Background queue block using GCD to create a thread for us

gistfile1.m

dispatch_queue_t mainQueue = dispatch_get_main_queue();
dispatch_queue_t backgroundQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    
    dispatch_async(backgroundQueue,^{
        
        // Do magical stuff in the background
        
        dispatch_async(mainQueue,^{
            
            // Update UI in the main thread
        });
    });