On 28/01/2010, at 3:37 AM, Scott Ribe wrote: > Of course this code does not necessarily *prevent* you from making multiple > Debug instances, but neither does the code Graham posted if you try to call > [Debug sharedDebug] from multiple threads.
Calling a singleton method from multiple threads does not make multiple instances. It returns the same shared instance regardless (the 'static' keyword does not create thread local storage*). In fact that might be cause for concern if you are using it from multiple threads - you need to design the class itself to be thread-safe. If you do want multiple instances, a simple alloc/init when needed is all you need to do, but if you truly want to enforce a single instance under all possible conditions, you'd need to override -init and -copyWithZone: and probably others to always return the singleton. *GCC supports thread-local storage using the __thread keyword. Use that instead of 'static' and you will get a separate instance per thread, though as a GCC feature not a language feature the code is less portable. --Graham _______________________________________________ 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
