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POHow to receive notifications posted via CPDistributedNotificationCenter
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  1. POHow to receive notifications posted via CPDistributedNotificationCenter
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    copied!<p>The private <code>AppSupport</code> framework on iOS has a class called <code>CPDistributedNotificationCenter</code> which appears to support a subset of the functionality provided by <code>NSDistributedNotificationCenter</code> on OS X.</p> <p>I'm attempting to use this class to post notifications from a background daemon such that multiple clients in other processes can receive these notifications and act on them. I realize there are other options, including <code>CPDistributedMessagingCenter</code> or <code>CFMessagePort</code>, low level mach ports or even darwin's <code>notify_post</code>. I'd prefer it if the daemon had no knowledge of the clients however, and I'd like to be able to pass data along with the notification, and <code>notify_post</code> does not allow this.</p> <p>Currently, this is what I am doing in the daemon:</p> <pre><code>CPDistributedNotificationCenter* center; center = [CPDistributedNotificationCenter centerNamed:@"com.yfrancis.notiftest"]; [center runServer]; [center postNotificationName:@"hello"]; </code></pre> <p>And in the client:</p> <pre><code>CPDistributedNotificationCenter* center; center = [CPDistributedNotificationCenter centerNamed:@"com.yfrancis.notiftest"]; [center startDeliveringNotificationsToMainThread]; NSNotificationCenter* nc = [NSNotificationCenter defaultCenter]; [nc addObserver:[Listener new] selector:@selector(gotNotification:) name:@"hello" object:nil]; </code></pre> <p>where <code>Listener</code> is a simple class that implements a single method <code>gotNotification:</code> </p> <p>Unfortunately, the client never receives the 'hello' notification. If I replace the <code>name</code> argument in the <code>addObserver</code> call with <code>nil</code> I can see every notification delivered to the client's notification center, but 'hello' is not one of them.</p> <p>I got the inspiration for my code by looking at a disassembly of <code>SpringBoard</code> and <code>CPDistributedNotificationCenter</code>. Notifications appear to be delivered via <code>CPDistributedNotificationCenter</code>'s <code>deliverNotification:userInfo:</code> which acts as a shim for <code>NSNotificationCenter</code>'s <code>postNotificationName:object:userInfo:</code>.</p> <p>What am I missing here?</p>
 

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