Getting Longitude/Latitude of the User When the viewDidLoad

My purpose is to get the longitude/latitude of the user when the view is loaded and to store the values in two variables for later calculations. I don't need to track the user location and to update it, I simply need to get his/her coordinates once. My code looks like this:

- (void)viewDidLoad {
    [super viewDidLoad];
    // locationManager update as location
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self; 
    locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
    locationManager.distanceFilter = kCLDistanceFilterNone; 
    [locationManager startUpdatingLocation];
    CLLocation *location = [locationManager location];
    // Configure the new event with information from the location
    CLLocationCoordinate2D coordinate = [location coordinate];

    float longitude=coordinate.longitude;
    float latitude=coordinate.latitude;

    NSLog(@"dLongitude : %f",longitude);
    NSLog(@"dLatitude : %f", latitude); 
}

In the console i keep getting this:

dLongitude : 0.000000
dLatitude : 0.000000

Can you please help me there?