<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html><head><meta name="robots" content="noindex"> <meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> <title>SharedFile class Reference</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> </head><body bgcolor="#ffffff"> <!-- Generated by Doxygen 1.2.5 on Thu Oct 4 15:33:01 2001 --> <center> <a class="qindex" href="index.html">Main Page</a> <a class="qindex" href="hierarchy.html">Class Hierarchy</a> <a class="qindex" href="classes.html">Alphabetical List</a> <a class="qindex" href="annotated.html">Compound List</a> <a class="qindex" href="files.html">File List</a> <a class="qindex" href="functions.html">Compound Members</a> <a class="qindex" href="globals.html">File Members</a> </center> <hr><h1>SharedFile Class Reference</h1>This class defines a database I/O file service that can be shared by multiple processes. This class defines a database I/O file service that can be shared by multiple processes. <a href="#_details">More...</a> <p> <code>#include <<a class="el" href="file_h-source.html">file.h</a>></code> <p> <p>Inheritance diagram for SharedFile: <p><center><img src="class_sharedfile.gif" usemap="#SharedFile_map" border="0"></center> <map name="SharedFile_map"> <area href="class_randomfile.html" alt="RandomFile" shape="rect" coords="0,56,78,80"> <area href="class_mutex.html" alt="Mutex" shape="rect" coords="0,0,78,24"> </map> <a href="class_sharedfile-members.html">List of all members.</a><table border=0 cellpadding=0 cellspacing=0> <tr><td colspan=2><br><h2>Public Methods</h2></td></tr> <tr><td nowrap align=right valign=top> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a0">SharedFile</a> (const char *path)</td></tr> <tr><td> </td><td><font size=-1><em>Open or create a new database file.</em> <a href="#a0">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a1">SharedFile</a> (const SharedFile &file)</td></tr> <tr><td> </td><td><font size=-1><em>Create a shared file as a duplicate of an existing shared file.</em> <a href="#a1">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a2">~SharedFile</a> ()</td></tr> <tr><td> </td><td><font size=-1><em>Close and finish a database file.</em></font><br><br></td></tr> <tr><td nowrap align=right valign=top><a class="el" href="file_h.html#a39">fileerror_t</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a3">Restart</a> (void)</td></tr> <tr><td> </td><td><font size=-1><em>Restart an existing database; close and re-open.</em> <a href="#a3">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top><a class="el" href="file_h.html#a39">fileerror_t</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a4">Fetch</a> (caddr_t address=NULL, size_t length=0, off_t position=-1)</td></tr> <tr><td> </td><td><font size=-1><em>Lock and Fetch a portion of the file into physical memory.</em> <a href="#a4">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top><a class="el" href="file_h.html#a39">fileerror_t</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a5">Update</a> (caddr_t address=NULL, size_t length=0, off_t position=-1)</td></tr> <tr><td> </td><td><font size=-1><em>Update a portion of a file from physical memory.</em> <a href="#a5">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top><a class="el" href="file_h.html#a39">fileerror_t</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a6">Clear</a> (size_t length=0, off_t pos=-1)</td></tr> <tr><td> </td><td><font size=-1><em>Clear a lock held from a previous fetch operation without updating.</em> <a href="#a6">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top><a class="el" href="file_h.html#a39">fileerror_t</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a7">Append</a> (caddr_t address=NULL, size_t length=0)</td></tr> <tr><td> </td><td><font size=-1><em>Add new data to the end of the file.</em> <a href="#a7">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top>off_t </td><td valign=bottom><a class="el" href="class_sharedfile.html#a8">getPosition</a> (void)</td></tr> <tr><td> </td><td><font size=-1><em>Fetch the current file position marker for this thread.</em> <a href="#a8">More...</a><em></em></font><br><br></td></tr> <tr><td nowrap align=right valign=top><a class="el" href="config_h.html#a17">bool</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a9">operator++</a> (void)</td></tr> <tr><td nowrap align=right valign=top><a class="el" href="config_h.html#a17">bool</a> </td><td valign=bottom><a class="el" href="class_sharedfile.html#a10">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 processes. This class defines a database I/O file service that can be shared by multiple processes. <p> Each thread should access a dup of the database object, and mutex locks can be used to preserve transaction integrety if multiple threads are used. <p> SharedFile is used when a database may be shared between multiple processes. SharedFile automatically applies low level byte-range "file locks", and provides an interface to fetch and release byte-range locked portions of a file. <p> <dl compact><dt> <b>Author(s): </b><dd> David Sugar <<a href="mailto:dyfet@ostel.com">dyfet@ostel.com</a>> </dl> <p> <hr><h2>Constructor & Destructor Documentation</h2> <a name="a0" doxytag="SharedFile::SharedFile"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> SharedFile::SharedFile ( </b></td> <td valign="bottom"><b> const char * <em>path</em> ) </b></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.<dl compact><dt> <b>Parameters: </b><dd> <table border=0 cellspacing=2 cellpadding=0> <tr><td valign=top><em>pathname</em> </td><td> of database to open. </td></tr> <tr><td valign=top><em>file</em> </td><td> access mode. </td></tr> </table> </dl> </td> </tr> </table> <a name="a1" doxytag="SharedFile::SharedFile"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> SharedFile::SharedFile ( </b></td> <td valign="bottom"><b> const SharedFile & <em>file</em> ) </b></td> </tr> </table> </td> </tr> </table> <table cellspacing=5 cellpadding=0 border=0> <tr> <td> </td> <td> <p> Create a shared file as a duplicate of an existing shared file. <p> <dl compact><dt> <b>Parameters: </b><dd> <table border=0 cellspacing=2 cellpadding=0> <tr><td valign=top><em>original</em> </td><td> file. </td></tr> </table> </dl> </td> </tr> </table> <a name="a2" doxytag="SharedFile::~SharedFile"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> SharedFile::~SharedFile ( </b></td> <td valign="bottom"><b> ) </b></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 name="a7" doxytag="SharedFile::Append"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="file_h.html#a39">fileerror_t</a> SharedFile::Append ( </b></td> <td valign="bottom"><b> caddr_t <em>address</em> = NULL, </b></td> </tr> <tr> <td></td> <td><b> size_t <em>length</em> = 0 ) </b></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> Locks file during append.<dl compact><dt> <b>Parameters: </b><dd> <table border=0 cellspacing=2 cellpadding=0> <tr><td valign=top><em>address</em> </td><td> to use, or NULL if same as last I/O. </td></tr> <tr><td valign=top><em>length</em> </td><td> to use, or 0 if same as last I/O. </td></tr> </table> </dl> </td> </tr> </table> <a name="a6" doxytag="SharedFile::Clear"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="file_h.html#a39">fileerror_t</a> SharedFile::Clear ( </b></td> <td valign="bottom"><b> size_t <em>length</em> = 0, </b></td> </tr> <tr> <td></td> <td><b> off_t <em>pos</em> = -1 ) </b></td> </tr> </table> </td> </tr> </table> <table cellspacing=5 cellpadding=0 border=0> <tr> <td> </td> <td> <p> Clear a lock held from a previous fetch operation without updating. <p> <dl compact><dt> <b>Returns: </b><dd> FILE_SUCCESS on success. </dl><dl compact><dt> <b>Parameters: </b><dd> <table border=0 cellspacing=2 cellpadding=0> <tr><td valign=top><em>length</em> </td><td> to use, or 0 if same as last I/O. </td></tr> <tr><td valign=top><em>file</em> </td><td> position to use or -1 if same as last I/O. </td></tr> </table> </dl> </td> </tr> </table> <a name="a4" doxytag="SharedFile::Fetch"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="file_h.html#a39">fileerror_t</a> SharedFile::Fetch ( </b></td> <td valign="bottom"><b> caddr_t <em>address</em> = NULL, </b></td> </tr> <tr> <td></td> <td><b> size_t <em>length</em> = 0, </b></td> </tr> <tr> <td></td> <td><b> off_t <em>position</em> = - 1 ) </b></td> </tr> </table> </td> </tr> </table> <table cellspacing=5 cellpadding=0 border=0> <tr> <td> </td> <td> <p> Lock and 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><dd> FILE_SUCCESS on success. </dl><dl compact><dt> <b>Parameters: </b><dd> <table border=0 cellspacing=2 cellpadding=0> <tr><td valign=top><em>address</em> </td><td> to use, or NULL if same as last I/O. </td></tr> <tr><td valign=top><em>length</em> </td><td> to use, or 0 if same as last I/O. </td></tr> <tr><td valign=top><em>file</em> </td><td> position to use -1 if same as last I/O. </td></tr> </table> </dl> </td> </tr> </table> <a name="a3" doxytag="SharedFile::Restart"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="file_h.html#a39">fileerror_t</a> SharedFile::Restart ( </b></td> <td valign="bottom"><b> void )<code> [inline, virtual]</code> </b></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><dd> FILE_SUCCESS if successful. </dl> <p> Reimplemented from <a class="el" href="class_randomfile.html#a3">RandomFile</a>. </td> </tr> </table> <a name="a5" doxytag="SharedFile::Update"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="file_h.html#a39">fileerror_t</a> SharedFile::Update ( </b></td> <td valign="bottom"><b> caddr_t <em>address</em> = NULL, </b></td> </tr> <tr> <td></td> <td><b> size_t <em>length</em> = 0, </b></td> </tr> <tr> <td></td> <td><b> off_t <em>position</em> = -1 ) </b></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. The current lock is also cleared. <p> <dl compact><dt> <b>Returns: </b><dd> FILE_SUCCESS on success. </dl><dl compact><dt> <b>Parameters: </b><dd> <table border=0 cellspacing=2 cellpadding=0> <tr><td valign=top><em>address</em> </td><td> to use, or NULL if same as last I/O. </td></tr> <tr><td valign=top><em>length</em> </td><td> to use, or 0 if same as last I/O. </td></tr> <tr><td valign=top><em>file</em> </td><td> position to use or -1 if same as last I/O. </td></tr> </table> </dl> </td> </tr> </table> <a name="a8" doxytag="SharedFile::getPosition"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> off_t SharedFile::getPosition ( </b></td> <td valign="bottom"><b> void ) </b></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><dd> file position offset. </dl> </td> </tr> </table> <a name="a9" doxytag="SharedFile::operator++"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="config_h.html#a17">bool</a> SharedFile::operator++ ( </b></td> <td valign="bottom"><b> void ) </b></td> </tr> </table> </td> </tr> </table> <table cellspacing=5 cellpadding=0 border=0> <tr> <td> </td> <td> <p> </td> </tr> </table> <a name="a10" doxytag="SharedFile::operator--"></a><p> <table width="100%" cellpadding="2" cellspacing="0" border="0"> <tr> <td class="md"> <table cellpadding="0" cellspacing="0" border="0"> <tr> <td nowrap valign="top"><b> <a class="el" href="config_h.html#a17">bool</a> SharedFile::operator-- ( </b></td> <td valign="bottom"><b> void ) </b></td> </tr> </table> </td> </tr> </table> <table cellspacing=5 cellpadding=0 border=0> <tr> <td> </td> <td> <p> </td> </tr> </table> <hr>The documentation for this class was generated from the following file:<ul> <li><a class="el" href="file_h-source.html">file.h</a></ul> <hr><address><small>Generated at Thu Oct 4 15:33:01 2001 for CommonC++ by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.gif" alt="doxygen" align="middle" border=0 width=110 height=53></a>1.2.5 written by <a href="mailto:dimitri@stack.nl">Dimitri van Heesch</a>, © 1997-2001</small></address> </body> </html>