How can an iOS app run a function in the background in a recurring manner (i.e. once an hour)?

On devices which support multitasking, I'd like my iOS app to run a function in the 'background' when the app is not running (i.e. it's suspended). I know that iOS supports running tasks in开发者_Python百科 the background, but I'm not sure how to make the function recurring (and only when the app is not in the background). What's the best approach?

I'm not interested in running a long-term function in the background but a short-term function to simply update the application badge #. However this number is dynamically based on the app's data, and needs to run a query against core data.

To further clarify, yes, my core data will not be changing, but the badge represents a number of items due. As time progresses, more items will be due, so I want to update the badge to show the proper items due as time progresses. So if 5 items are due now, but half an hour later 3 more items are due, then by the time the next hour comes around, 8 items will be due even though the core data has not changed at all in and of itself.

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It can't, the only task allowed to run in background are: audio, voip and location.

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Why do you need to update the badge data every hour if the data stored within Core Data is not changing? ie. the app isn't running?

You can do this using push notifications, like previously posted, or you can use a scheduled local notification based on the data when the app is closed or backgrounded. I think those are pretty well your only options.