Now that multicore processors are coming to mobile devices, wouldn't it be great to take advantage of all those cores without having to manage threads? This concise book shows you how to use Apple's Grand Central Dispatch (GCD) to simplify programming on multicore iOS devices and Mac OS X.Managing your application's resources on more than one core isn't easy, but it's vital. Apps that use only one core in a multicore environment will slow to a crawl. If you know how to program with Cocoa or Cocoa Touch, this guide will get you started with GCD right away, with many examples to help you write high-performing multithreaded apps.Package your code as block objects and invoke them with GCDUnderstand dispatch queues--the pools of threads managed by GCDUse different methods for executing UI and non-UI tasksCreate a group of tasks that GCD can run all at onceInstruct GCD to execute tasks only once or after a delayDiscover how to construct your own dispatch queues