# DbEnv::set_tx_recover

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    #include <db_cxx.h>

    int
    DbEnv::set_tx_recover(int (*)(DbEnv *dbenv,
        Dbt *log_rec, DbLsn *lsn, db_recops op));

# Description

Set the application's method to be called during transaction abort and recovery. This method must return 0 on success and either errno or a value outside of the Berkeley DB error name space on failure. It takes four arguments:

dbenv
  A Berkeley DB environment.

log_rec
  A log record.

lsn
  A log sequence number.

op
  One of the following values:

  DB_TXN_BACKWARD_ROLL
    The log is being read backward to determine which transactions have been committed and to abort those operations that were not; undo the operation described by the log record.

  DB_TXN_FORWARD_ROLL
    The log is being played forward; redo the operation described by the log record.

  DB_TXN_ABORT
    The log is being read backward during a transaction abort; undo the operation described by the log record.

The DbEnv::set_tx_recover interface may be used only to configure Berkeley DB before the DbEnv::open interface is called.

The DbEnv::set_tx_recover method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

# Errors

The DbEnv::set_tx_recover method may fail and throw an exception or return a non-zero error for the following conditions:

EINVAL
  An invalid flag value or parameter was specified.

  Called after DbEnv::open was called.

The DbEnv::set_tx_recover method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the DbEnv::set_tx_recover method may fail and either return DB_RUNRECOVERY or throw an exception encapsulating DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

DbEnv, DbTxn

# See Also

DbEnv::set_tx_max, DbEnv::set_tx_recover, DbEnv::set_tx_timestamp, DbTxn::abort, DbEnv::txn_begin, DbEnv::txn_checkpoint, DbTxn::commit, DbTxn::discard, DbTxn::id, DbTxn::prepare, DbEnv::txn_recover, and DbEnv::txn_stat.`

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