C++ logger class excerpt

logger.cpp

Logger * Logger::m_Instance = 0;

Logger::Logger() {
  char* buf = nullptr;
  size_t sz = 0, l = 0;
  // No `m_Instance` declared here
  
  Logger * Logger::getInstance() throw () {
    if (m_Instance == 0) {
      m_Instance = new Logger();
    }
    return m_Instance;
  }
}

logger.h

class Logger {
  public:
    static Logger * getInstance() throw ();
  private:
    static Logger * m_Instance;
};