docs: function readFileSync (fileName, options) {
      verifyFileName (fileName);
  
      var info = getFileInfo (fileName);
      if (info.exists === false) {
          var message1 = format (cc.MSG_DOES_NOT_EXIST, fileName);
          throw new SafeFileError (cc.DOES_NOT_EXIST, message1);
      }
      if (info.isFile === false) {
          var message2 = format (cc.MSG_IS_NOT_A_FILE, fileName);
          throw new SafeFileError (cc.IS_NOT_A_FILE, message2);
      }
  
      // read data file
      var data = null;
      try {
          data = fs.readFileSync (fileName, options);
      } catch (e) {
          var message3 = format (cc.MSG_READ_ERROR, fileName, e.message);
          throw new SafeFileError (cc.READ_ERROR, message3);
      }
  
      // return data
      return (data);
  }