Annotation of embedaddon/libxml2/doc/tutorial/ar01s03.html, revision 1.1.1.1

1.1       misho       1: <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Parsing the file</title><meta name="generator" content="DocBook XSL Stylesheets V1.61.2"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s02.html" title="Data Types"><link rel="next" href="ar01s04.html" title="Retrieving Element Content"></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">Parsing the file</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s02.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s04.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="xmltutorialparsing"></a>Parsing the file</h2></div></div><div></div></div><p><a class="indexterm" name="fileparsing"></a>
                      2: Parsing the file requires only the name of the file and a single
                      3:       function call, plus error checking. Full code: <a href="apc.html" title="C. Code for Keyword Example">Appendix C, <i>Code for Keyword Example</i></a></p><p>
                      4:     </p><pre class="programlisting">
                      5:         <a name="declaredoc"></a><img src="images/callouts/1.png" alt="1" border="0"> xmlDocPtr doc;
                      6:        <a name="declarenode"></a><img src="images/callouts/2.png" alt="2" border="0"> xmlNodePtr cur;
                      7: 
                      8:        <a name="parsefile"></a><img src="images/callouts/3.png" alt="3" border="0"> doc = xmlParseFile(docname);
                      9:        
                     10:        <a name="checkparseerror"></a><img src="images/callouts/4.png" alt="4" border="0"> if (doc == NULL ) {
                     11:                fprintf(stderr,"Document not parsed successfully. \n");
                     12:                return;
                     13:        }
                     14: 
                     15:        <a name="getrootelement"></a><img src="images/callouts/5.png" alt="5" border="0"> cur = xmlDocGetRootElement(doc);
                     16:        
                     17:        <a name="checkemptyerror"></a><img src="images/callouts/6.png" alt="6" border="0"> if (cur == NULL) {
                     18:                fprintf(stderr,"empty document\n");
                     19:                xmlFreeDoc(doc);
                     20:                return;
                     21:        }
                     22:        
                     23:        <a name="checkroottype"></a><img src="images/callouts/7.png" alt="7" border="0"> if (xmlStrcmp(cur-&gt;name, (const xmlChar *) "story")) {
                     24:                fprintf(stderr,"document of the wrong type, root node != story");
                     25:                xmlFreeDoc(doc);
                     26:                return;
                     27:        }
                     28: 
                     29:     </pre><p>
                     30:       </p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#declaredoc"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>Declare the pointer that will point to your parsed document.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#declarenode"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>Declare a node pointer (you'll need this in order to
                     31:          interact with individual nodes).</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#checkparseerror"><img src="images/callouts/4.png" alt="4" border="0"></a> </td><td valign="top" align="left"><p>Check to see that the document was successfully parsed. If it
                     32:            was not, <span class="application">libxml</span> will at this point
                     33:            register an error and stop. 
                     34:            </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p><a class="indexterm" name="id2525337"></a>
                     35: One common example of an error at this point is improper
                     36:            handling of encoding. The <span class="acronym">XML</span> standard requires
                     37:            documents stored with an encoding other than UTF-8 or UTF-16 to
                     38:            contain an explicit declaration of their encoding. If the
                     39:            declaration is there, <span class="application">libxml</span> will
                     40:            automatically perform the necessary conversion to UTF-8 for
                     41:                you. More information on <span class="acronym">XML's</span> encoding
                     42:                requirements is contained in the <a href="http://www.w3.org/TR/REC-xml#charencoding" target="_top">standard</a>.</p></td></tr></table></div><p>
                     43:          </p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#getrootelement"><img src="images/callouts/5.png" alt="5" border="0"></a> </td><td valign="top" align="left"><p>Retrieve the document's root element.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#checkemptyerror"><img src="images/callouts/6.png" alt="6" border="0"></a> </td><td valign="top" align="left"><p>Check to make sure the document actually contains something.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#checkroottype"><img src="images/callouts/7.png" alt="7" border="0"></a> </td><td valign="top" align="left"><p>In our case, we need to make sure the document is the right
                     44:          type. "story" is the root type of the documents used in this
                     45:          tutorial.</p></td></tr></table></div><p>
                     46:       <a class="indexterm" name="id2525415"></a>
                     47:     </p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s02.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="ar01s04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Data Types </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Retrieving Element Content</td></tr></table></div></body></html>

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