Dear Fritz and all, I am reading one book, Daniel H Steinberg, Cocoa Programming, A Quick-Start Guide for Developers, 2010. Chapter 26 introduces Dispatch Queues. It mentions, "If you're writing an iPhone app or a desktop app that targets Leopard or earlier, you're out of luck."
Is GCD available when implementing an application on iPad/iPhone? Thanks so much! Bing On Mon, Apr 18, 2011 at 2:28 AM, Fritz Anderson <fri...@manoverboard.org>wrote: > On 17 Apr 2011, at 12:04 PM, Bing Li wrote: > > > I am programming on iPad. I notice that background applications are not > > allowed for power issues on iPad. I am not sure how to define the concept > of > > background applications? In my system, I need to have multiple threads > run > > when users interact with my system. The work done by the threads is the > > so-called background applications? If so, threading is not allowed? If > not, > > what do background application mean exactly? > > On iOS, an application is said to be in the background once the user has > tapped the Home button and returned to the home display (or has > double-tapped the Home button to expose the recent-app display and selected > another app). > > This usually means that the application is suspended, but preserved in > memory so it can resume when it comes back to the foreground. There are > exceptions, if it requests one: It can manage an audio stream or a VoIP > conversation; it can have the system monitor a VoIP control port or location > events; or it can simply ask for 10 minutes to execute while it is not > visible. In any case, if the system needs memory or processor resources for > the visible application, a background application may be terminated without > notice. > > iOS user applications may not fork/exec additional BSD processes. > > You seem to be talking about concurrency, in which a single application > uses threads to execute more than one independent task at the same time. iOS > supports threading, and offers several ways to do it: pthreads, NSOperation, > NSThread, and Grand Central Dispatch. Unless you have existing code that > uses another technology, Grand Central Dispatch is the recommended method. > > A mailing list isn't the place to go into depth. See the Concurrency > Programming Guide for an overview and pointers to details. < > http://developer.apple.com/library/ios/#documentation/General/Conceptual/ConcurrencyProgrammingGuide/Introduction/Introduction.html > > > > — F > > _______________________________________________ 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
