11.29.3 Called Service That Starts a New Explicit Transaction

If a communication call is made with TPNOTRAN, and the called service is not automatically placed in transaction mode by a configuration option, the service can define multiple transactions using explicit calls to tpbegin(), tpcommit(), and tpabort(). As a result, the transaction can be completed before a call is issued to tpreturn().

In this situation, the following facts apply:

• tpreturn() plays no transaction role; that is, the role of tpreturn() is always the same, regardless of whether transactions are explicitly defined in the service routine.
• tpreturn() can return any value in rval, regardless of the outcome of the transaction.
• Typically, the system returns processing errors, buffer type errors, or application failure, and follows the normal rules for TPESVCFAIL, TPEITYPE/TPEOTYPE, and TPESVCERR.
• The state of the caller’s transaction is not affected by any failed messages or application failures returned to the caller.
• The caller is vulnerable to the possibility that its own transaction may time out as it waits for its reply.
• If no reply is expected, the caller’s transaction cannot be affected in any way by the communication call.