82 lines
4.2 KiB
HTML
82 lines
4.2 KiB
HTML
<!--$Id: db_set_errcall.html 63573 2008-05-23 21:43:21Z trent.nelson $-->
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<!--$Id: db_set_errcall.html 63573 2008-05-23 21:43:21Z trent.nelson $-->
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<!--Copyright (c) 1997,2008 Oracle. All rights reserved.-->
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<!--See the file LICENSE for redistribution information.-->
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<html>
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<head>
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<title>Berkeley DB: DB->set_errcall</title>
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<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
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<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++">
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</head>
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<body bgcolor=white>
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<table width="100%"><tr valign=top>
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<td>
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<b>DB->set_errcall</b>
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</td>
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<td align=right>
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<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a>
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<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td>
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</tr></table>
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<hr size=1 noshade>
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<tt>
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<b><pre>
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#include <db.h>
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<p>
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void
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DB->set_errcall(DB *, void (*db_errcall_fcn)
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(const DB_ENV *dbenv, const char *errpfx, const char *msg));
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</pre></b>
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<hr size=1 noshade>
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<b>Description: DB->set_errcall</b>
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<p>When an error occurs in the Berkeley DB library, a Berkeley DB error or an error
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return value is returned by the interface. In some cases, however,
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the <b>errno</b> value may be insufficient to completely describe
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the cause of the error, especially during initial application debugging.</p>
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<p>The <a href="../api_c/env_set_errcall.html">DB_ENV->set_errcall</a> and DB->set_errcall methods are used to
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enhance the mechanism for reporting error messages to the application.
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In some cases, when an error occurs, Berkeley DB will call
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<b>db_errcall_fcn</b> with additional error information. It is up to
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the <b>db_errcall_fcn</b> function to display the error message in an
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appropriate manner.</p>
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<p>Setting <b>db_errcall_fcn</b> to NULL unconfigures the callback interface.</p>
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<p>Alternatively, you can use the <a href="../api_c/db_set_errfile.html">DB->set_errfile</a> or
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<a href="../api_c/env_set_errfile.html">DB_ENV->set_errfile</a> methods to display the additional information via
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a C library FILE *.</p>
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<p>This error-logging enhancement does not slow performance or significantly
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increase application size, and may be run during normal operation as well
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as during application debugging.</p>
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<p>For <a href="../api_c/db_class.html">DB</a> handles opened inside of Berkeley DB environments, calling the
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DB->set_errcall method affects the entire environment and is equivalent to calling
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the <a href="../api_c/env_set_errcall.html">DB_ENV->set_errcall</a> method.</p>
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<p>The DB->set_errcall method configures operations performed using the specified
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<a href="../api_c/db_class.html">DB</a> handle, not all operations performed on the underlying
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database.</p>
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<p>The DB->set_errcall method may be called at any time during the life of the
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application.</p>
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<b>Parameters</b> <br>
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<b>db_errcall_fcn</b><ul compact><li>The <b>db_errcall_fcn</b> parameter is the application-specified error
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reporting function. The function takes three parameters:
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<br>
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<b><b>dbenv</b></b><ul compact><li>The <b>dbenv</b> parameter is the enclosing database environment.</ul>
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<b><b>errpfx</b></b><ul compact><li>The <b>errpfx</b> parameter is the prefix string (as previously set by
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<a href="../api_c/db_set_errpfx.html">DB->set_errpfx</a> or <a href="../api_c/env_set_errpfx.html">DB_ENV->set_errpfx</a>).</ul>
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<b><b>msg</b></b><ul compact><li>The <b>msg</b> parameter is the error message string.</ul>
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<br>
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<p>Berkeley DB is not re-entrant. Callback functions should not attempt to make
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library calls (for example, to release locks or close open handles).
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Re-entering Berkeley DB is not guaranteed to work correctly, and the results
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are undefined.</p></ul>
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<br>
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<hr size=1 noshade>
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<br><b>Class</b>
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<a href="../api_c/db_class.html">DB</a>
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<br><b>See Also</b>
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<a href="../api_c/db_list.html">Databases and Related Methods</a>
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</tt>
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<table width="100%"><tr><td><br></td><td align=right>
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<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a>
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</td></tr></table>
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<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font>
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</body>
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</html>
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