<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <title>GNU CommonC++: ost::MappedFile Class Reference</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <link href="doxygen.css" rel="stylesheet" type="text/css"/> </head> <body> <!-- Generated by Doxygen 1.6.3 --> <div class="navigation" id="top"> <div class="tabs"> <ul> <li><a href="index.html"><span>Main Page</span></a></li> <li><a href="namespaces.html"><span>Namespaces</span></a></li> <li class="current"><a href="annotated.html"><span>Classes</span></a></li> <li><a href="files.html"><span>Files</span></a></li> <li><a href="examples.html"><span>Examples</span></a></li> </ul> </div> <div class="tabs"> <ul> <li><a href="annotated.html"><span>Class List</span></a></li> <li><a href="classes.html"><span>Class Index</span></a></li> <li><a href="hierarchy.html"><span>Class Hierarchy</span></a></li> <li><a href="functions.html"><span>Class Members</span></a></li> </ul> </div> <div class="navpath"><a class="el" href="namespaceost.html">ost</a>::<a class="el" href="classost_1_1_mapped_file.html">MappedFile</a> </div> </div> <div class="contents"> <h1>ost::MappedFile Class Reference</h1><!-- doxytag: class="ost::MappedFile" --><!-- doxytag: inherits="ost::RandomFile" --> <p>Create and map a disk file into memory. <a href="#_details">More...</a></p> <p><code>#include <<a class="el" href="file_8h_source.html">file.h</a>></code></p> <div class="dynheader"> Inheritance diagram for ost::MappedFile:</div> <div class="dynsection"> <div class="center"> <img src="classost_1_1_mapped_file.png" usemap="#ost::MappedFile_map" alt=""/> <map id="ost::MappedFile_map" name="ost::MappedFile_map"> <area href="classost_1_1_random_file.html" alt="ost::RandomFile" shape="rect" coords="55,56,156,80"/> <area href="classost_1_1_mutex.html" alt="ost::Mutex" shape="rect" coords="0,0,101,24"/> <area href="classost_1_1_file.html" alt="ost::File" shape="rect" coords="111,0,212,24"/> </map> </div> </div> <p><a href="classost_1_1_mapped_file-members.html">List of all members.</a></p> <table border="0" cellpadding="0" cellspacing="0"> <tr><td colspan="2"><h2>Public Member Functions</h2></td></tr> <tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a1d8d79711c6d0874ef50f0fee1d768ee">MappedFile</a> (const char *fname, <a class="el" href="classost_1_1_file.html#af371cd81457b88328c08c4501f5e8271">Access</a> mode)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Open a file for mapping. <a href="#a1d8d79711c6d0874ef50f0fee1d768ee"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a65b2b05ede145124ba7d903f2c118b28">MappedFile</a> (const char *fname, <a class="el" href="classost_1_1_file.html#af371cd81457b88328c08c4501f5e8271">Access</a> mode, size_t size)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Create if not exists, and map a file of specified size into memory. <a href="#a65b2b05ede145124ba7d903f2c118b28"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#adbf54b1e56999a84f4a017d0c9b82405">MappedFile</a> (const char *fname, <a class="el" href="namespaceost.html#a4bb988be58c6264b160ef2d6ceb178e5">pos_t</a> offset, size_t size, <a class="el" href="classost_1_1_file.html#af371cd81457b88328c08c4501f5e8271">Access</a> mode)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Map a portion or all of a specified file in the specified shared memory access mode. <a href="#adbf54b1e56999a84f4a017d0c9b82405"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">virtual </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a349f9927a4bfe1106955f1d44959ab2b">~MappedFile</a> ()</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Release a mapped section of memory associated with a file. <a href="#a349f9927a4bfe1106955f1d44959ab2b"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#af5fe36ccac8879fd2ca8b63574686cac">sync</a> (void)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Synchronize the contents of the mapped portion of memory with the disk file and wait for completion. <a href="#af5fe36ccac8879fd2ca8b63574686cac"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a057579ccc63c7e06190abea4bba9a43e">sync</a> (char *address, size_t len)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Synchronize a segment of memory mapped from a segment fetch. <a href="#a057579ccc63c7e06190abea4bba9a43e"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a99b20ddc2524e8ec1ce544d362e786b3">update</a> (size_t offset=0, size_t len=0)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Map a portion of the memory mapped from the file back to the file and do not wait for completion. <a href="#a99b20ddc2524e8ec1ce544d362e786b3"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a6fd5874fd9ffe5f058775b3d34a95064">update</a> (char *address, size_t len)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Update a mapped region back to disk as specified by address and length. <a href="#a6fd5874fd9ffe5f058775b3d34a95064"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a58b384efa39d1fc1d8833974209de206">release</a> (char *address, size_t len)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Release (unmap) a memory segment. <a href="#a58b384efa39d1fc1d8833974209de206"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">char * </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a0d8be211f29d23d39051a86512dee853">fetch</a> (size_t offset=0)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Fetch a pointer to an offset within the memory mapped portion of the disk file. <a href="#a0d8be211f29d23d39051a86512dee853"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">char * </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a7c8db51c98075be049e6ae2efc7966c2">fetch</a> (off_t pos, size_t len)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Fetch and map a portion of a disk file to a logical memory block. <a href="#a7c8db51c98075be049e6ae2efc7966c2"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#ab94baac40118fa5c6903ce42109c7903">lock</a> (void)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Lock the currently mapped portion of a file. <a href="#ab94baac40118fa5c6903ce42109c7903"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#a47776d201f8d2f8f9f0288f797e3da4c">unlock</a> (void)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Unlock a locked mapped portion of a file. <a href="#a47776d201f8d2f8f9f0288f797e3da4c"></a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">size_t </td><td class="memItemRight" valign="bottom"><a class="el" href="classost_1_1_mapped_file.html#af6498463d62c3e69d10919f8687b95ea">pageAligned</a> (size_t size)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Compute map size to aligned page boundry. <a href="#af6498463d62c3e69d10919f8687b95ea"></a><br/></td></tr> </table> <hr/><a name="_details"></a><h2>Detailed Description</h2> <p>Create and map a disk file into memory. </p> <p>This portable class works under both Posix via mmap and under the win32 API. A mapped file can be referenced directly by it's memory segment. One can map and unmap portions of a file on demand, and update changed memory pages mapped from files immediately through <a class="el" href="classost_1_1_mapped_file.html#af5fe36ccac8879fd2ca8b63574686cac" title="Synchronize the contents of the mapped portion of memory with the disk file and wait...">sync()</a>.</p> <dl class="author"><dt><b>Author:</b></dt><dd>David Sugar <<a href="mailto:dyfet@ostel.com">dyfet@ostel.com</a>> Map a named disk file into memory. </dd></dl> <hr/><h2>Constructor & Destructor Documentation</h2> <a class="anchor" id="a1d8d79711c6d0874ef50f0fee1d768ee"></a><!-- doxytag: member="ost::MappedFile::MappedFile" ref="a1d8d79711c6d0874ef50f0fee1d768ee" args="(const char *fname, Access mode)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">ost::MappedFile::MappedFile </td> <td>(</td> <td class="paramtype">const char * </td> <td class="paramname"> <em>fname</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="classost_1_1_file.html#af371cd81457b88328c08c4501f5e8271">Access</a> </td> <td class="paramname"> <em>mode</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Open a file for mapping. </p> <p>More than one segment of a file may be mapped into seperate regions of memory.</p> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>fname</em> </td><td>file name to access for mapping. </td></tr> <tr><td valign="top"></td><td valign="top"><em>mode</em> </td><td>access mode to map file. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="a65b2b05ede145124ba7d903f2c118b28"></a><!-- doxytag: member="ost::MappedFile::MappedFile" ref="a65b2b05ede145124ba7d903f2c118b28" args="(const char *fname, Access mode, size_t size)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">ost::MappedFile::MappedFile </td> <td>(</td> <td class="paramtype">const char * </td> <td class="paramname"> <em>fname</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="classost_1_1_file.html#af371cd81457b88328c08c4501f5e8271">Access</a> </td> <td class="paramname"> <em>mode</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>size</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Create if not exists, and map a file of specified size into memory. </p> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>fname</em> </td><td>file name to access for mapping. </td></tr> <tr><td valign="top"></td><td valign="top"><em>mode</em> </td><td>access mode to map file. </td></tr> <tr><td valign="top"></td><td valign="top"><em>size</em> </td><td>of file to map. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="adbf54b1e56999a84f4a017d0c9b82405"></a><!-- doxytag: member="ost::MappedFile::MappedFile" ref="adbf54b1e56999a84f4a017d0c9b82405" args="(const char *fname, pos_t offset, size_t size, Access mode)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">ost::MappedFile::MappedFile </td> <td>(</td> <td class="paramtype">const char * </td> <td class="paramname"> <em>fname</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="namespaceost.html#a4bb988be58c6264b160ef2d6ceb178e5">pos_t</a> </td> <td class="paramname"> <em>offset</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>size</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="classost_1_1_file.html#af371cd81457b88328c08c4501f5e8271">Access</a> </td> <td class="paramname"> <em>mode</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Map a portion or all of a specified file in the specified shared memory access mode. </p> <p>Valid mapping modes include mappedRead, mappedWrite, and mappedReadWrite.</p> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>fname</em> </td><td>pathname of file to map into memory. </td></tr> <tr><td valign="top"></td><td valign="top"><em>offset</em> </td><td>from start of file to begin mapping in bytes. </td></tr> <tr><td valign="top"></td><td valign="top"><em>size</em> </td><td>of mapped area in bytes. </td></tr> <tr><td valign="top"></td><td valign="top"><em>mode</em> </td><td>to map file. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="a349f9927a4bfe1106955f1d44959ab2b"></a><!-- doxytag: member="ost::MappedFile::~MappedFile" ref="a349f9927a4bfe1106955f1d44959ab2b" args="()" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">virtual ost::MappedFile::~MappedFile </td> <td>(</td> <td class="paramname"></td> <td> ) </td> <td><code> [virtual]</code></td> </tr> </table> </div> <div class="memdoc"> <p>Release a mapped section of memory associated with a file. </p> <p>The mapped area is updated back to disk. </p> </div> </div> <hr/><h2>Member Function Documentation</h2> <a class="anchor" id="a7c8db51c98075be049e6ae2efc7966c2"></a><!-- doxytag: member="ost::MappedFile::fetch" ref="a7c8db51c98075be049e6ae2efc7966c2" args="(off_t pos, size_t len)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">char* ost::MappedFile::fetch </td> <td>(</td> <td class="paramtype">off_t </td> <td class="paramname"> <em>pos</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>len</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Fetch and map a portion of a disk file to a logical memory block. </p> <dl class="return"><dt><b>Returns:</b></dt><dd>pointer to memory segment. </dd></dl> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>pos</em> </td><td>offset of file segment to map. </td></tr> <tr><td valign="top"></td><td valign="top"><em>len</em> </td><td>size of memory segment to map. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="a0d8be211f29d23d39051a86512dee853"></a><!-- doxytag: member="ost::MappedFile::fetch" ref="a0d8be211f29d23d39051a86512dee853" args="(size_t offset=0)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">char* ost::MappedFile::fetch </td> <td>(</td> <td class="paramtype">size_t </td> <td class="paramname"> <em>offset</em> = <code>0</code></td> <td> ) </td> <td><code> [inline]</code></td> </tr> </table> </div> <div class="memdoc"> <p>Fetch a pointer to an offset within the memory mapped portion of the disk file. </p> <p>This really is used for convience of matching operations between Update and Fetch, as one could simply have accessed the base pointer where the file was mapped directly.</p> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>offset</em> </td><td>from start of mapped memory. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="ab94baac40118fa5c6903ce42109c7903"></a><!-- doxytag: member="ost::MappedFile::lock" ref="ab94baac40118fa5c6903ce42109c7903" args="(void)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">bool ost::MappedFile::lock </td> <td>(</td> <td class="paramtype">void </td> <td class="paramname"></td> <td> ) </td> <td></td> </tr> </table> </div> <div class="memdoc"> <p>Lock the currently mapped portion of a file. </p> <dl class="return"><dt><b>Returns:</b></dt><dd>true if pages are locked. </dd></dl> </div> </div> <a class="anchor" id="af6498463d62c3e69d10919f8687b95ea"></a><!-- doxytag: member="ost::MappedFile::pageAligned" ref="af6498463d62c3e69d10919f8687b95ea" args="(size_t size)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">size_t ost::MappedFile::pageAligned </td> <td>(</td> <td class="paramtype">size_t </td> <td class="paramname"> <em>size</em></td> <td> ) </td> <td></td> </tr> </table> </div> <div class="memdoc"> <p>Compute map size to aligned page boundry. </p> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>size</em> </td><td>request. </td></tr> </table> </dd> </dl> <dl class="return"><dt><b>Returns:</b></dt><dd>page aligned size. </dd></dl> </div> </div> <a class="anchor" id="a58b384efa39d1fc1d8833974209de206"></a><!-- doxytag: member="ost::MappedFile::release" ref="a58b384efa39d1fc1d8833974209de206" args="(char *address, size_t len)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void ost::MappedFile::release </td> <td>(</td> <td class="paramtype">char * </td> <td class="paramname"> <em>address</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>len</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Release (unmap) a memory segment. </p> <dl><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 of memory segment to release. </td></tr> <tr><td valign="top"></td><td valign="top"><em>len</em> </td><td>length of memory segment to release. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="a057579ccc63c7e06190abea4bba9a43e"></a><!-- doxytag: member="ost::MappedFile::sync" ref="a057579ccc63c7e06190abea4bba9a43e" args="(char *address, size_t len)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void ost::MappedFile::sync </td> <td>(</td> <td class="paramtype">char * </td> <td class="paramname"> <em>address</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>len</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Synchronize a segment of memory mapped from a segment fetch. </p> <dl><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>memory address to update. </td></tr> <tr><td valign="top"></td><td valign="top"><em>len</em> </td><td>size of segment. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="af5fe36ccac8879fd2ca8b63574686cac"></a><!-- doxytag: member="ost::MappedFile::sync" ref="af5fe36ccac8879fd2ca8b63574686cac" args="(void)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void ost::MappedFile::sync </td> <td>(</td> <td class="paramtype">void </td> <td class="paramname"></td> <td> ) </td> <td></td> </tr> </table> </div> <div class="memdoc"> <p>Synchronize the contents of the mapped portion of memory with the disk file and wait for completion. </p> <p>This assures the memory mapped from the file is written back. </p> </div> </div> <a class="anchor" id="a47776d201f8d2f8f9f0288f797e3da4c"></a><!-- doxytag: member="ost::MappedFile::unlock" ref="a47776d201f8d2f8f9f0288f797e3da4c" args="(void)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void ost::MappedFile::unlock </td> <td>(</td> <td class="paramtype">void </td> <td class="paramname"></td> <td> ) </td> <td></td> </tr> </table> </div> <div class="memdoc"> <p>Unlock a locked mapped portion of a file. </p> </div> </div> <a class="anchor" id="a6fd5874fd9ffe5f058775b3d34a95064"></a><!-- doxytag: member="ost::MappedFile::update" ref="a6fd5874fd9ffe5f058775b3d34a95064" args="(char *address, size_t len)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void ost::MappedFile::update </td> <td>(</td> <td class="paramtype">char * </td> <td class="paramname"> <em>address</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>len</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Update a mapped region back to disk as specified by address and length. </p> <dl><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 of segment. </td></tr> <tr><td valign="top"></td><td valign="top"><em>len</em> </td><td>length of segment. </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="a99b20ddc2524e8ec1ce544d362e786b3"></a><!-- doxytag: member="ost::MappedFile::update" ref="a99b20ddc2524e8ec1ce544d362e786b3" args="(size_t offset=0, size_t len=0)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void ost::MappedFile::update </td> <td>(</td> <td class="paramtype">size_t </td> <td class="paramname"> <em>offset</em> = <code>0</code>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">size_t </td> <td class="paramname"> <em>len</em> = <code>0</code></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Map a portion of the memory mapped from the file back to the file and do not wait for completion. </p> <p>This is useful when mapping a database file and updating a single record.</p> <dl><dt><b>Parameters:</b></dt><dd> <table border="0" cellspacing="2" cellpadding="0"> <tr><td valign="top"></td><td valign="top"><em>offset</em> </td><td>offset into the mapped region of memory. </td></tr> <tr><td valign="top"></td><td valign="top"><em>len</em> </td><td>length of partial region (example, record length). </td></tr> </table> </dd> </dl> </div> </div> <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></li> </ul> </div> <hr class="footer"/><address style="text-align: right;"><small>Generated on Fri Nov 12 09:55:47 2010 for GNU CommonC++ by <a href="http://www.doxygen.org/index.html"> <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.6.3 </small></address> </body> </html>