(strong) NSMenu *mainMenu >>> NSFont: @property(readonly, copy) NSString *familyName >>> NSColorPanel: @property(copy) NSColor *color >>> >>> AFAIU I must not release the NSMenu/NSString/NSColor obtained from these >>> properties because I don't own the objects returned by those properties and >>> Apple's memory management policy docs clearly say: >>> >>> "You must not relinquish ownership of an object you do not own" >>> >>> So I think I've got that right but I'd be glad if somebody could just >>> confirm that I got it right ;) >>> >>> I'm just a little confused because of the keywords "strong" and "copy" in >>> the @property declarations but AFAIU these only refer to setting those >>> properties, not getting those properties, i.e. the object is copied when >>> *setting* the property, not when *getting* it. Right? >>> >>> And another question: Can it also happen that a class has a property >>> which returns an object which I *must* release or is it a general rule >>> that getting a @property always returns objects which I do not own >>> and hence mustn't released? >> >> There are only specific method conventions that establish ownership: >> alloc+init and new. This is because ownership should only be granted when >> specifically requested by the caller. There is no good reason for an object >> to require that a caller own a returned object. Now, some API could decide >> to buck the convention and have a different object construction naming, but >> the point is the same. If an API does anything else, it is badly designed. >> Cocoa will never do this. >> >> One could even argue (and some have) that there is no good reason for *any* >> object method to return a retained object, as that forces the caller to >> explicitly require ownership. And that is key: ownership is a function of >> the caller, not the object. >> >> HTH, >> >> Keary Suska >> Esoteritech, Inc. >> "Demystifying technology for your home or business" >> >> > Just to keep everyone on the rules, I'm going to post the docs links. > It's too easy to quote it wrong. (not saying anybody did) > > Objective-C > > https://developer.apple.com/library/mac/documentation/General/Conceptual/DevPedia-CocoaCore/MemoryManagement.html > > https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/MemoryMgmt.html > > Core Foundation (because you WILL use it at some point) > > https://developer.apple.com/library/mac/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html
Doh! Forgot “copy”. Best to point to docs since they are clear and succinct. Keary Suska Esoteritech, Inc. "Demystifying technology for your home or business" _______________________________________________ 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
