[sqlite] sqlite3_update_hook() clarification

[Sairam Gaddam]

http://www.sqlite.org/c3ref/update_hook.html

The documentation says that the function sqlite3_update_hook() is called
whenever a row is updated, deleted or inserted for a rowid table. But I
don't find this function to be invoked in my program. When will this
function be invoked??
And I am interested in its second parameter which gives the details of
table and the rowid of row which is updated. It is a callback function.

SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
  void *pArg                /* Argument to the function */
)

And I don't find any definition for this callback routine.

Can anyone kindly give information on this?