iphone ios running in separate thread

In my opinion, the best way is with libdispatch, aka Grand Central Dispatch (GCD). It limits you to iOS 4 and greater, but it's just so simple and easy to use. The code to do some processing on a background thread and then do something with the results in the main run loop is incredibly easy and compact:

dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{    // Add code here to do background processing    //    //    dispatch_async( dispatch_get_main_queue(), ^{        // Add code here to update the UI/send notifications based on the        // results of the background processing    });});

If you haven't done so already, check out the videos from WWDC 2010 on libdispatch/GCD/blocks.

The best way for the multithreading in iOS is using GCD (Grand Central Dispatch).

//creates a queue.dispatch_queue_t myQueue = dispatch_queue_create("unique_queue_name", NULL);dispatch_async(myQueue, ^{    //stuffs to do in background thread    dispatch_async(dispatch_get_main_queue(), ^{    //stuffs to do in foreground thread, mostly UI updates    });});

I would try all the techniques people have posted and see which is the fastest, but I think this is the best way to do it.

[self performSelectorInBackground:@selector(BackgroundMethod) withObject:nil];