Cocos2d-x sound effect while letting user's song playing in iOS

cocos2d-x_let_song_play.m

// AppController.mm

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 
  [[CDAudioManager sharedManager] setMode:kAMM_FxPlusMusicIfNoOtherAudio];

  return YES;
}

// in other file

#include "audio/include/SimpleAudioEngine.h"

void SomeClass::someMethod() {  
  CocosDenshion::SimpleAudioEngine::getInstance()->playEffect("res/sfx.mp3");
}