I've become accustomed to D3 and always using list-names, as opposed
to list-numbers. I was a little confused by the UniData manual
"UniBasic Commands Reference" from 26/11/04 and it cost me quite a
bit of time and frustration. It says, under the SELECT statement:
"Note: You can specify named or numbered lists (using list.num.expr
or list.var.expr) in BASICTYPEs R and U. Only named lists
(list.var.expr) are supported in BASICTYPEs M and P."

Then, under the READNEXT statement:
"READNEXT id.var [, val.var[, subval.var]] [FROM list.num.expr] [ON
ERROR statements] {THEN statements [END] | ELSE statements [END]}"

and
"Note: READNEXT performs differently with BASICTYPEs M and P as
shown in the following syntax: READNEXT var FROM list.name {,
acct.name} [SETTING count.var] {THEN statements [END] | ELSE statements
[END]}."

We use BASICTYPE U. According to the manual I can SELECT TO
list.var.expr but, because we aren't using BASICTYPE M or P, I
can't READNEXT from list.var.expr. "What then should I use to pass
thru list.var.exp" I wondered. I did a search of the PDF document for
list.var.exp and found that the only reference to it was the one under
SELECT. I concluded this must be a mistake (illogical) and so wrote a
little program to try using it in a READNEXT. It worked. So - the
manual is misleading and should be changed.

If there'd been a post like this one here in comp.databases.pick
previously I could have avoided this headache. Btw - I have given up
on the U2 users mailing list because there was far too much in my inbox
each day and the searchable archives won't retrieve information I
know for sure is in there somewhere.

Cheers
Mike.