<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>Db::err()</title> <link rel="stylesheet" href="apiReference.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Berkeley DB C++ API Reference" /> <link rel="up" href="db.html" title="Chapter 2. The Db Handle" /> <link rel="prev" href="dbdel.html" title="Db::del()" /> <link rel="next" href="dbexists.html" title="Db::exists()" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">Db::err()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="dbdel.html">Prev</a> </td> <th width="60%" align="center">Chapter 2. The Db Handle </th> <td width="20%" align="right"> <a accesskey="n" href="dbexists.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="dberr"></a>Db::err()</h2> </div> </div> </div> <pre class="programlisting">#include <db_cxx.h> Db::err(int error, const char *fmt, ...); Db::errx(const char *fmt, ...);</pre> <p> The <a class="xref" href="enverr.html" title="DbEnv::err()">DbEnv::err()</a>, <code class="methodname">DbEnv::errx()</code>, <code class="methodname">Db::err()</code> and <code class="methodname">Db::errx()</code> methods provide error-messaging functionality for applications written using the Berkeley DB library. </p> <p> The <code class="methodname">Db::err()</code> and <a class="xref" href="enverr.html" title="DbEnv::err()">DbEnv::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="DbEnv::set_errcall()">DbEnv::set_errcall()</a> method, any prefix string specified using the <a class="xref" href="envset_errpfx.html" title="DbEnv::set_errpfx()">DbEnv::set_errpfx()</a> method, followed by two separating characters: a colon and a <space> 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 <space> 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="DbEnv::strerror()">DbEnv::strerror()</a> method. </p> </li> </ul> </div> <p> The <code class="methodname">Db::errx()</code> and <code class="methodname">DbEnv::errx()</code> methods are the same as the <code class="methodname">Db::err()</code> and <a class="xref" href="enverr.html" title="DbEnv::err()">DbEnv::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::set_errcall()">Db::set_errcall()</a> and <a class="xref" href="envset_errcall.html" title="DbEnv::set_errcall()">DbEnv::set_errcall()</a>), that function is called with two parameters: any prefix string specified (see <a class="xref" href="dbset_errpfx.html" title="Db::set_errpfx()">Db::set_errpfx()</a> and <a class="xref" href="envset_errpfx.html" title="DbEnv::set_errpfx()">DbEnv::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::set_errfile()">Db::set_errfile()</a> and <a class="xref" href="envset_errfile.html" title="DbEnv::set_errfile()">DbEnv::set_errfile()</a>), the error message is written to that output stream. </p> </li> <li> <p> If a C++ ostream has been set (see <a class="xref" href="envset_error_stream.html" title="DbEnv::set_error_stream()">DbEnv::set_error_stream()</a> and <a class="xref" href="dbset_error_stream.html" title="Db::set_error_stream()">Db::set_error_stream()</a>), the error message is written to that 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="idp4339256"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp4577400"></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="DbEnv::err()">DbEnv::err()</a> and <code class="methodname">Db::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="idp4690776"></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="idp3884048"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp2415496"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="dbdel.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="db.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="dbexists.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Db::del() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> Db::exists()</td> </tr> </table> </div> </body> </html>