1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>DB_ENV->set_isalive()</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> 10 <link rel="up" href="env.html" title="Chapter��5.�� The DB_ENV Handle" /> 11 <link rel="prev" href="envset_intermediate_dir_mode.html" title="DB_ENV->set_intermediate_dir_mode()" /> 12 <link rel="next" href="envset_msgcall.html" title="DB_ENV->set_msgcall()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DB_ENV->set_isalive()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="envset_intermediate_dir_mode.html">Prev</a>��</td> 22 <th width="60%" align="center">Chapter��5.�� 23 The DB_ENV Handle 24 </th> 25 <td width="20%" align="right">��<a accesskey="n" href="envset_msgcall.html">Next</a></td> 26 </tr> 27 </table> 28 <hr /> 29 </div> 30 <div class="sect1" lang="en" xml:lang="en"> 31 <div class="titlepage"> 32 <div> 33 <div> 34 <h2 class="title" style="clear: both"><a id="envset_isalive"></a>DB_ENV->set_isalive()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db.h> 39 40int 41DB_ENV->set_isalive(DB_ENV *dbenv, int (*is_alive)(DB_ENV *dbenv, 42 pid_t pid, db_threadid_t tid, u_int32_t flags)); </pre> 43 <p> 44 Declare a function that returns if a thread of control (either a true 45 thread or a process) is still running. The <code class="methodname">DB_ENV->set_isalive()</code> 46 method supports the <a class="xref" href="envfailchk.html" title="DB_ENV->failchk()">DB_ENV->failchk()</a> method. 47 For more information, see 48 <a href="../../programmer_reference/cam_app.html" class="olink">Architecting Data Store and Concurrent 49 Data Store applications</a>, and 50 <a href="../../programmer_reference/transapp_app.html" class="olink">Architecting Transactional Data Store 51 applications</a>, both in the <em class="citetitle">Berkeley DB Programmer's Reference Guide</em>. 52 </p> 53 <p> 54 The <code class="methodname">DB_ENV->set_isalive()</code> method configures operations performed 55 using the specified <a class="link" href="env.html" title="Chapter��5.�� The DB_ENV Handle">DB_ENV</a> handle, not all 56 operations performed on the underlying database environment. 57 </p> 58 <p> 59 The <code class="methodname">DB_ENV->set_isalive()</code> method may be called at any time during the 60 life of the application. 61 </p> 62 <p> 63 The <code class="methodname">DB_ENV->set_isalive()</code> <span> 64 <span> 65 method returns a non-zero error value on failure and 0 on success. 66 </span> 67 68 </span> 69 </p> 70 <div class="sect2" lang="en" xml:lang="en"> 71 <div class="titlepage"> 72 <div> 73 <div> 74 <h3 class="title"><a id="id1670912"></a>Parameters</h3> 75 </div> 76 </div> 77 </div> 78 <div class="sect3" lang="en" xml:lang="en"> 79 <div class="titlepage"> 80 <div> 81 <div> 82 <h4 class="title"><a id="id1670945"></a>is_alive</h4> 83 </div> 84 </div> 85 </div> 86 <p> 87 The <span class="bold"><strong>is_alive</strong></span> parameter is a function 88 which returns non-zero if the thread of control, identified by the 89 <span class="bold"><strong>pid</strong></span> and <span class="bold"><strong>tid</strong></span> arguments, is still running. The function 90 takes four arguments: 91 </p> 92 <div class="itemizedlist"> 93 <ul type="disc"> 94 <li> 95 <p> 96 <span class="bold"><strong>dbenv</strong></span> 97 </p> 98 <p> 99 The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing 100 database environment handle, allowing application access to the 101 application-private fields of that object. 102 </p> 103 </li> 104 <li> 105 <p> 106 <span class="bold"><strong>pid</strong></span> 107 </p> 108 <p> 109 The <span class="bold"><strong>pid</strong></span> parameter is a process ID 110 returned by the function specified to the 111 <a class="xref" href="envset_thread_id.html" title="DB_ENV->set_thread_id()">DB_ENV->set_thread_id()</a> 112 method. 113 </p> 114 </li> 115 <li> 116 <p> 117 <span class="bold"><strong>tid</strong></span> 118 </p> 119 <p> 120 The <span class="bold"><strong>tid</strong></span> parameter is a thread ID 121 returned by the function specified to the 122 <a class="xref" href="envset_thread_id.html" title="DB_ENV->set_thread_id()">DB_ENV->set_thread_id()</a> 123 method. 124 </p> 125 </li> 126 <li> 127 <p> 128 <span class="bold"><strong>flags</strong></span> 129 </p> 130 <p> 131 The <span class="bold"><strong>flags</strong></span> parameter must be set to 0 132 or the following value: 133 </p> 134 <div class="itemizedlist"> 135 <ul type="circle"> 136 <li> 137 <p><a id="isalive_DB_MUTEX_PROCESS_ONLY"></a> 138 <code class="literal">DB_MUTEX_PROCESS_ONLY</code> 139 </p> 140 <p> 141 Return only if the process is alive, the thread ID 142 should be ignored. 143 </p> 144 </li> 145 </ul> 146 </div> 147 </li> 148 </ul> 149 </div> 150 </div> 151 </div> 152 <div class="sect2" lang="en" xml:lang="en"> 153 <div class="titlepage"> 154 <div> 155 <div> 156 <h3 class="title"><a id="id1671214"></a>Errors</h3> 157 </div> 158 </div> 159 </div> 160 <p> 161 The <code class="methodname">DB_ENV->set_isalive()</code> <span> 162 <span> 163 method may fail and return one of the following non-zero errors: 164 </span> 165 166 </span> 167 </p> 168 <div class="sect3" lang="en" xml:lang="en"> 169 <div class="titlepage"> 170 <div> 171 <div> 172 <h4 class="title"><a id="id1671346"></a>EINVAL</h4> 173 </div> 174 </div> 175 </div> 176 <p> 177 An invalid flag value or parameter was specified. 178 </p> 179 </div> 180 </div> 181 <div class="sect2" lang="en" xml:lang="en"> 182 <div class="titlepage"> 183 <div> 184 <div> 185 <h3 class="title"><a id="id1670936"></a>Class</h3> 186 </div> 187 </div> 188 </div> 189 <p> 190 <a class="link" href="env.html" title="Chapter��5.�� The DB_ENV Handle">DB_ENV</a> 191 </p> 192 </div> 193 <div class="sect2" lang="en" xml:lang="en"> 194 <div class="titlepage"> 195 <div> 196 <div> 197 <h3 class="title"><a id="id1670978"></a>See Also</h3> 198 </div> 199 </div> 200 </div> 201 <p> 202 <a class="xref" href="env.html#envlist" title="Database Environments and Related Methods">Database Environments and Related Methods</a> 203 </p> 204 </div> 205 </div> 206 <div class="navfooter"> 207 <hr /> 208 <table width="100%" summary="Navigation footer"> 209 <tr> 210 <td width="40%" align="left"><a accesskey="p" href="envset_intermediate_dir_mode.html">Prev</a>��</td> 211 <td width="20%" align="center"> 212 <a accesskey="u" href="env.html">Up</a> 213 </td> 214 <td width="40%" align="right">��<a accesskey="n" href="envset_msgcall.html">Next</a></td> 215 </tr> 216 <tr> 217 <td width="40%" align="left" valign="top">DB_ENV->set_intermediate_dir_mode()��</td> 218 <td width="20%" align="center"> 219 <a accesskey="h" href="index.html">Home</a> 220 </td> 221 <td width="40%" align="right" valign="top">��DB_ENV->set_msgcall()</td> 222 </tr> 223 </table> 224 </div> 225 </body> 226</html> 227