iPhone:How to create thread running in the background always?

I want to initiate a separate thread apart from main thread and do some operations continuously even when my app is closed. I tried detachNewThreadSelector, but it doesn't work continuously and that too it needs my app to be launched.

And whenever I don't need it, I want to stop the thread as well. It is possible in Android, don't know how to do in iOS. How can I achieve it, could 开发者_运维问答someone guide me on this? I am developing on iOS 4.3 SDK.

You can't create a thread on a stock OS iOS device that will run in the background always. Some types of apps, such as for VOIP, audio play/record and GPS monitoring, can register for callbacks when the app is in the background.