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<h2 class="title" style="clear: both"><a id="envset_error_stream"></a>DbEnv::set_error_stream()</h2>
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<pre class="programlisting">#include <db_cxx.h>
void DbEnv::set_error_stream(class ostream*); </pre>
<p>
When an error occurs in the Berkeley DB library, an exception
is thrown or an <span class="bold"><strong>errno</strong></span> value
is returned by the interface. In some cases, however, the
<span class="bold"><strong>errno</strong></span> value may be
insufficient to completely describe the cause of the error,
especially during initial application debugging.
</p>
<p>
The <code class="methodname">DbEnv::set_error_stream()</code> and
<a class="xref" href="dbset_error_stream.html" title="Db::set_error_stream()">Db::set_error_stream()</a>
methods are used to enhance the mechanism for reporting error messages to the
application by setting the C++ ostream used for displaying
additional Berkeley DB error messages. In some cases, when an
error occurs, Berkeley DB will output an additional error message
to the specified stream.
</p>
<p>
The error message will consist of the prefix string and a colon
("<span class="bold"><strong>:</strong></span>") (if a prefix string was
previously specified using
<a class="xref" href="dbset_errpfx.html" title="Db::set_errpfx()">Db::set_errpfx()</a>,
an error string, and a trailing <newline> character.
</p>
<p>
Setting <span class="bold"><strong>stream</strong></span> to NULL unconfigures the interface.
</p>
<p>
Alternatively, you can use the
<a class="xref" href="envset_errfile.html" title="DbEnv::set_errfile()">DbEnv::set_errfile()</a> or
<a class="xref" href="dbset_errfile.html" title="Db::set_errfile()">Db::set_errfile()</a> methods
to display the additional information via a C Library <code class="literal">FILE *</code>,
or the <a class="xref" href="envset_errcall.html" title="DbEnv::set_errcall()">DbEnv::set_errcall()</a>
and <a class="xref" href="dbset_errcall.html" title="Db::set_errcall()">Db::set_errcall()</a>
methods to capture the additional error information in a way that does not use either
output streams or C Library <code class="literal">FILE *</code>'s.
You should not mix these approaches.
</p>
<p>
This error-logging enhancement does not slow performance or significantly increase
application size, and may be run during normal operation as well as during application
debugging.
</p>
<p>
The <code class="methodname">DbEnv::set_error_stream()</code> method configures operations
performed using the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle,
not all operations performed on the underlying database environment.
</p>
<p>
The <code class="methodname">DbEnv::set_error_stream()</code> method may be called at any time during the
life of the application.
</p>
<div class="sect2" lang="en" xml:lang="en">
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<h3 class="title"><a id="id1671523"></a>Parameters</h3>
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<h4 class="title"><a id="id1671500"></a>stream</h4>
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<p>
The <span class="bold"><strong>stream</strong></span> parameter is the
application-specified output stream to be used for additional error
information.
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<div class="sect2" lang="en" xml:lang="en">
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<h3 class="title"><a id="id1671665"></a>Class</h3>
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<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>
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<h3 class="title"><a id="id1671440"></a>See Also</h3>
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<a class="xref" href="env.html#envlist" title="Database Environments and Related Methods">Database Environments and Related Methods</a>
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