int DB_TXN->discard(DB_TXN *tid, u_int32_t flags);
The DB_TXN->discard method frees up all the per-process resources associated with the specified DB_TXN handle, neither committing nor aborting the transaction. This call may be used only after calls to DB_ENV->txn_recover when there are multiple global transaction managers recovering transactions in a single Berkeley DB environment. Any transactions returned by DB_ENV->txn_recover that are not handled by the current global transaction manager should be discarded using DB_TXN->discard.
The flags parameter is currently unused, and must be set to 0.
The DB_TXN->discard method returns EINVAL if the transaction handle does not refer to a transaction that was recovered into a prepared but not yet completed state. Otherwise, the DB_TXN->discard method returns a non-zero error value on failure and 0 on success.
After DB_TXN->discard has been called, regardless of its return, the DB_TXN handle may not be accessed again.
The DB_TXN->discard method may fail and return a non-zero error for the following conditions:
The transaction handle does not refer to a transaction that was recovered into a prepared but not yet completed state.
The DB_TXN->discard method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DB_TXN->discard method may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.
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