Uncommon Knowledge - WC_MV%

The variable used by the window processor to indicate which line of an associated multivalued prompt it is currently on. If the prompt is not part of a group (or is not grouped to itself) then this value will not be set. It is therefore not a reliable test for whether the prompt is multivalued. If this is required, check the contents of WC_DELIM% q.v.

(Volume 3, Issue 6, Page 13)