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gerrit-public.fairphone.software / platform / external / libxml2 / 597bc48bab455d2ed0b7896b28066de2f962a0a0 / . / doc / tutorial / ar01s06.html
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MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
MDT 2003 John Fleck8aff3b72003-04-26 03:54:07 +0000[diff] [blame]2<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Writing Attribute</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s05.html" title="Writing element content"><link rel="next" href="ar01s07.html" title="Retrieving Attributes"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Writing Attribute</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s05.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s07.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialwritingattribute"></a>Writing Attribute</h2></div></div><div></div></div><p><a class="indexterm" name="id2814216"></a>
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]3Writing an attribute is similar to writing text to a new element. In
4 this case, we'll add a reference <span class="acronym">URI</span> to our
MDT 2003 John Fleck8aff3b72003-04-26 03:54:07 +0000[diff] [blame]5 document. Full code:<a href="ape.html" title="E. Code for Add Attribute Example">Appendix E, <i>Code for Add Attribute Example</i></a>.</p><p>
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]6 A <tt class="sgmltag-element">reference</tt> is a child of the <tt class="sgmltag-element">story</tt>
7 element, so finding the place to put our new element and attribute is
8 simple. As soon as we do the error-checking test in our
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]9 <tt class="function">parseDoc</tt>, we are in the right spot to add our
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]10 element. But before we do that, we need to make a declaration using a
MST 2002 John Fleckbd3b4fd2002-11-11 03:41:11 +0000[diff] [blame]11 data type we have not seen yet:
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]12 </p><pre class="programlisting">
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]13 xmlAttrPtr newattr;
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]14 </pre><p>
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]15 We also need an extra xmlNodePtr:
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]16 </p><pre class="programlisting">
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]17 xmlNodePtr newnode;
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]18 </pre><p>
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]19 </p><p>
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]20 The rest of <tt class="function">parseDoc</tt> is the same as before until we
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]21 check to see if our root element is <tt class="sgmltag-element">story</tt>. If it is,
22 then we know we are at the right spot to add our element:
23
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]24 </p><pre class="programlisting">
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]25 <a name="addreferencenode"></a><img src="images/callouts/1.png" alt="1" border="0"> newnode = xmlNewTextChild (cur, NULL, &quot;reference&quot;, NULL);
26 <a name="addattributenode"></a><img src="images/callouts/2.png" alt="2" border="0"> newattr = xmlNewProp (newnode, &quot;uri&quot;, uri);
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]27 </pre><p>
MST 2002 John Fleckbd3b4fd2002-11-11 03:41:11 +0000[diff] [blame]28 </p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#addreferencenode"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>First we add a new node at the location of the current node
MST 2003 John Fleck731967e2003-01-27 00:39:50 +0000[diff] [blame]29 pointer, <tt class="varname">cur.</tt> using the <a href="http://xmlsoft.org/html/libxml-tree.html#XMLNEWTEXTCHILD" target="_top">xmlNewTextChild</a> function.</p></td></tr></table></div><p>
MDT 2002 John Fleck598f6eb2002-06-04 15:10:36 +0000[diff] [blame]30 </p><p>Once the node is added, the file is written to disk just as in the
MDT 2002 John Fleck54520832002-06-13 03:30:26 +0000[diff] [blame]31 previous example in which we added an element with text content.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s05.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s07.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Writing element content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Retrieving Attributes</td></tr></table></div></body></html>