Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
.\" .IR head2 .
.SH RETURN VALUE
.BR LIST_EMPTY ()
-returns non-zero if the list is empty,
+returns nonzero if the list is empty,
and zero if the list contains at least one entry.
.PP
.BR LIST_FIRST (),
.\" .IR head2 .
.SH RETURN VALUE
.BR SLIST_EMPTY ()
-returns non-zero if the list is empty,
+returns nonzero if the list is empty,
and zero if the list contains at least one entry.
.PP
.BR SLIST_FIRST (),
POSIX.1 specifies only that:
.RS
.PP
-The sign of a non-zero return value shall be determined by the sign
+The sign of a nonzero return value shall be determined by the sign
of the difference between the values of the first pair of bytes
(both interpreted as type
.IR "unsigned char" )