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<h1>Db::truncate</h1>
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<h3><pre>
#include <db_cxx.h>
<p>
int
Db::truncate(DbTxn *txnid, u_int32_t *countp, u_int32_t flags);
</pre></h3>
<h1>Description</h1>
<p>The Db::truncate interface empties the database, discarding all
records it contains.
The number of records discarded from the database is returned in
<b>countp</b>.
<p>If the operation is to be transaction-protected (other than by specifying
the DB_AUTO_COMMIT flag), the <b>txnid</b> parameter is a
transaction handle returned from <a href="../api_cxx/txn_begin.html">DbEnv::txn_begin</a>; otherwise, NULL.
<p>The <b>flags</b> value must be set to 0 or
the following value:
<p><dl compact>
<p><dt><a name="DB_AUTO_COMMIT">DB_AUTO_COMMIT</a><dd>Enclose the Db::truncate call within a transaction. If the call succeeds,
changes made by the operation will be recoverable. If the call fails,
the operation will have made no changes.
</dl>
<p>The Db::truncate 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.
<h1>Errors</h1>
<p>The Db::truncate method may fail and throw an exception or return a non-zero error for the following conditions:
<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.
If a catastrophic error has occurred, the Db::truncate method may fail and
either return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a> or throw a
<a href="../api_cxx/runrec_class.html">DbRunRecoveryException</a>,
in which case all subsequent Berkeley DB calls will fail in the same way.
<h1>Class</h1>
<a href="../api_cxx/db_class.html">Db</a>
<h1>See Also</h1>
<a href="../api_cxx/db_list.html">Databases and Related Methods</a>
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