struct xLIST_ITEM { listFIRST_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */ configLIST_VOLATILE TickType_t xItemValue; /*< The value being listed. In most cases this is used to sort the list in descending order. */ struct xLIST_ITEM * configLIST_VOLATILE pxNext; /*< Pointer to the next ListItem_t in the list. */ struct xLIST_ITEM * configLIST_VOLATILE pxPrevious; /*< Pointer to the previous ListItem_t in the list. */ void * pvOwner; /*< Pointer to the object (normally a TCB) that contains the list item. There is therefore a two way link between the object containing the list item and the list item itself. */ struct xLIST * configLIST_VOLATILE pxContainer; /*< Pointer to the list in which this list item is placed (if any). */ listSECOND_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */ };

这是一个双向链表（doubly linked list）的结构体定义。其中，TickType_t xItemValue是链表节点的值，pxNext和pxPrevious分别指向下一个和上一个节点，pvOwner指向包含该节点的对象，pxContainer指向包含该节点的链表。这个结构体也包含了一些用于数据完整性检查的变量，这些变量只有在configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES被设置为1时才会使用。