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| </style><title>The SAX interface</title></head><body bgcolor="#8b7765" text="#000000" link="#a06060" vlink="#000000"><table border="0" width="100%" cellpadding="5" cellspacing="0" align="center"><tr><td width="120"><a href="http://swpat.ffii.org/"><img src="epatents.png" alt="Action against software patents" /></a></td><td width="180"><a href="http://www.gnome.org/"><img src="gnome2.png" alt="Gnome2 Logo" /></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C Logo" /></a><a href="http://www.redhat.com/"><img src="redhat.gif" alt="Red Hat Logo" /></a><div align="left"><a href="http://xmlsoft.org/"><img src="Libxml2-Logo-180x168.gif" alt="Made with Libxml2 Logo" /></a></div></td><td><table border="0" width="90%" cellpadding="2" cellspacing="0" align="center" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3" bgcolor="#fffacd"><tr><td align="center"><h1>The XML C parser and toolkit of Gnome</h1><h2>The SAX interface</h2></td></tr></table></td></tr></table></td></tr></table><table border="0" cellpadding="4" cellspacing="0" width="100%" align="center"><tr><td bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td valign="top" width="200" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Developer Menu</b></center></td></tr><tr><td bgcolor="#fffacd"><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="20" value="" /><input name="submit" type="submit" value="Search ..." /></form><ul><li><a href="index.html" style="font-weight:bold">Main Menu</a></li><li><a href="examples/index.html" style="font-weight:bold">Code Examples</a></li><li><a href="guidelines.html">XML Guidelines</a></li><li><a href="tutorial/index.html">Tutorial</a></li><li><a href="xmlreader.html">The Reader Interface</a></li><li><a href="ChangeLog.html">ChangeLog</a></li><li><a href="XSLT.html">XSLT</a></li><li><a href="python.html">Python and bindings</a></li><li><a href="architecture.html">libxml2 architecture</a></li><li><a href="tree.html">The tree output</a></li><li><a href="interface.html">The SAX interface</a></li><li><a href="xmlmem.html">Memory Management</a></li><li><a href="xmlio.html">I/O Interfaces</a></li><li><a href="library.html">The parser interfaces</a></li><li><a href="entities.html">Entities or no entities</a></li><li><a href="namespaces.html">Namespaces</a></li><li><a href="upgrade.html">Upgrading 1.x code</a></li><li><a href="threads.html">Thread safety</a></li><li><a href="DOM.html">DOM Principles</a></li><li><a href="example.html">A real example</a></li><li><a href="xml.html">flat page</a>, <a href="site.xsl">stylesheet</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>API Indexes</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="APIchunk0.html">Alphabetic</a></li><li><a href="APIconstructors.html">Constructors</a></li><li><a href="APIfunctions.html">Functions/Types</a></li><li><a href="APIfiles.html">Modules</a></li><li><a href="APIsymbols.html">Symbols</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="http://mail.gnome.org/archives/xml/">Mail archive</a></li><li><a href="http://xmlsoft.org/XSLT/">XSLT libxslt</a></li><li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li><li><a href="http://www.aleksey.com/xmlsec/">XML-DSig xmlsec</a></li><li><a href="ftp://xmlsoft.org/">FTP</a></li><li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li><li><a href="http://www.blastwave.org/packages.php/libxml2">Solaris binaries</a></li><li><a href="http://www.zveno.com/open_source/libxml2xslt.html">MacOsX binaries</a></li><li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li><li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Bug Tracker</a></li></ul></td></tr></table></td></tr></table></td><td valign="top" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%"><tr><td><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table border="0" cellpadding="3" cellspacing="1" width="100%"><tr><td bgcolor="#fffacd"><p>Sometimes the DOM tree output is just too large to fit reasonably into |
| memory. In that case (and if you don't expect to save back the XML document |
| loaded using libxml), it's better to use the SAX interface of libxml. SAX is |
| a <strong>callback-based interface</strong> to the parser. Before parsing, |
| the application layer registers a customized set of callbacks which are |
| called by the library as it progresses through the XML input.</p><p>To get more detailed step-by-step guidance on using the SAX interface of |
| libxml, see the <a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice |
| documentation</a>.written by <a href="mailto:james@daa.com.au">James |
| Henstridge</a>.</p><p>You can debug the SAX behaviour by using the <strong>testSAX</strong> |
| program located in the gnome-xml module (it's usually not shipped in the |
| binary packages of libxml, but you can find it in the tar source |
| distribution). Here is the sequence of callbacks that would be reported by |
| testSAX when parsing the example XML document shown earlier:</p><pre>SAX.setDocumentLocator() |
| SAX.startDocument() |
| SAX.getEntity(amp) |
| SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp; linux too') |
| SAX.characters( , 3) |
| SAX.startElement(head) |
| SAX.characters( , 4) |
| SAX.startElement(title) |
| SAX.characters(Welcome to Gnome, 16) |
| SAX.endElement(title) |
| SAX.characters( , 3) |
| SAX.endElement(head) |
| SAX.characters( , 3) |
| SAX.startElement(chapter) |
| SAX.characters( , 4) |
| SAX.startElement(title) |
| SAX.characters(The Linux adventure, 19) |
| SAX.endElement(title) |
| SAX.characters( , 4) |
| SAX.startElement(p) |
| SAX.characters(bla bla bla ..., 15) |
| SAX.endElement(p) |
| SAX.characters( , 4) |
| SAX.startElement(image, href='linus.gif') |
| SAX.endElement(image) |
| SAX.characters( , 4) |
| SAX.startElement(p) |
| SAX.characters(..., 3) |
| SAX.endElement(p) |
| SAX.characters( , 3) |
| SAX.endElement(chapter) |
| SAX.characters( , 1) |
| SAX.endElement(EXAMPLE) |
| SAX.endDocument()</pre><p>Most of the other interfaces of libxml2 are based on the DOM tree-building |
| facility, so nearly everything up to the end of this document presupposes the |
| use of the standard DOM tree build. Note that the DOM tree itself is built by |
| a set of registered default callbacks, without internal specific |
| interface.</p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html> |