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<div class="sect1" lang="en" xml:lang="en">
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<div>
<h2 class="title" style="clear: both"><a id="envset_feedback"></a>DbEnv::set_feedback()</h2>
</div>
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</div>
<pre class="programlisting">#include <db_cxx.h>
int
DbEnv::set_feedback(void (*db_feedback_fcn)(DbEnv *dbenv, int opcode,
int percent));</pre>
<p>
Some operations performed by the Berkeley DB library can take
non-trivial amounts of time. The <code class="methodname">DbEnv::set_feedback()</code> method can
be used by applications to monitor progress within these operations.
When an operation is likely to take a long time, Berkeley DB will call
the specified callback function with progress information.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
Berkeley DB is not re-entrant. Callback functions should not attempt to make library calls (for
example, to release locks or close open handles). Re-entering Berkeley DB is not guaranteed to work
correctly, and the results are undefined.
</p>
</div>
<p>
It is up to the callback function to display this information in an
appropriate manner.
</p>
<p>
The <code class="methodname">DbEnv::set_feedback()</code> method configures operations performed
using the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle.
</p>
<p>
The <code class="methodname">DbEnv::set_feedback()</code> method may be called at any time during
the life of the application.
</p>
<p>
The <code class="methodname">DbEnv::set_feedback()</code> method returns a non-zero error value on
failure and 0 on success.
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp7373832"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp7374024"></a>db_feedback_fcn</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>db_feedback_fcn</strong></span> parameter is the
application-specified feedback function called to report Berkeley DB
operation progress. The callback function must take three parameters:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<code class="literal">dbenv</code>
</p>
<p>
The <span class="bold"><strong>dbenv</strong></span> parameter is a reference to
the enclosing database environment.
</p>
</li>
<li>
<p>
<code class="literal">opcode</code>
</p>
<p>
The <span class="bold"><strong>opcode</strong></span> parameter is an operation
code. The <span class="bold"><strong>opcode</strong></span> parameter may take
on any of the following values:
</p>
<div class="itemizedlist">
<ul type="circle">
<li>
<p><a id="set_feedback_DB_RECOVER"></a>
<code class="literal">DB_RECOVER</code>
</p>
<p>
The environment is being recovered.
</p>
</li>
</ul>
</div>
</li>
<li>
<p>
<code class="literal">percent</code>
</p>
<p>
The <span class="bold"><strong>percent</strong></span> parameter is the percent
of the operation that has been completed, specified as an integer
value between 0 and 100.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h3 class="title"><a id="idp7396480"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h3 class="title"><a id="idp7375896"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="env.html#envlist" title="Database Environments and Related Methods">Database Environments and Related Methods</a>
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