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Caret no objetivo C
O que essa sintaxe ^ significa no Objective-

Estou cansado de pesquisar o significado do símbolo ^ no Objetivo C. Eu já o vi em muitos projetos, especialmente em tarefas de execução em segundo plano. Vou colocar um linkhttp: //developer.apple.com/library/ios/#samplecode/StitchedStreamPlayer/Introduction/Intro.html#//apple_ref/doc/uid/DTS4001009 e emMyStreamingMovieViewController.m você pode encontrar o seguinte dentro -(IBAction)endScrubbing:(id)sender method.

timeObserver = [[player addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(tolerance, NSEC_PER_SEC) queue:dispatch_get_main_queue() usingBlock:
                         ^(CMTime time)
                         {
                             [self syncScrubber];
                         }] retain];
    }

Além dissohttp: //developer.apple.com/library/ios/#documentation/iphone/conceptual/iphoneosprogrammingguide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.htm

- (void)applicationDidEnterBackground:(UIApplication *)application
{
UIApplication*    app = [UIApplication sharedApplication];

bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    // Clean up any unfinished task business by marking where you.
    // stopped or ending the task outright.
    [app endBackgroundTask:bgTask];
    bgTask = UIBackgroundTaskInvalid;
}];

// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

    // Do the work associated with the task, preferably in chunks.

    [app endBackgroundTask:bgTask];
    bgTask = UIBackgroundTaskInvalid;
});
}

Por favor, deixe-me saber a respost