This function is only used to send the request for information; it returns immediately but with no data.
When information is retrieved from the server, addons are notified through the QUEST_QUERY_COMPLETE event. You may then use GetQuestsCompleted() to get the list of completed quests.
Use of this function is throttled by the server. If a query has been performed in the last 60 seconds, calls to this function will be ignored.
Patch changes[]
Patch 5.0.4 (2012-08-28): Removed. GetQuestsCompleted now returns up-to-date data immediately.