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<! "@(#)cursor.so 10.10 (Sleepycat) 11/21/98">
<!Copyright 1997, 1998 by Sleepycat Software, Inc. All rights reserved.>
<html>
<body bgcolor=white>
<head>
<title>Berkeley DB: DB->cursor</title>
<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
<meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btr
ee,hash,hashing,transaction,transactions,locking,logging,access method,access me
thods,java,C,C++">
</head>
<h1>DB->cursor</h1>
<hr size=1 noshade>
<tt>
<h3>
<pre>
#include <db.h>
<p>
int
DB->cursor(DB *db,
DB_TXN *txnid, DBC **cursorp, u_int32_t flags);
</pre>
</h3>
<h1>Description</h1>
<p>
The DB->cursor function
creates a cursor and copies a pointer to it into the memory referenced
by <b>cursorp</b>.
<p>
A cursor is a structure used to provide sequential access through a database.
This interface and its associated functions replaces the functionality
provided by the <b>seq</b> function in previous releases of Berkeley DB.
<p>
If the file is being accessed under transaction protection,
the <b>txnid</b> parameter is a transaction ID returned from
<a href="../../api_c/DbTxnMgr/begin.html">txn_begin</a>, otherwise, NULL.
If transaction protection is enabled, cursors must be opened and closed
within the context of a transaction, and the <b>txnid</b> parameter
specifies the transaction context in which the cursor may be used.
<p>
The <b>flags</b> parameter must be set to 0.
<p>
In addition, the following value may be set by logically <b>OR</b>'ing it into the
<b>flags</b> parameter:
<dl compact>
<p><dt>DB_RMW<dd>Specify that the cursor will be used to update the database. This
flag should <b>only</b> be set when the <a href="../../api_c/DbEnv/appinit.html#DB_INIT_CDB">DB_INIT_CDB</a> flag
was specified to <a href="../../api_c/DbEnv/appinit.html">db_appinit</a>.
</dl>
<p>
The DB->cursor
function returns the value of <b>errno</b> on failure, and 0 on success.
<p>
<h1>Errors</h1>
If a fatal error occurs in Berkeley DB, the DB->cursor function may fail and return
DB_RUNRECOVERY, at which point all subsequent database calls will also
return DB_RUNRECOVERY.
<p>
The DB->cursor
function may fail and return <b>errno</b>
for any of the errors specified for the following Berkeley DB and C library
functions:
__ham_c_init(3),
free(3),
<a href="../../api_c/DbLockTab/id.html">lock_id</a>,
malloc(3),
memcpy(3),
and
memset(3).
<p>
In addition, the DB->cursor
function may fail and return <b>errno</b>
for the following conditions:
<p>
<dl compact>
<p><dt>EINVAL<dd>An invalid flag value or parameter was specified.
<p>
</dl>
<p>
<h1>See Also</h1>
<a href="../../api_c/DbEnv/appexit.html">db_appexit</a>,
<a href="../../api_c/DbEnv/appinit.html">db_appinit</a>,
<a href="../../api_c/DbEnv/version.html">db_version</a>,
<a href="../../api_c/Db/close.html">DB->close</a>,
DB->cursor,
<a href="../../api_c/Db/del.html">DB->del</a>,
<a href="../../api_c/Db/fd.html">DB->fd</a>,
<a href="../../api_c/Db/get.html">DB->get</a>,
<a href="../../api_c/Db/join.html">DB->join</a>,
<a href="../../api_c/Db/open.html">db_open</a>,
<a href="../../api_c/Db/put.html">DB->put</a>,
<a href="../../api_c/Db/stat.html">DB->stat</a>,
<a href="../../api_c/Db/sync.html">DB->sync</a>,
<a href="../../api_c/Dbc/close.html">DBcursor->c_close</a>,
<a href="../../api_c/Dbc/del.html">DBcursor->c_del</a>,
<a href="../../api_c/Dbc/get.html">DBcursor->c_get</a>
and
<a href="../../api_c/Dbc/put.html">DBcursor->c_put</a>.
</tt>
</body>
</html>
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