c – 如何修复称为运行时错误的纯虚函数？

基类：

TailFileManager::TailFileManager(const std::string &filename,const int fileOpenPeriod_ms)
: m_Stop(false)
{
    m_WorkerThread.reset(new boost::thread(boost::bind(&TailFileManager::TailFile,this,filename,fileOpenPeriod_ms)));
}

TailFileManager::~TailFileManager()
{
    m_Stop = true;
    m_WorkerThread->join();
}

void TailFileManager::TailFile(const std::string &filename,const int fileOpenPeriod_ms)
{
    std::ifstream ifs(filename.c_str());

    while (! ifs.is_open())
    {
        boost::this_thread::sleep(boost::posix_time::milliseconds(fileOpenPeriod_ms));
    ifs.open(filename.c_str());
    }

    ifs.seekg(0,std::ios::end);

    while (! m_Stop)
    {
        ifs.clear();

        std::string line;

        while (std::getline(ifs,line))
        {
            OnLineAdded(line);
        }

        OnEndOfFile();
    }

    ifs.close();
}

派生类：

ETSLogTailFileManager::ETSLogTailFileManager(const std::string &filename,const int heartbeatPeriod_ms)
: TailFileManager(filename,heartbeatPeriod_ms),m_HeartbeatPeriod_ms(heartbeatPeriod_ms),m_FoundInboundMessage(false),m_TimeOfLastActivity(0)
{
}

ETSLogTailFileManager::~ETSLogTailFileManager()
{
}

void ETSLogTailFileManager::OnLineAdded(const std::string &line)
{
    // do stuff...
}

void ETSLogTailFileManager::OnEndOfFile()
{
    // do stuff...
}