/* Macros for internal use only. */
#define ll_data__(LL, STRUCT, MEMBER, LIST) \
((LL) != ll_null (LIST) ? ll_data (LL, STRUCT, MEMBER) : NULL)
#define ll_head__(STRUCT, MEMBER, LIST) \
ll_data__ (ll_head (LIST), STRUCT, MEMBER, LIST)
/* Macros for internal use only. */
#define ll_data__(LL, STRUCT, MEMBER, LIST) \
((LL) != ll_null (LIST) ? ll_data (LL, STRUCT, MEMBER) : NULL)
#define ll_head__(STRUCT, MEMBER, LIST) \
ll_data__ (ll_head (LIST), STRUCT, MEMBER, LIST)