c->vftbl->subtype_display[i] = NULL;
c->vftbl->subtype_offset = OFFSET(vftbl_t, subtype_display[0]) + sizeof(vftbl_t*) * depth_fixed;
c->vftbl->subtype_depth = depth;
c->vftbl->subtype_display[i] = NULL;
c->vftbl->subtype_offset = OFFSET(vftbl_t, subtype_display[0]) + sizeof(vftbl_t*) * depth_fixed;
c->vftbl->subtype_depth = depth;