On Sat, Feb 14, 2009 at 1:49 AM, Jacob Rhoden <li...@jacobrhoden.com> wrote: > Hi Guys, > > I have been starting to use NSOperationQueue. I have ended up with one put > in each controller (ie see below), but now I have one in too many > controllers. How does it work? Should I just have one global variable for > the operation queue, or do multiple NSOperationQueue's "share" the same > resources?
Yes, they all share the background worker threads that they use. The incremental resource usage from having multiple NSOperationQueues in your application is minimal. The only reason to have one versus many is that you can control individual queues, for example by limiting the number of simultaneous operations, or suspending/canceling/waiting for the operations in the queue. Unfortunately this resource sharing is buggy: http://www.mikeash.com/?page=pyblog/dont-use-nsoperationqueue.html If you read all the way to the end you'll see that NSOperationQueue can be induced to crash even when using only *one* queue in the entire program, so you can't save yourself by sharing a single global queue as was once thought. The bug manifests rarely enough that it can be useful for experimentation but I would not plan to ship any code until the bug is fixed. This may mean waiting for a Leopard point release or it may, in the worst case, mean requiring Snow Leopard for your program. If you plan to ship code in the near future I recommend avoiding NSOperationQueue completely. Mike _______________________________________________ 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
