simple 单例

Message* Message::m_pInstance = ;//类外初始

Message::Message()
{

}

Message::~Message()
{
    if (m_pInstance != )
    {
        delete InstanceServer::m_pInstance;
        m_pInstance = ;
    }
}

Message*Message::getInstance()
{
    if (m_pInstance == )
    {
        m_pInstance = new Message();
    }
    return m_pInstance;
}

void Message::deleteInstance()
{
    if (m_pInstance != nullptr)
    {
        delete m_pInstance;
        m_pInstance = nullptr;
    }
}