iOS : include audio files in an app, in its sandbox directory

So I tried a basic text loading example. I found that I could reach the enclosed file by invocating the following path : (compiled for OSX)
myFile = File::getSpecialLocation (File::currentApplicationFile).getChildFile (String(“Contents/Resources/truc.txt”));
… BUT for iOS I still can not get the file :
myFile = File::getSpecialLocation (File::currentApplicationFile).getChildFile (String(“truc.txt”));

I saw also the following post which is interesting as well, but not yet the answer :