> 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" _______________________________________________ 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
