1<!--$Id: env_cdsgroup_begin.so,v 1.3 2008/04/09 20:31:41 sarette Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: DbEnv::cdsgroup_begin</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>DbEnv::cdsgroup_begin</b> 14</td> 15<td align=right> 16<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a> 17<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db_cxx.h> 23<p> 24int 25DbEnv::cdsgroup_begin(DbTxn **tid); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: DbEnv::cdsgroup_begin</b> 29<a name="2"><!--meow--></a> 30<p>The DbEnv::cdsgroup_begin method allocates a locker ID in an 31environment configured for Berkeley DB Concurrent Data Store applications. It copies a pointer to 32a <a href="../api_cxx/txn_class.html">DbTxn</a> that uniquely identifies the locker ID into the memory 33to which <b>tid</b> refers. Calling the <a href="../api_cxx/txn_commit.html">DbTxn::commit</a> method will 34discard the allocated locker ID.</p> 35<p>See <a href="../ref/cam/intro.html">Berkeley DB Concurrent Data Store applications</a> for more 36information about when this is required.</p> 37<p>The DbEnv::cdsgroup_begin method may be called at any time during the life of the 38application.</p> 39<p>The DbEnv::cdsgroup_begin method 40either returns a non-zero error value 41or throws an exception that encapsulates a non-zero error value on 42failure, and returns 0 on success. 43</p> 44<br><b>Errors</b> 45<p>If the maximum number of lockers has been reached, the DbEnv::cdsgroup_begin method will fail and 46either return ENOMEM or 47throw a DbMemoryException.</p> 48<hr size=1 noshade> 49<br><b>Class</b> 50<a href="../api_cxx/env_class.html">DbEnv</a>, <a href="../api_cxx/txn_class.html">DbTxn</a> 51<br><b>See Also</b> 52<a href="../api_cxx/txn_list.html">Transaction Subsystem and Related Methods</a> 53</tt> 54<table width="100%"><tr><td><br></td><td align=right> 55<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 56</td></tr></table> 57<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 58</body> 59</html> 60