Re: how to code a "lookahead"?

["Richard B Baird" <rbaird@xxxxxxxxxxxxxxxxxxxxx>]

your problem with lookahead fields is that the file must be internally
described.

to get away from that problem, here is an example of how to externally
describe them - sort of.

just make sure your record length is greater than or equal to the actual
files record length.

also, lookahead only works for Input files, not Update.

hth,

Rick

Fextfile   IP   F  200        disk

Dfileext1       e ds                  extname(extfile)  prefix(p)Dfileext2
e ds                  extname(extfile)  prefix(l)

Iextfile   ns  01
I                                  1  200  data

I          aa  **
I                                  1  200  lookahead

C                   if        *in01
C                   eval      fileext1 = data
C                   eval      fileext2 = lookahead
C                   end

 * you now have the data from fields in
 * both the current record (prefixed with 'p')
 * and the fields from the next record
 * (prefixed with 'l') in your programs

 * When a record is being processed from a combined
 * file or an update file, the data in the
 * lookahead field is the same as the data in the
 * record being processed, not the data in the
 * not the data in the next record.