void *ltt_event_data(LttEvent *e);
-/* The number of elements in a sequence field is specific to each event.
- This function returns the number of elements for an array or sequence
- field in an event. */
+/* The number of elements in a sequence field is specific to each event
+ instance. This function returns the number of elements for an array or
+ sequence field in an event. */
unsigned ltt_event_field_element_number(LttEvent *e, LttField *f);
void ltt_event_field_element_select(LttEvent *e, LttField *f, unsigned i);
+/* A union is like a structure except that only a single member at a time
+ is present depending on the specific event instance. This function tells
+ the active member for a union field in an event. */
+
+unsigned ltt_event_field_union_member(LttEvent *e, LttField *f);
+
+
/* These functions extract data from an event after architecture specific
conversions. */