gistfile1.txt

PFQuery *query = [PFUser query];
    [query whereKey:@"position" nearGeoPoint:position];
    query.limit = 20;
    
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            for (PFObject *object in objects) {
                NSLog(@"%@", object[@"username"]);
            }
        } else {
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];