BIT_ONLYONESET
brand_assert(BIT_ONLYONESET(est->st_args & RV_MASK));
ASSERT(BIT_ONLYONESET(blksize));
ASSERT(by && BIT_ONLYONESET(by));
ASSERT(BIT_ONLYONESET(blksize));
ASSERT(BIT_ONLYONESET(blksize));
ASSERT(BIT_ONLYONESET(blksize));
ASSERT(BIT_ONLYONESET(blksize));