This code produces: "'jobs::abbrev' cannot appear in a constant-expression" and "note: in expansion of macro 'HIBERLITE_NVP'"

timeclock.cpp

class jobs
// Jobs table in timesheet.db
{
  friend class hiberlite::access;
  template<class Archive>
  void hibernate(Archive & ar)
  {
    ar & HIBERLITE_NVP(id);
    ar & HIBERLITE_NVP(uuid);
    ar & HIBERLITE_NVP(name);
    ar & HIBERLITE_NVP(abbrev);
    ar & HIBERLITE_NVP(pay);
    ar & HIBERLITE_NVP(worked);
  }
  public:
    int id;
    char uuid;
    char name;
    char abbrev;
    float pay;
    time_t worked;
};