`(multiple-value-bind (,word ,bit) (floor ,offset 32)
(setf (deref (slot ,fd-set 'fds-bits) ,word)
(logand (deref (slot ,fd-set 'fds-bits) ,word)
`(multiple-value-bind (,word ,bit) (floor ,offset 32)
(setf (deref (slot ,fd-set 'fds-bits) ,word)
(logand (deref (slot ,fd-set 'fds-bits) ,word)