GCD Is Available On iPhone/iPad
GCD Is Available On iPhone/iPad
- Subject: GCD Is Available On iPhone/iPad
- From: Bing Li <email@hidden>
- Date: Thu, 05 May 2011 22:44:32 +0800
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 <email@hidden>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
>
>
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