_citrus_region_offset
ret = _citrus_region_offset(&ms->ms_region, ms->ms_pos);
#define _region_offset _citrus_region_offset
_citrus_region_init(subr, _citrus_region_offset(r, ofs), sz);
return (*(uint8_t *)_citrus_region_offset(r, pos));
memcpy(&val, _citrus_region_offset(r, pos), (size_t)2);
memcpy(&val, _citrus_region_offset(r, pos), (size_t)4);