SLIST_END
#define SLIST_EMPTY(head) ((head)->slh_first == SLIST_END(head))
(var) != SLIST_END(head); \
for ((var) = ((var) != SLIST_END(head) ? (var) : SLIST_FIRST((head))); \
(var) != SLIST_END(head); \
(var) != SLIST_END(head) && \
for ((var) = ((var) != SLIST_END(head) ? (var) : SLIST_FIRST((head))); \
(var) != SLIST_END(head) && \
(head)->slh_first = SLIST_END(head); \
if (curelm == SLIST_END(head1)) { \
SLIST_END(head1)) \
} else if (SLIST_FIRST(head2) != SLIST_END(head2)) { \
while (SLIST_NEXT(curelm, field) != SLIST_END(head1)) \