RH_HOLD_SNAPLVL
#define HANDLE_HOLD_SNAPLVL(h) HOLD_HANDLE((h), RH_HOLD_SNAPLVL, rh_snaplvl)
#define HANDLE_RELE_SNAPLVL(h) RELE_HANDLE((h), RH_HOLD_SNAPLVL)
held = RH_HOLD_SNAPLVL;