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<th colspan="3" align="center">DB-&gt;err()</th>
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<td width="20%" align="left"><a accesskey="p" href="dbdel.html">Prev</a> </td>
<th width="60%" align="center">Chapter 2. 
The DB Handle
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<div class="sect1" lang="en" xml:lang="en">
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<h2 class="title" style="clear: both"><a id="dberr"></a>DB-&gt;err()</h2>
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<pre class="programlisting">#include &lt;db.h&gt;
void
DB-&gt;err(DB *db, int error, const char *fmt, ...);
void
DB-&gt;errx(DB *db, const char *fmt, ...); </pre>
<p>
The <a class="xref" href="enverr.html" title="DB_ENV-&gt;err()">DB_ENV-&gt;err()</a>,
<code class="methodname">DB_ENV-&gt;errx()</code>, <code class="methodname">DB-&gt;err()</code> and
<code class="methodname">DB-&gt;errx()</code> methods provide error-messaging functionality for
applications written using the Berkeley DB library.
</p>
<p>
The <code class="methodname">DB-&gt;err()</code> and <a class="xref" href="enverr.html" title="DB_ENV-&gt;err()">DB_ENV-&gt;err()</a> methods construct
an error message consisting of the following elements:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>An optional prefix string</strong></span>
</p>
<p>
If no error callback function has been set using the
<a class="xref" href="envset_errcall.html" title="DB_ENV-&gt;set_errcall()">DB_ENV-&gt;set_errcall()</a>
method, any prefix string specified using the
<a class="xref" href="envset_errpfx.html" title="DB_ENV-&gt;set_errpfx()">DB_ENV-&gt;set_errpfx()</a>
method, followed by two separating characters: a colon and a
&lt;space&gt; character.
</p>
</li>
<li>
<p>
<span class="bold"><strong>An optional printf-style message</strong></span>
</p>
<p>
The supplied message <span class="bold"><strong>fmt</strong></span>, if
non-NULL, in which the ANSI C X3.159-1989 (ANSI C) printf function
specifies how subsequent parameters are converted for output.
</p>
</li>
<li>
<p>
<span class="bold"><strong>A separator</strong></span>
</p>
<p>
Two separating characters: a colon and a &lt;space&gt; character.
</p>
</li>
<li>
<p>
<span class="bold"><strong>A standard error string</strong></span>
</p>
<p>
The standard system or Berkeley DB library error string associated
with the <span class="bold"><strong>error</strong></span> value, as returned by
the <a class="xref" href="envstrerror.html" title="db_strerror">db_strerror</a>
method.
</p>
</li>
</ul>
</div>
<p>
The <code class="methodname">DB-&gt;errx()</code> and <code class="methodname">DB_ENV-&gt;errx()</code> methods
are the same as the <code class="methodname">DB-&gt;err()</code> and
<a class="xref" href="enverr.html" title="DB_ENV-&gt;err()">DB_ENV-&gt;err()</a> methods, except they do not append
the final separator characters and standard error string to the error message.
</p>
<p>
This constructed error message is then handled as follows:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
If an error callback function has been set (see
<a class="xref" href="dbset_errcall.html" title="DB-&gt;set_errcall()">DB-&gt;set_errcall()</a> and
<a class="xref" href="envset_errcall.html" title="DB_ENV-&gt;set_errcall()">DB_ENV-&gt;set_errcall()</a>),
that function is called with two parameters: any prefix string
specified (see <a class="xref" href="dbset_errpfx.html" title="DB-&gt;set_errpfx()">DB-&gt;set_errpfx()</a>
and <a class="xref" href="envset_errpfx.html" title="DB_ENV-&gt;set_errpfx()">DB_ENV-&gt;set_errpfx()</a>) and
the error message.
</p>
</li>
<li>
<p>
If a C library FILE * has been set (see
<a class="xref" href="dbset_errfile.html" title="DB-&gt;set_errfile()">DB-&gt;set_errfile()</a> and
<a class="xref" href="envset_errfile.html" title="DB_ENV-&gt;set_errfile()">DB_ENV-&gt;set_errfile()</a>),
the error message is written to that output stream.
</p>
</li>
<li>
<p>
If none of these output options have been configured, the error message
is written to stderr, the standard error output stream.
</p>
</li>
</ul>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp57451312"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp57420464"></a>error</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>error</strong></span> parameter is the error
value for which the <a class="xref" href="enverr.html" title="DB_ENV-&gt;err()">DB_ENV-&gt;err()</a>
and <code class="methodname">DB-&gt;err()</code> methods will display an explanatory string.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp57490736"></a>fmt</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>fmt</strong></span> parameter is an optional
printf-style message to display.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp57425536"></a>Class</h3>
</div>
</div>
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<p>
<a class="link" href="db.html" title="Chapter 2.  The DB Handle">DB</a>
</p>
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<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h3 class="title"><a id="idp57487424"></a>See Also</h3>
</div>
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<p>
<a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a>
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