Strings in Cocoa: Part I
Subject:   Comparing @"..." type NSStrings
Date:   2001-07-07 00:47:41
From:   halliday
Response to: Comparing @"..." type NSStrings

As the NSString documentation indicates (in it's Objective-C version): "The compiler makes such object constants unique on a per-module basis".

Some of the features that rely upon this behavior are Pasteboard Types (they are really @"..." type NSStrings), various Attribute Keys, Exceptions, and Notifications (to name a few). Of course, this is an implementation detail, and is always subject to change.