facebook login ios sdk v2.3

    FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];
    [login logInWithReadPermissions:@[@"email"] handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) {

        if (error) {
            NSLog(@"Error %@", error);
        } else if (result.isCancelled) {
            NSLog(@"user cancel %@", result);
        } else {
            if ([result.grantedPermissions containsObject:@"email"]) {
                NSLog(@"email");
            }
        }
    }];