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<! "@(#)prepare.so 10.8 (Sleepycat) 9/29/98">
<!Copyright 1997, 1998 by Sleepycat Software, Inc. All rights reserved.>
<html>
<body bgcolor=white>
<head>
<title>Berkeley DB: txn_prepare</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>txn_prepare</h1>
<hr size=1 noshade>
<tt>
<h3>
<pre>
#include <db.h>
<p>
int
txn_prepare(DB_TXN *tid);
</pre>
</h3>
<h1>Description</h1>
<p>
The txn_prepare function initiates the beginning of a two-phase commit.
<p>
In a distributed transaction environment, Berkeley DB can be used as a local
transaction manager. In this case, the distributed transaction manager
must send <i>prepare</i> messages to each local manager. The local
manager must then issue a txn_prepare and await its successful
return before responding to the distributed transaction manager. Only
after the distributed transaction manager receives successful responses
from all of its <i>prepare</i> messages should it issue any
<i>commit</i> messages.
<p>
The txn_prepare
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 txn_prepare function may fail and return
DB_RUNRECOVERY, at which point all subsequent database calls will also
return DB_RUNRECOVERY.
<p>
The txn_prepare
function may fail and return <b>errno</b>
for any of the errors specified for the following Berkeley DB and C library
functions:
abort(3),
fcntl(3),
fflush(3),
fprintf(3),
free(3),
getpid(3),
<a href="../../api_c/DbLog/put.html">log_put</a>,
malloc(3),
memcpy(3),
memset(3),
strerror(3),
vfprintf(3),
and
vsnprintf(3).
<p>
<h1>See Also</h1>
<a href="../../api_c/DbTxn/abort.html">txn_abort</a>,
<a href="../../api_c/DbTxnMgr/begin.html">txn_begin</a>,
<a href="../../api_c/DbTxnMgr/checkpoint.html">txn_checkpoint</a>,
<a href="../../api_c/DbTxnMgr/close.html">txn_close</a>,
<a href="../../api_c/DbTxn/commit.html">txn_commit</a>,
<a href="../../api_c/DbTxn/id.html">txn_id</a>,
<a href="../../api_c/DbTxnMgr/open.html">txn_open</a>,
txn_prepare,
<a href="../../api_c/DbTxnMgr/stat.html">txn_stat</a>
and
<a href="../../api_c/DbTxnMgr/unlink.html">txn_unlink</a>.
</tt>
</body>
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