gistfile1.m

//
//  ExternalViewController.m
//
//  Created by William LaFrance.
//  Public Domain
//

#import "ExternalViewController.h"

@interface ExternalViewController ()

@property (strong, nonatomic) UIWindow *externalWindow;

@end

@implementation ExternalViewController

@synthesize externalWindow = _externalWindow;

- (id)init
{
    self = [super init];
    if (self) {
        NSAssert([UIScreen screens].count > 1, @"No external display");
        self.externalWindow = [[UIWindow alloc] init];
        self.externalWindow.screen = [[UIScreen screens] lastObject];
        self.externalWindow.rootViewController = self;
        [self.externalWindow makeKeyAndVisible];
    }
    return self;
}

@end