Use extern variable through different controllers
===

I'm trying to make an app (using storyboard) and I want to populate it with events.
In my MapViewController.h I have:

    #imports
    
    extern NSMutableArray* events;
    
    @interface MapViewController : etc, etc{
    ..
    }

So what I want is to be able to import this .h file in, for example, my AppDelegate.m file and in there in appDidFinishLoading do stuff like:

    Event *event =  [[Event alloc] init];
    event.blabla = blabla;
    ...
    [events addObject:event];

and at the same time in my MapViewController.m I want a function that adds these events to my MKMapView (which is defined in my mapviewcontroller and called worldView)

so:

    @implementation MapViewController.m
    
    -(void)setEvents{
        for(int i = 0; i<[events count]; i++)
            [worldView addAnnotation:[events objectAtIndex:i]];
    }
    
    ...

As you might have guessed, it's failing during the linking part of the build with the following errors:

    Undefined symbols for architecture armv7:
    "_events", referenced from:
    -[AppDelegate applicationdidFini... ]
    -[MapViewController setEVents] in ...
    ..
    clang: error: linker command failed with exit code 1 (use -v to see invocation)


So.. Yeah.. Please help ^^ 
