Registers a callback method to be invoked whenever a transaction is rolled back.

Arguments: The arguments are:
callBackObj [required] An instantiated object with a method that will be invoked whenever a transaction is rolled back. However, this argument can also be .nil to indicate that any installed rollback hook is to be removed.
mthName [optional] The method name that will be invoked during a call back. By default, the method invoked will berollbackHookCallBack(). However, the user can specify an alternative method if desired. This argument is ignored when thecallbackObjargument is .nil.
userData [optional] This can be any Rexx object the user desires. The object will be sent as the first and only argument to the rollback hook callback method when it is invoked. This argument is ignored when the callbackObj argument is .nil.
Return value: TheuserDataargument to a previous invocation of therollbackHookmethod on this database connection, or .nil if there has not been a previous invocation or theuserDataargument was not used on the previous invocation.
Details: The functionality of therollbackHookmethod is similar to that of the SQLite sqlite3_rollback_hook API.