58 lines
2.2 KiB
HTML
58 lines
2.2 KiB
HTML
<!--$Id: db_fd.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::fd</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::fd</b>
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</td>
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<td align=right>
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<a href="../api_cxx/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_cxx.h>
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<p>
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int
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Db::fd(int *fdp);
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</pre></b>
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<hr size=1 noshade>
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<b>Description: Db::fd</b>
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<p>The Db::fd method provides access to a file descriptor representative
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of the underlying database. A file descriptor referring to the same
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file will be returned to all processes that call <a href="../api_cxx/db_open.html">Db::open</a> with
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the same <b>file</b> parameter.</p>
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<p>This file descriptor may be safely used as a parameter to the
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<b>fcntl</b>(2) and <b>flock</b>(2) locking functions.</p>
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<p>The Db::fd method only supports a coarse-grained form of locking.
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Applications should instead use the Berkeley DB lock manager where possible.</p>
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<p>The Db::fd method
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either returns a non-zero error value
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or throws an exception that encapsulates a non-zero error value on
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failure, and returns 0 on success.
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</p>
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<b>Parameters</b> <br>
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<b>fdp</b><ul compact><li>The <b>fdp</b> parameter references memory into which
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the current file descriptor is copied.</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_cxx/db_class.html">Db</a>
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<br><b>See Also</b>
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<a href="../api_cxx/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_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>
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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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