bt_stack          342 libdb/btree.h  #define	BT_POP(t)	(t->bt_sp == t->bt_stack ? NULL : --t->bt_sp)
bt_stack          343 libdb/btree.h  #define	BT_CLR(t)	(t->bt_sp = t->bt_stack)
bt_stack          344 libdb/btree.h  	EPGNO	  bt_stack[50];		/**< stack of parent pages */