    bt_sp             311 libdb/btree.h  	t->bt_sp->pgno = p; 						\
    bt_sp             312 libdb/btree.h  	t->bt_sp->index = i; 						\
    bt_sp             313 libdb/btree.h  	++t->bt_sp;							\
    bt_sp             315 libdb/btree.h  #define	BT_POP(t)	(t->bt_sp == t->bt_stack ? NULL : --t->bt_sp)
    bt_sp             316 libdb/btree.h  #define	BT_CLR(t)	(t->bt_sp = t->bt_stack)
    bt_sp             318 libdb/btree.h  	EPGNO	 *bt_sp;		/* current stack pointer */