MF_TRY0NULL
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY0NULL;
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
if (bitset(MF_TRY0NULL, map->map_mflags))
map->map_mflags &= ~MF_TRY0NULL;
map->map_mflags &= ~MF_TRY0NULL;
if (bitset(MF_TRY0NULL, map->map_mflags))
map->map_mflags &= ~MF_TRY0NULL;
if (bitset(MF_TRY0NULL, map->map_mflags))
map->map_mflags &= ~MF_TRY0NULL;
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY0NULL;
if (map.map_mflags != (MF_TRY0NULL|MF_TRY1NULL) ||
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY0NULL;