On May 26, 2015, at 1:00 PM, Fritz Anderson wrote: > > On 22 May 2015, at 7:49 AM, Alex Zavatone <z...@mac.com> wrote: > >> @property (nonatomic, strong) NSString *thing; >> > > Another chore in porting this code: The retention attribute should be copy, > not strong.
I just typed that off the top of my head, BUT now that you mention it, I'm really happy you pointed it out. For any nonmutable class, should I be using copy instead of strong or is this just with NSString? > If you needed to track changes in the string, you'd use strong, but NSStrings > don’t mutate; NSMutableStrings do. > > If you do assign a mutable string into the NSString property, the non-mutable > class promises the users of your API that it won’t mutate. You need a copy to > prevent changes behind your back. The performance hit is the price you pay to > prevent a bug. > > copy is not a performance issue for NSString. It doesn’t copy anything, it > just increments the retain count and returns the same pointer. (Static/global > NSStrings don’t even bother to deallocate themselves.) Copying a mutable > string does allocate and initialize a new object; either way, the attribute > does the Right Thing. > Thanks. This is stuff that my brain didn't have room for when deciphering what our classes were actually doing. Best, Alex Zavatone _______________________________________________ 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
