Den 23:10 6. mars 2012 skrev Marco Tabini <mtab...@me.com> følgende: > On 2012-03-06, at 2:51 PM, Jan E. Schotsman wrote: > >> Hello, >> >> I have an array of progress values (number objects) for subprojects, from >> which I calculate the overall progress . >> The array is an atomic property of the project class. >> >> Is it safe to access this array from multiple threads, using methods like >> objectAtIndex and replaceObjectAtIndex? >> > > NSMutableArray is not (as far as I know) thread-safe while being mutated[1]. > That said, it doesn't mean that you can't use the array in a multi-threaded > environment: Just make sure that writes are all synchronized, and that > enumerations only happen on immutable copies. > > HTH,
Perhaps OP thought that just declaring the array as an atomic property would make it thread-safe. I believe this would happen if getters/setters were synthesized, and the array contents was only changed by creating a whole new array, and always replacing it using the setter. You would typically make the array immutable for such an approach. In general, this can be a decent way of doing things in a multithreaded app, because time spent in synchronized code would be minimized. But I don't know if there are Cocoa-specific reasons to avoid it, and of course it depends on how feasible it is for the application. Per _______________________________________________ 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
