Question

Simple question: what happens if I do this:

- (void)viewDidLoad
{
    [self performSelectorInBackground:@selector(myBGMethod) withObject:nil];
}

-(void)myBGMethod
{
    [self myOtherMethod];
}

-(void)myOtherMethod
{
    NSLog(@"This is not Inception");
    //some more code here
}

Will the NSLog() and other code in myOtherMethod be run on the main thread or in the background?

Answer 1

It’ll be run in the background thread.

You can confirm this by calling NSLog inside all your methods. By default, NSLog prints the thread number along the process ID (pid).