If you poke the message reference into a search-engine, you should get to the description in the KnowledgeCentre, which will lead to this:
the length for a field with a format other than SS was greater than 256
I suggest you use the match-marker in the REFORMAT statement, a ? (question-mark) which you then test for 1 (on 1, not on 2), 2 (on 2 not on 1) and B (a match), which will simplify things (you don't need the FILL) and to do your test you'll have to split the field into multiple ones.
thnx very much.
When the match marker has the value B does that mean that the key, as specified in JOINKEYS, appears in both files?
But concerning the B value I want to know two situations:
1. key in both files and no values of attributes changed
2. key in both files but there is a change of values of atributes
You test for the B, and then, as Arun has shown, split your test for more than 256 characters into multiple tests for 256-byte fields, twice, and a final one for the balance of the bytes, connected with AND.