doc = xmlParseFile(pXMLFileName);
       if (doc == NULL ) 
       {
             fprintf(stderr,"XMLParser:Document not parsed successfully. \n");
             retval = -1;
             goto ERROR_RET;
       }
       cur = xmlDocGetRootElement(doc);         // 會得到NodeRoot 節點.
       if (cur == NULL) 
       {
             fprintf(stderr,"XMLParser:Empty document.\n");
             retval = -2;
             goto ERROR_RET;
       }

       //     ...  do something
       parsexml(doc,cur);         // 定義見下面.

    ERROR_RET:
       if(doc != NULL)
           xmlFreeDoc(doc);
       return retval;
    }
   其中,:
   結構xmlNodePtr 定義如下(libxml/tree.h):
    typedef struct _xmlNode xmlNode;
    typedef xmlNode *xmlNodePtr;
    struct _xmlNode {
    void           *_private; /* application data */
    xmlElementType   type; /* type number, must be second ! */
    const xmlChar   *name;      /* the name of the node, or the entity */ 
    struct _xmlNode *children; /* parent->childs link */
    struct _xmlNode *last; /* last child link */
    struct _xmlNode *parent; /* child->parent link */
    struct _xmlNode *next; /* next sibling link  */
    struct _xmlNode *prev; /* previous sibling link  */
    struct _xmlDoc  *doc; /* the containing document */

    /* End of common part */
    xmlNs           *ns;        /* pointer to the associated namespace */
    xmlChar         *content;   /* the content */
    struct _xmlAttr *properties;/* properties list */
    xmlNs           *nsDef;     /* namespace definitions on this node */
    void            *psvi; /* for type/PSVI informations */
    unsigned short   line; /* line number */
    unsigned short   extra; /* extra data for XPath/XSLT */
    };
    我們可以使用節點結構中的指針成員來遍歷xml樹中的各個節點.
    我一般使用遞歸的方式遍歷xml樹:
   int parsexml(xmlDocPtr doc, xmlNodePtr cur)
   {
       while (cur != NULL)
       {
          // do something about every node
           printf("name: %s\n",cur->name);
          {
                //  for example,we get the "ver" attribute of every node
                xmlChar *uri = NULL; 
                uri = xmlGetProp(cur,(const xmlChar *) "ver"); 
                if(uri != NULL)
                {
                  printf("ver: %s\n", uri);
                   xmlFree(uri);
                }
                ;   // ... others