If you use byte-oriented operations (for example, STRING, UNSTRING, or reference modification) on an alphanumeric data item that contains DBCS characters, results are unpredictable. You should instead convert the item to a national data item before you process it.
That is, do these steps:
related tasks
Joining data items (STRING)
Splitting data items (UNSTRING)
Referring to substrings of data items
Converting to or from national (Unicode) representation