+/**
+ * lc_get - get element by label, maybe change the active set
+ * @lc: the lru cache to operate on
+ * @enr: the label to look up
+ *
+ * Finds an element in the cache, increases its usage count,
+ * "touches" and returns it.
+ *
+ * In case the requested number is not present, it needs to be added to the
+ * cache. Therefore it is possible that an other element becomes evicted from
+ * the cache. In either case, the user is notified so he is able to e.g. keep
+ * a persistent log of the cache changes, and therefore the objects in use.
+ *
+ * Return values:
+ * NULL
+ * The cache was marked %LC_STARVING,
+ * or the requested label was not in the active set
+ * and a changing transaction is still pending (@lc was marked %LC_DIRTY).
+ * Or no unused or free element could be recycled (@lc will be marked as
+ * %LC_STARVING, blocking further lc_get() operations).
+ *
+ * pointer to the element with the REQUESTED element number.
+ * In this case, it can be used right away
+ *
+ * pointer to an UNUSED element with some different element number,
+ * where that different number may also be %LC_FREE.
+ *
+ * In this case, the cache is marked %LC_DIRTY,
+ * so lc_try_lock() will no longer succeed.
+ * The returned element pointer is moved to the "to_be_changed" list,
+ * and registered with the new element number on the hash collision chains,
+ * so it is possible to pick it up from lc_is_used().
+ * Up to "max_pending_changes" (see lc_create()) can be accumulated.
+ * The user now should do whatever housekeeping is necessary,
+ * typically serialize on lc_try_lock_for_transaction(), then call
+ * lc_committed(lc) and lc_unlock(), to finish the change.
+ *
+ * NOTE: The user needs to check the lc_number on EACH use, so he recognizes
+ * any cache set change.