Expression must have constant value.

  bool readPacket(const FileStreamPtr& fin){
    try{
        if (!fin){
          stdext::throw_exception("Error: FileStreamPtr not found");
          return false;
        }

        uint8_t packetCode = fin->getU8();
        if (packetCode != 255){
          stdext::throw_exception(stdext::format("Error: FileStreamPtr packetCode = %d", packetCode));
          return false;
        }

        id = fin->getU32();
        time = fin->getU32();
        int16_t msgSize = fin->getU16();
        uint8 data[msgSize];
        fin->read(&data[0], msgSize);
        msg = OutputMessagePtr(new OutputMessage);
        msg->addBuffer(msgSize, &data[0]);


    }catch(stdext::exception& e) {
      g_logger.error(stdext::format("Error in readFrame: %s", e.what()));
      return false;
    }

    return true;
  }

  OutputMessagePtr getMsg() { return msg; }
  uint32_t getTime() { return time; }
  uint32_t getId() { return id; }

  OutputMessagePtr msg;
  uint32_t time = 0;
  uint32_t id = 0;
};

uint8 data[msgSize];

Expression must have a constant value.