libxml2-2.7.7/doc/tutorial/apd.html

<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>D. Code for XPath Example</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="apc.html" title="C. Code for Keyword Example"><link rel="next" href="ape.html" title="E. Code for Add Keyword Example"></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">D. Code for XPath Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apc.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ape.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="xpathappendix"></a>D. Code for XPath Example</h2></div></div><div></div></div><p>
      </p><pre class="programlisting">
#include &lt;libxml/parser.h&gt;
#include &lt;libxml/xpath.h&gt;

xmlDocPtr
getdoc (char *docname) {
	xmlDocPtr doc;
	doc = xmlParseFile(docname);
	
	if (doc == NULL ) {
		fprintf(stderr,"Document not parsed successfully. \n");
		return NULL;
	}

	return doc;
}

xmlXPathObjectPtr
getnodeset (xmlDocPtr doc, xmlChar *xpath){
	
	xmlXPathContextPtr context;
	xmlXPathObjectPtr result;

	context = xmlXPathNewContext(doc);
	if (context == NULL) {
		printf("Error in xmlXPathNewContext\n");
		return NULL;
	}
	result = xmlXPathEvalExpression(xpath, context);
	xmlXPathFreeContext(context);
	if (result == NULL) {
		printf("Error in xmlXPathEvalExpression\n");
		return NULL;
	}
	if(xmlXPathNodeSetIsEmpty(result-&gt;nodesetval)){
		xmlXPathFreeObject(result);
                printf("No result\n");
		return NULL;
	}
	return result;
}
int
main(int argc, char **argv) {

	char *docname;
	xmlDocPtr doc;
	xmlChar *xpath = (xmlChar*) "//keyword";
	xmlNodeSetPtr nodeset;
	xmlXPathObjectPtr result;
	int i;
	xmlChar *keyword;
		
	if (argc &lt;= 1) {
		printf("Usage: %s docname\n", argv[0]);
		return(0);
	}

	docname = argv[1];
	doc = getdoc(docname);
	result = getnodeset (doc, xpath);
	if (result) {
		nodeset = result-&gt;nodesetval;
		for (i=0; i &lt; nodeset-&gt;nodeNr; i++) {
			keyword = xmlNodeListGetString(doc, nodeset-&gt;nodeTab[i]-&gt;xmlChildrenNode, 1);
		printf("keyword: %s\n", keyword);
		xmlFree(keyword);
		}
		xmlXPathFreeObject (result);
	}
	xmlFreeDoc(doc);
	xmlCleanupParser();
	return (1);
}
</pre><p>
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