pre_alternate
{ pre_alternate, NULL, 0 }, /* BI */
{ pre_alternate, NULL, 0 }, /* IB */
{ pre_alternate, NULL, 0 }, /* BR */
{ pre_alternate, NULL, 0 }, /* RB */
{ pre_alternate, NULL, 0 }, /* IR */
{ pre_alternate, NULL, 0 }, /* RI */
static int pre_alternate(DECL_ARGS);