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<title>Berkeley DB: Db::truncate</title>
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#include <db_cxx.h>
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Db::truncate(DbTxn *txnid, u_int32_t *countp, u_int32_t flags);
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<p>The Db::truncate interface empties the database, discarding all
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The number of records discarded from the database is returned in
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<p>If the operation is to be transaction-protected (other than by specifying
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the DB_AUTO_COMMIT flag), the <b>txnid</b> parameter is a
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transaction handle returned from <a href="../api_cxx/txn_begin.html">DbEnv::txn_begin</a>; otherwise, NULL.
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<p>The <b>flags</b> value must be set to 0 or
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<p><dt><a name="DB_AUTO_COMMIT">DB_AUTO_COMMIT</a><dd>Enclose the Db::truncate call within a transaction. If the call succeeds,
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changes made by the operation will be recoverable. If the call fails,
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the operation will have made no changes.
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<p>The Db::truncate method either returns a non-zero error value or throws an exception that
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encapsulates a non-zero error value on failure, and returns 0 on success.
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<p>The Db::truncate method may fail and throw an exception or return a non-zero error for the following conditions:
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<p>The Db::truncate 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.
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If a catastrophic error has occurred, the Db::truncate method may fail and
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either return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a> or throw a
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<a href="../api_cxx/runrec_class.html">DbRunRecoveryException</a>,
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in which case all subsequent Berkeley DB calls will fail in the same way.
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