Re: [xml] Newbie Help

[Daniel Veillard <veillard redhat com>]

On Mon, Aug 09, 2004 at 02:39:10PM -0500, Bryan Christ wrote:
> Please help!
>
> I have generated an xml file using kxmleditor.  With libxml, I am trying
> to use the xpath interface to retrieve a node list for the elements in
> my file.  The document has (currently) a three level hierarchy and I am
> trying to retrieve data from the inner most tier.  My code snippet:
>
> if(!(xmldoc=xmlParseFile("statics.xml"))) break;
> xpath_context=xmlXPathNewContext(xmldoc);
> xpath_object=xmlXPathEvalExpression((xmlChar*)"root/main_ui/config_menu/*",xpath_context);
>
> When I run my code, I get the following error messages:
>
> xmlXPathNodeCollectAndTest xpath.c:1923 : nodelist and node are NULL
> xmlXPathNodeCollectAndTest xpath.c:1923 : nodelist and node are NULL
> xmlXPathNodeCollectAndTest xpath.c:1923 : nodelist and node are NULL
> xmlXPathNodeCollectAndTest xpath.c:1923 : nodelist and node are NULL

  The current node is not defined. Strange but possible, 

> Apparently, each one of these error messages corresponds to each level
> of the hierarchy.  I have tried many permutations of the same
> expression.  In all cases xpath_object is returned invalid.  I suspect
> my syntax for the expression is wrong, but I cannot figure it out.

  Try /root/main_ui/config_menu/* The leading / ask XPath to start
from the root of the document.

> Also, I have studied the code example at
> http://www.xmlsoft.org/tutorial/apd.html and have reviewed the syntax
> for xpath as describe here
> http://www.w3.org/TR/xpath#section-Introduction.  Neither has helped. 
> As far as I can tell, my code is really the same as that provided by the
> example.  Please help!

  Check that example:
    http://xmlsoft.org/examples/index.html#xpath1.c
but it looks really similar. 

Daniel

-- 
Daniel Veillard      | Red Hat Desktop team http://redhat.com/
veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/