D. XPath例程代碼
#include <libxml/parser.h>
#include <libxml/xpath.h>

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);
  result = xmlXPathEvalExpression(xpath, context);
  if(xmlXPathNodeSetIsEmpty(result->nodesetval)){
    printf("No result\n");
    return NULL;
  }
  xmlXPathFreeContext(context);
  return result;
}

int
main(int argc, char **argv) {
  char *docname;
  xmlDocPtr doc;
  xmlChar *xpath = ("http://keyword");
  xmlNodeSetPtr nodeset;
  xmlXPathObjectPtr result;
  int i;
  xmlChar *keyword;
  if (argc <= 1) {
    printf("Usage: %s docname\n", argv[0]);
    return(0);
  }
  docname = argv[1];
  doc = getdoc(docname);
  result = getnodeset (doc, xpath);
  if (result) {
    nodeset = result->nodesetval;
    for (i=0; i < nodeset->nodeNr; i++) {
      keyword = xmlNodeListGetString(doc, nodeset->nodeTab[i]->printf
         ("keyword: %s\n", keyword);
         xmlFree(keyword);
         } 
         xmlXPathFreeObject (result);
    }
    xmlFreeDoc(doc);
    xmlCleanupParser();
    return (1); 
}

E. 添加keyword例程代碼
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h> 

void 
parseStory (xmlDocPtr doc, xmlNodePtr cur, char *keyword) {
    xmlNewTextChild (cur, NULL, "keyword", keyword);
    return;
  }

xmlDocPtr 
parseDoc(char *docname, char *keyword) {
    xmlDocPtr doc;
    xmlNodePtr cur;
    doc = xmlParseFile(docname);
    if (doc == NULL ) {
      fprintf(stderr,"Document not parsed successfully. \n");
      return (NULL);
    }
    cur = xmlDocGetRootElement(doc);
    if (cur == NULL) {
      fprintf(stderr,"empty document\n");
      xmlFreeDoc(doc);
      return (NULL);
    }
    if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
      fprintf(stderr,"document of the wrong type, root node != story");
      xmlFreeDoc(doc);
      return (NULL);
    }
    cur = cur->xmlChildrenNode;
    while (cur != NULL) {
      if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
        parseStory (doc, cur, keyword);
      }
      cur = cur->next;
    }
    return(doc);
}

int
main(int argc, char **argv) {
    char *docname;
    char *keyword;
    xmlDocPtr doc;
    if (argc <= 2) {
      printf("Usage: %s docname, keyword\n", argv[0]);
      return(0);
    }
    docname = argv[1];
    keyword = argv[2];
    doc = parseDoc (docname, keyword);
    if (doc != NULL) {
      xmlSaveFormatFile (docname, doc, 0);
      xmlFreeDoc(doc);
    }
    return (1);
}

F. 添加屬性例程代碼
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h>

xmlDocPtr
parseDoc(char *docname, char *uri) {
    xmlDocPtr doc;
    xmlNodePtr cur;
    xmlNodePtr newnode;
    xmlAttrPtr newattr;
    doc = xmlParseFile(docname);
    if (doc == NULL ) {
      fprintf(stderr,"Document not parsed successfully. \n");
      return (NULL);
    }
    cur = xmlDocGetRootElement(doc);
    if (cur == NULL) {
      fprintf(stderr,"empty document\n");
      xmlFreeDoc(doc);
      return (NULL);
    }
    if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
      fprintf(stderr,"document of the wrong type, root node != story");
      xmlFreeDoc(doc);
      return (NULL);
    }
    newnode = xmlNewTextChild (cur, NULL, "reference", NULL);
    newattr = xmlNewProp (newnode, "uri", uri);
    return(doc);
}

int
main(int argc, char **argv) {
    char *docname;
    char *uri;
    xmlDocPtr doc;
    if (argc <= 2) {
      printf("Usage: %s docname, uri\n", argv[0]);
      return(0);
    }
    docname = argv[1];
    uri = argv[2];
    doc = parseDoc (docname, uri);
    if (doc != NULL) {
      xmlSaveFormatFile (docname, doc, 1);
      xmlFreeDoc(doc);
    }
    return (1);
}

G. 取得屬性值例程代碼
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h>

void
getReference (xmlDocPtr doc, xmlNodePtr cur) {
  xmlChar *uri;
  cur = cur->xmlChildrenNode;
  while (cur != NULL) {
    if ((!xmlStrcmp(cur->name, (const xmlChar *)"reference"))) {
      uri = xmlGetProp(cur, "uri");
      printf("uri: %s\n", uri);
      xmlFree(uri);
    }
    cur = cur->next;
  }
  return;
}

void
parseDoc(char *docname) {
  xmlDocPtr doc;
  xmlNodePtr cur;
  doc = xmlParseFile(docname);
  if (doc == NULL ) {
    fprintf(stderr,"Document not parsed successfully. \n");
    return;
  }
  cur = xmlDocGetRootElement(doc);
  if (cur == NULL) {
    fprintf(stderr,"empty document\n");
    xmlFreeDoc(doc);
    return;
  }  
  if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
    fprintf(stderr,"document of the wrong type, root node != story");
    xmlFreeDoc(doc);
    return;
  }
  getReference (doc, cur);
  xmlFreeDoc(doc);
  return;
}

int
main(int argc, char **argv) {
  char *docname;
  if (argc <= 1) {
    printf("Usage: %s docname\n", argv[0]);
    return(0);
  }
  docname = argv[1];
  parseDoc (docname);
  return (1);
}

H. 編碼轉(zhuǎn)換例程代碼
#include <string.h>
#include <libxml/parser.h>

unsigned char*
convert (unsigned char *in, char *encoding) {
  unsigned char *out;
  int ret,size,out_size,temp;
  xmlCharEncodingHandlerPtr handler;
  size = (int)strlen(in)+1;
  out_size = size*2-1;
  out = malloc((size_t)out_size);
  if (out) {
    handler = xmlFindCharEncodingHandler(encoding);
    if (!handler) {
      free(out);
      out = NULL;
    }
  }
  if (out) {
    temp=size-1;
    ret = handler->input(out, &out_size, in, &temp);
    if (ret || temp-size+1) {
      if (ret) {  
        printf("conversion wasn't successful.\n");
      } else {
        printf("conversion wasn't successful. converted:");
      }
      free(out);
      out = NULL;
    } else {
      out = realloc(out,out_size+1);
      out[out_size]=0; /*null terminating out*/
    }
  } else {
    printf("no mem\n");
  }
  return (out);
}

int
main(int argc, char **argv) {
  unsigned char *content, *out;
  xmlDocPtr doc;
  xmlNodePtr rootnode;
  char *encoding = "ISO-8859-1";
  if (argc <= 1) {
    printf("Usage: %s content\n", argv[0]);
    return(0);
  }
  content = argv[1];
  out = convert(content, encoding);
  doc = xmlNewDoc ("1.0");
  rootnode = xmlNewDocNode(doc, NULL, (const xmlChar*)"root", out);
  xmlDocSetRootElement(doc, rootnode);
  xmlSaveFormatFileEnc("-", doc, encoding, 1);
  return (1);
}

char *convert(char *instr,char *encoding) {
  xmlCharEncodingHandlerPtr handler;
  xmlBufferPtr in,out;
  handler = xmlFindCharEncodingHandler(encoding);
  if(NULL != handler) {
    in = xmlBufferCreate();
    xmlBufferWriteChar(in,instr);
    out = xmlBufferCreate();
    if(xmlCharEncInFunc(handler, out, in) 〈 0) {
       xmlBufferFree(in);
       xmlBufferFree(out);
       return NULL;
      }
      else {
        xmlBufferFree(in);
        return (char *)out-〉content;
      }
  }
}