Create two threads in Objective-C
Use dispatch queues. They're essentially lightweight threads for which you don't need to worry about the threading or queueing directly.
-(void) spawn{ dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{ [self doWorkInBackground]; });}You can use one of the built-in queues or your own.
And you should probably read up on blocks too, in particular the memory management aspect.
- (void)performBlockInBackground:(void (^)())block { dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{ block(); });}Then you call it like this:
[self performBlockInBackground:^{ NSLog(@"Log from background");}];
This is a pretty deep discussion, but Apple's "Concurrency Programming Guide" should get you started.