On Oct 26, 2010, at 15:47:09, Greg Parker wrote: > On Oct 26, 2010, at 2:33 PM, Rick Mann wrote: >> Sure seems like a conceptual inconsistency, but I guess whoever designed the >> language thought it was too expensive to return a zeroed struct. > > It's an artifact of C compatibility. On each architecture, Objective-C > messages follow the same parameter-passing rules as C function calls. On all > modern architectures, the rules for returning a struct mean that > objc_msgSend() has no way to know how big the returned struct is supposed to > be, so it can't zero it. > > A few years ago we prototyped a compiler that added the nil check at the call > site instead. Doing that everywhere was too expensive in terms of code size, > but doing it for structs only might be practical.
Fair 'nough. That makes sense. -- Rick _______________________________________________ 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
