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tpreturn( ) and tpforward( ) Functions
If you call a process while running in transaction mode, tpreturn() and tpforward() place the service portion of the transaction in a state that allows it to be either committed or aborted when the transaction completes. You can call a service several times on behalf of the same transaction. The system does not fully commit or abort the transaction until the initiator of the transaction calls tpcommit() or tpabort().
Neither tpreturn() nor tpforward() should be called until all outstanding descriptors for the communication calls made within the service have been retrieved. If you call tpreturn() with outstanding descriptors for which rval is set to TPSUCCESS, the system encounters a protocol error and returns TPESVCERR to the process waiting on tpgetrply(). If the process is in transaction mode, the system marks the caller as "abort-only." Even if the initiator of the transaction calls tpcommit(), the system implicitly aborts the transaction. If you call tpreturn() with outstanding descriptors for which rval is set to TPFAIL, the system returns TPESVCFAIL to the process waiting on tpgetrply(). The effect on the transaction is the same.
When you call tpreturn() while running in transaction mode, this function can affect the result of the transaction by the processing errors that it encounters or that are retrieved from the value placed in rval by the application.
You can use tpforward() to indicate that success has been achieved up to a particular point in the processing of a request. If no application errors have been detected, the system invokes tpforward(); otherwise, the system invokes tpreturn() with TPFAIL. If you call tpforward() improperly, the system considers the call a processing error and returns a failed message to the requester.
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Copyright © 2000 BEA Systems, Inc. All rights reserved.
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