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<h2 class="title" style="clear: both"><a id="envcdsgroup_begin"></a>DB_ENV->cdsgroup_begin()</h2>
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<pre class="programlisting">#include <db.h>
int
DB_ENV->cdsgroup_begin(DB_ENV *dbenv, DB_TXN **tid); </pre>
<p>
The <code class="methodname">DB_ENV->cdsgroup_begin()</code> method allocates a locker ID in an
environment configured for Berkeley DB Concurrent Data Store
applications. It copies a pointer to a
<a class="link" href="txn.html" title="Chapter 12. The DB_TXN Handle">DB_TXN</a> that uniquely identifies
the locker ID into the memory to which <span class="bold"><strong>tid</strong></span> refers.
Calling the
<a class="xref" href="txncommit.html" title="DB_TXN->commit()">DB_TXN->commit()</a> method will
discard the allocated locker ID.
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<p>
See <a href="../../programmer_reference/cam.html#cam_intro" class="olink">Berkeley DB Concurrent Data Store applications</a> for more information about when this is
required.
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<p>
The <code class="methodname">DB_ENV->cdsgroup_begin()</code> method may be called at any time during
the life of the application.
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<p>
The <code class="methodname">DB_ENV->cdsgroup_begin()</code> <span>
<span>
method returns a non-zero error value on failure and 0 on success.
</span>
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<h3 class="title"><a id="id1707449"></a>Errors</h3>
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<p>
The <code class="methodname">DB_ENV->cdsgroup_begin()</code> <span>
<span>
method may fail and return one of the following non-zero errors:
</span>
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<h4 class="title"><a id="id1707248"></a>ENOMEM</h4>
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The maximum number of lockers has been reached.
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<h3 class="title"><a id="id1707450"></a>Class</h3>
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<p>
<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>, <a class="link" href="txn.html" title="Chapter 12. The DB_TXN Handle">DB_TXN</a>
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<h3 class="title"><a id="id1707510"></a>See Also</h3>
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<a class="xref" href="txn.html#txnlist" title="Transaction Subsystem and Related Methods">Transaction Subsystem and Related Methods</a>
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