1<!--$Id: env_set_isalive.so,v 10.4 2006/01/27 16:13:48 bostic 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::set_isalive</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::set_isalive</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::set_isalive(int (*is_alive)(DbEnv *dbenv, pid_t pid, db_threadid_t tid, u_int32_t flags)); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: DbEnv::set_isalive</b> 29<p>Declare a function that returns if a thread of control (either a true 30thread or a process) is still running. The DbEnv::set_isalive method 31supports the <a href="../api_cxx/env_failchk.html">DbEnv::failchk</a> method. For more information, see 32<a href="../ref/cam/app.html">Architecting Data Store and Concurrent 33Data Store applications</a>, and <a href="../ref/transapp/app.html">Architecting Transactional Data Store applications</a>.</p> 34<p>The DbEnv::set_isalive method configures operations performed using the specified 35<a href="../api_cxx/env_class.html">DbEnv</a> handle, not all operations performed on the underlying 36database environment.</p> 37<p>The DbEnv::set_isalive method may be called at any time during the life of the 38application.</p> 39<p>The DbEnv::set_isalive 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<b>Parameters</b> <br> 45 <b>is_alive</b><ul compact><li>The <b>is_alive</b> parameter is a function which returns non-zero if 46the thread of control, identified by the <b>pid</b> and <b>tid</b> 47arguments, is still running. The function takes four arguments:</ul> 48<br> 49<b><b>dbenv</b></b><ul compact><li>The <b>dbenv</b> parameter is the enclosing database environment 50handle, allowing application access to the application-private fields 51of that object.</ul> 52<b><b>pid</b></b><ul compact><li>The <b>pid</b> parameter is a process ID returned by the function 53specified to the <a href="../api_cxx/env_set_thread_id.html">DbEnv::set_thread_id</a> method.</ul> 54<b><b>tid</b></b><ul compact><li>The <b>tid</b> parameter is a thread ID returned by the function 55specified to the <a href="../api_cxx/env_set_thread_id.html">DbEnv::set_thread_id</a> method.</ul> 56<b><b>flags</b></b><ul compact><li>The <b>flags</b> parameter must be set to 0 or 57the following value: 58<br> 59<b><a name="DB_MUTEX_PROCESS_ONLY">DB_MUTEX_PROCESS_ONLY</a></b><ul compact><li>Return only if the process is alive, the thread ID should be ignored.</ul> 60<br></ul> 61<br> 62<br> 63<br><b>Errors</b> 64<p>The DbEnv::set_isalive method 65may fail and throw 66<a href="../api_cxx/except_class.html">DbException</a>, 67encapsulating one of the following non-zero errors, or return one of 68the following non-zero errors:</p> 69<br> 70<b>EINVAL</b><ul compact><li>An 71invalid flag value or parameter was specified.</ul> 72<br> 73<hr size=1 noshade> 74<br><b>Class</b> 75<a href="../api_cxx/env_class.html">DbEnv</a> 76<br><b>See Also</b> 77<a href="../api_cxx/env_list.html">Database Environments and Related Methods</a> 78</tt> 79<table width="100%"><tr><td><br></td><td align=right> 80<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> 81</td></tr></table> 82<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 83</body> 84</html> 85
