mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 01:26:25 +00:00
210 lines
7.9 KiB
HTML
210 lines
7.9 KiB
HTML
<?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>Dbc::count()</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="dbc.html" title="Chapter 3. The Dbc Handle" />
|
||
<link rel="prev" href="dbccmp.html" title="Dbc::cmp()" />
|
||
<link rel="next" href="dbcdel.html" title="Dbc::del()" />
|
||
</head>
|
||
<body>
|
||
<div xmlns="" class="navheader">
|
||
<div class="libver">
|
||
<p>Library Version 11.2.5.2</p>
|
||
</div>
|
||
<table width="100%" summary="Navigation header">
|
||
<tr>
|
||
<th colspan="3" align="center">Dbc::count()</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="dbccmp.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 3.
|
||
The Dbc Handle
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="dbcdel.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="dbccount"></a>Dbc::count()</h2>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<pre class="programlisting">#include <db_cxx.h>
|
||
|
||
int
|
||
Dbc::count(db_recno_t *countp, u_int32_t flags);</pre>
|
||
<p>
|
||
The <code class="methodname">Dbc::count()</code> method returns a count of the number of data
|
||
items for the key to which the cursor refers.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">Dbc::count()</code> <span>
|
||
|
||
<span>
|
||
method either returns a non-zero error value or throws an
|
||
exception that encapsulates a non-zero error value on
|
||
failure, and returns 0 on success.
|
||
</span>
|
||
</span>
|
||
</p>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3585064"></a>Parameters</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3585099"></a>countp</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>countp</strong></span> parameter references
|
||
memory into which the count of the number of duplicate data items is
|
||
copied.
|
||
</p>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3584662"></a>flags</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>flags</strong></span> parameter is currently
|
||
unused, and must be set to 0.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3585015"></a>Errors</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <code class="methodname">Dbc::count()</code> <span>
|
||
|
||
<span>
|
||
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
|
||
exception, encapsulating one of the following non-zero errors, or return one
|
||
of the following non-zero errors:
|
||
</span>
|
||
</span>
|
||
</p>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3584775"></a> <span>DbRepHandleDeadException or</span> DB_REP_HANDLE_DEAD</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
When a client synchronizes with the master, it is possible for committed
|
||
transactions to be rolled back. This invalidates all the database and cursor
|
||
handles opened in the replication environment. Once this occurs, an attempt to use
|
||
such a handle will
|
||
<span>
|
||
throw a <a class="xref" href="dbrephandledead.html" title="DbRepHandleDeadException">DbRepHandleDeadException</a> (if
|
||
your application is configured to throw exceptions), or
|
||
</span>
|
||
return <code class="literal">DB_REP_HANDLE_DEAD</code>.
|
||
The application will need to discard the handle and open a new one in order to
|
||
continue processing.
|
||
</p>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3585006"></a><span>DbDeadlockException or </span>DB_REP_LOCKOUT</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The operation was blocked by client/master synchronization.
|
||
</p>
|
||
<p>
|
||
<a class="xref" href="dbdeadlock.html" title="DbDeadlockException">DbDeadlockException</a> is thrown if
|
||
your Berkeley DB API is configured to throw exceptions.
|
||
Otherwise, <code class="literal">DB_REP_LOCKOUT</code> is returned.
|
||
</p>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3585203"></a>EINVAL</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
If the cursor has not been initialized; or if an invalid flag value or parameter was specified.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3584804"></a>Class</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="link" href="dbc.html" title="Chapter 3. The Dbc Handle">Dbc</a>
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3585212"></a>See Also</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="xref" href="dbc.html#dbclist" title="Database Cursors and Related Methods">Database Cursors 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="dbccmp.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="dbc.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="dbcdel.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">Dbc::cmp() </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top"> Dbc::del()</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|