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<a class="el" href="namespaceost.html">ost</a>::<a class="el" href="classost_1_1_thread_file.html">ThreadFile</a></div>
<h1>ost::ThreadFile Class Reference</h1><!-- doxytag: class="ost::ThreadFile" --><!-- doxytag: inherits="ost::RandomFile" -->This class defines a database I/O file service that can be shared by multiple threads.This class defines a database I/O file service that can be shared by multiple threads.
<a href="#_details">More...</a>
<p>
<code>#include <<a class="el" href="file_8h-source.html">file.h</a>></code>
<p>
<p>Inheritance diagram for ost::ThreadFile:
<p><center><img src="classost_1_1_thread_file.png" usemap="#ost::ThreadFile_map" border="0" alt=""></center>
<map name="ost::ThreadFile_map">
<area href="classost_1_1_random_file.html" alt="ost::RandomFile" shape="rect" coords="55,56,155,80">
<area href="classost_1_1_mutex.html" alt="ost::Mutex" shape="rect" coords="0,0,100,24">
<area href="classost_1_1_file.html" alt="ost::File" shape="rect" coords="110,0,210,24">
</map>
<a href="classost_1_1_thread_file-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0">
<tr><td></td></tr>
<tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#17e345a69a04ba5b9db9c556925900c1">ThreadFile</a> (const char *path)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Open or create a new database file. <a href="#17e345a69a04ba5b9db9c556925900c1"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">virtual </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#ebf1b7d1658ad10654425eadd1a34052">~ThreadFile</a> ()</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Close and finish a database file. <a href="#ebf1b7d1658ad10654425eadd1a34052"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#634eeae5f8e783d26e484046344a0556">restart</a> (void)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Restart an existing database; close and re-open. <a href="#634eeae5f8e783d26e484046344a0556"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#3f4dae2704c3780ebccf6abd1f3bc021">fetch</a> (char *address=NULL, <a class="el" href="namespaceost.html#cedd0902cc2709bd066b9f8a2d1f44a0">ccxx_size_t</a> length=0, off_t position=-1)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Fetch a portion of the file into physical memory. <a href="#3f4dae2704c3780ebccf6abd1f3bc021"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#aa50dd7107aa5384b8536316803bcd11">update</a> (char *address=NULL, <a class="el" href="namespaceost.html#cedd0902cc2709bd066b9f8a2d1f44a0">ccxx_size_t</a> length=0, off_t position=-1)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Update a portion of a file from physical memory. <a href="#aa50dd7107aa5384b8536316803bcd11"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#0dd1a865c7936e01f3082b216925f418">append</a> (char *address=NULL, <a class="el" href="namespaceost.html#cedd0902cc2709bd066b9f8a2d1f44a0">ccxx_size_t</a> length=0)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Add new data to the end of the file. <a href="#0dd1a865c7936e01f3082b216925f418"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">off_t </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#09adee0b9978cdc82435c901c850d4e5">getPosition</a> (void)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Fetch the current file position marker for this thread. <a href="#09adee0b9978cdc82435c901c850d4e5"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#5587d9a579902aa4589ec1777fecd2f6">operator++</a> (void)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_thread_file.html#48627c57443c979420e3b218f387cff0">operator--</a> (void)</td></tr>
</table>
<hr><a name="_details"></a><h2>Detailed Description</h2>
This class defines a database I/O file service that can be shared by multiple threads.This class defines a database I/O file service that can be shared by multiple threads.
<p>
All threads access a global copy of the database object, and mutex locks can be used to preserve transaction integrety. pread/pwrite calls can be used for optimized I/O when supported.<p>
<a class="el" href="classost_1_1_thread_file.html">ThreadFile</a> is meant for use by a threaded database server where multiple threads may each perform semi-independent operations on a given database table stored on disk. A special "fcb" structure is used to hold file "state", and pread/pwrite is used whenever possible for optimized I/O. On systems that do not offer pwread/pwrite, a <a class="el" href="classost_1_1_mutex.html">Mutex</a> lock is used to protect concurrent lseek and read/write operations. <a class="el" href="classost_1_1_thread_file.html">ThreadFile</a> managed databases are assumed to be used only by the local server and through a single file descriptor.<p>
<dl compact><dt><b>Author:</b></dt><dd>David Sugar <<a href="mailto:dyfet@ostel.com">dyfet@ostel.com</a>> </dd></dl>
<p>
<hr><h2>Constructor & Destructor Documentation</h2>
<a class="anchor" name="17e345a69a04ba5b9db9c556925900c1"></a><!-- doxytag: member="ost::ThreadFile::ThreadFile" ref="17e345a69a04ba5b9db9c556925900c1" args="(const char *path)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">ost::ThreadFile::ThreadFile </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">const char * </td>
<td class="mdname1" valign="top" nowrap> <em>path</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Open or create a new database file.
<p>
You should also use Initial.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>path</em> </td><td>pathname of database to open. </td></tr>
</table>
</dl>
</td>
</tr>
</table>
<a class="anchor" name="ebf1b7d1658ad10654425eadd1a34052"></a><!-- doxytag: member="ost::ThreadFile::~ThreadFile" ref="ebf1b7d1658ad10654425eadd1a34052" args="()" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">virtual ost::ThreadFile::~ThreadFile </td>
<td class="md" valign="top">( </td>
<td class="mdname1" valign="top" nowrap> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap><code> [virtual]</code></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Close and finish a database file.
<p>
</td>
</tr>
</table>
<hr><h2>Member Function Documentation</h2>
<a class="anchor" name="0dd1a865c7936e01f3082b216925f418"></a><!-- doxytag: member="ost::ThreadFile::append" ref="0dd1a865c7936e01f3082b216925f418" args="(char *address=NULL, ccxx_size_t length=0)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> ost::ThreadFile::append </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">char * </td>
<td class="mdname" nowrap> <em>address</em> = <code>NULL</code>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap><a class="el" href="namespaceost.html#cedd0902cc2709bd066b9f8a2d1f44a0">ccxx_size_t</a> </td>
<td class="mdname" nowrap> <em>length</em> = <code>0</code></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Add new data to the end of the file.
<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>address</em> </td><td>address to use, or NULL if same as last I/O. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>length</em> </td><td>length to use, or 0 if same as last I/O. </td></tr>
</table>
</dl>
</td>
</tr>
</table>
<a class="anchor" name="3f4dae2704c3780ebccf6abd1f3bc021"></a><!-- doxytag: member="ost::ThreadFile::fetch" ref="3f4dae2704c3780ebccf6abd1f3bc021" args="(char *address=NULL, ccxx_size_t length=0, off_t position=-1)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> ost::ThreadFile::fetch </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">char * </td>
<td class="mdname" nowrap> <em>address</em> = <code>NULL</code>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap><a class="el" href="namespaceost.html#cedd0902cc2709bd066b9f8a2d1f44a0">ccxx_size_t</a> </td>
<td class="mdname" nowrap> <em>length</em> = <code>0</code>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>off_t </td>
<td class="mdname" nowrap> <em>position</em> = <code>-1</code></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Fetch a portion of the file into physical memory.
<p>
This can use state information to fetch the current record multiple times.<p>
<dl compact><dt><b>Returns:</b></dt><dd>errSuccess on success. </dd></dl>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>address</em> </td><td>address to use, or NULL if same as last I/O. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>length</em> </td><td>length to use, or 0 if same as last I/O. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>position</em> </td><td>file position to use -1 if same as last I/O. </td></tr>
</table>
</dl>
</td>
</tr>
</table>
<a class="anchor" name="09adee0b9978cdc82435c901c850d4e5"></a><!-- doxytag: member="ost::ThreadFile::getPosition" ref="09adee0b9978cdc82435c901c850d4e5" args="(void)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">off_t ost::ThreadFile::getPosition </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">void </td>
<td class="mdname1" valign="top" nowrap> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Fetch the current file position marker for this thread.
<p>
<dl compact><dt><b>Returns:</b></dt><dd>file position offset. </dd></dl>
</td>
</tr>
</table>
<a class="anchor" name="5587d9a579902aa4589ec1777fecd2f6"></a><!-- doxytag: member="ost::ThreadFile::operator++" ref="5587d9a579902aa4589ec1777fecd2f6" args="(void)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">bool ost::ThreadFile::operator++ </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">void </td>
<td class="mdname1" valign="top" nowrap> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
</td>
</tr>
</table>
<a class="anchor" name="48627c57443c979420e3b218f387cff0"></a><!-- doxytag: member="ost::ThreadFile::operator--" ref="48627c57443c979420e3b218f387cff0" args="(void)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">bool ost::ThreadFile::operator-- </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">void </td>
<td class="mdname1" valign="top" nowrap> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
</td>
</tr>
</table>
<a class="anchor" name="634eeae5f8e783d26e484046344a0556"></a><!-- doxytag: member="ost::ThreadFile::restart" ref="634eeae5f8e783d26e484046344a0556" args="(void)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> ost::ThreadFile::restart </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">void </td>
<td class="mdname1" valign="top" nowrap> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap><code> [virtual]</code></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Restart an existing database; close and re-open.
<p>
<dl compact><dt><b>Returns:</b></dt><dd>errSuccess if successful. </dd></dl>
<p>
Reimplemented from <a class="el" href="classost_1_1_random_file.html#e78c71b1e3fab5861bc9fdae595829a7">ost::RandomFile</a>. </td>
</tr>
</table>
<a class="anchor" name="aa50dd7107aa5384b8536316803bcd11"></a><!-- doxytag: member="ost::ThreadFile::update" ref="aa50dd7107aa5384b8536316803bcd11" args="(char *address=NULL, ccxx_size_t length=0, off_t position=-1)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classost_1_1_file.html#c65e9af20a431154c8d8a811d4c58bde">Error</a> ost::ThreadFile::update </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">char * </td>
<td class="mdname" nowrap> <em>address</em> = <code>NULL</code>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap><a class="el" href="namespaceost.html#cedd0902cc2709bd066b9f8a2d1f44a0">ccxx_size_t</a> </td>
<td class="mdname" nowrap> <em>length</em> = <code>0</code>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>off_t </td>
<td class="mdname" nowrap> <em>position</em> = <code>-1</code></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Update a portion of a file from physical memory.
<p>
This can use state information to commit the last read record.<p>
<dl compact><dt><b>Returns:</b></dt><dd>errSuccess on success. </dd></dl>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>address</em> </td><td>address to use, or NULL if same as last I/O. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>length</em> </td><td>length to use, or 0 if same as last I/O. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>position</em> </td><td>file position to use or -1 if same as last I/O. </td></tr>
</table>
</dl>
</td>
</tr>
</table>
<hr>The documentation for this class was generated from the following file:<ul>
<li><a class="el" href="file_8h-source.html">file.h</a></ul>
<hr size="1"><address style="align: right;"><small>Generated on Mon Jun 19 10:50:56 2006 for GNU CommonC++ by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.6 </small></address>
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