Setting socket types for IMS TM clients
For IMS Connect clients that access IMS TM, client code controls the socket settings, and the IMS Connect user message exits and the user initialization exit enforce the socket settings.
The client selects the socket connection type by setting
a flag in the IMS request message
(IRM) header, in the field IRM_SOCT. The IRM_SOCT flag values are
shown in the following table.
| Flag | Definition | Socket type |
|---|---|---|
| IRM_SOCT_PER | X'10' | Persistent |
| IRM_TRAN | X'00' | Transaction |
| IRM_SOCT_NONPER | X'40' | Non-persistent |
The IRM_SOCT flag must be set for each message that is sent to IMS Connect from an IMS Connect client that accesses IMS TM.
Recommendation: Set
all messages that are associated with a single transaction to the
same socket type. If you do not, unexpected results can occur, as
described in the following examples:
- If the first message of a conversational transaction is set to persistent, and the last message is set to transaction, then the socket connection will be terminated following the last message.
- If one of the messages in the middle of the conversational transaction set the socket type to transaction, and the IMS transaction terminates for some reason, then IMS Connect will disconnect the socket. This is because "transaction" was the last known socket type.
The user message exits determine the socket type, then
move the socket type information to the user data section of the OTMA
message header that they return to IMS Connect.
To transfer the socket type information to the OTMA message header,
the user exits set the OMUSR_FLAG1 field, which is mapped by the HWSOMUSR
DSECT of the HWSOMPFX macro, with one of the following flags as shown
in the following table:
| Flag | Definition | Socket type |
|---|---|---|
| OMUSR_PSOCKET | X'10' | Persistent |
| OMUSR_TRAN | X'00' | Transaction |
| OMUSR_NPSOCKET | X'40' | Non-persistent |