As part of the general rules for APPC basic conversations, the user data
must be in LL-ID-data format (where LL and ID are each two bytes long), and
must follow the attach FMH-5 header. The CICS DFHCLS4 program requires the
user input data stream to fit into the format shown in
Figure 1;
if it does not, CICS rejects the data.
Figure 1. Format of user data.
Note: - This is an attach FMH-5 header with its data. Data is passed between the PEM client
and the CICS PEM server via GDS variables. (For information on GDS,
see the SNA LU 6.2 Peer Protocols manual.)
- The GDS record contains GDS data in the format LL-ID-data where:
- LL, which is two bytes long, is the length of the GDS
record, including the LL and ID lengths.
- ID, which is two bytes long, indicates what the data
record represents; for example, X'1221' (sign-on data).
- The GDS data record is itself an LL-ID-data record; in this example, a
transaction program record (or TP record) where:
- LL, which is two bytes long, is the length of the TP
record including the LL and ID lengths.
- ID which is two bytes long, indicates the function the
TP is to perform; for example, X'FF00' (sign-on) or X'FF01' (signon
and change password).
- The TP data record is divided up into L-ID-data records (where L and ID
are each one byte long). These are known as subfield (or SF records)
where:
- L is the length of the SF record, including the L and ID lengths.
- ID indicates the subfield being passed; for example, X'01' (userid), X'02' (password),
and X'06' (new password).
