Introduction
The function IBApi.EClient.reqWshMetaData is used to request available event types, or supported filter values, that may be used in the call for [EClient.reqWshEventData()](/tws-api/doc/wall-street-horizon/event-data/wsh-event-data-object) filter field.
Regardless of whether or not you are aware of the Meta Data filters, this request must always be called once per session prior to the [EClient.reqWshEventData()](/tws-api/doc/wall-street-horizon/event-data/wsh-event-data-object) function.

