Where is the DEBUG macro defined?

Question

When I run code such as the following:

- (void)viewDidLoad
{

#ifdef DEBUG
    NSLog(@"debug");
#else
    NSLog(@"here");
#endif
    [super viewDidLoad];
}

I see "debug" printed in the log, but I did not define DEBUG explicitly. Where is it defined?

Answer 1

It is most likely defined in your Build Settings under Preprocessor Macros.

Here is an example from one of my projects