SH_TAILQ_NEXTP
((elm)->field.stqe_next == -1 ? NULL : SH_TAILQ_NEXTP(elm, field, type))
SH_TAILQ_NEXTP(listelm, field, type)->field.stqe_prev = \
SH_TAILQ_NEXTP(elm, field, type)->field.stqe_prev = \
SH_PTR_TO_OFF(SH_TAILQ_NEXTP(elm, \