FIX: IXMLDOMNode::selectSingleNode Returns Invalid Pointer (269511)

The information in this article applies to:

Microsoft XML 2.0
Microsoft Visual C++, 32-bit Enterprise Edition 6.0
Microsoft Visual C++, 32-bit Professional Edition 6.0
Microsoft Visual C++, 32-bit Learning Edition 6.0

This article was previously published under Q269511

SYMPTOMS

The IXMLDOMNode::selectSingleNode method returns the first node selected by a given XPath query. selectSingleNode should return NULL if no node is found. However, in the 2.0 version of the XML parser, an uninitialized pointer may be returned. This is only a problem with XML applications written in Visual C++ that use the #import directive.

RESOLUTION

This problem has been fixed in Microsoft XML (MSXML) version 2.5 or later. MSXML 2.5 is shipped with Microsoft Windows 2000 or Microsoft Internet Explorer 5.01 SP1 and Microsoft Internet Explorer 5.5.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

This problem was corrected in MSXML 2.5.

MORE INFORMATION

When you import the MSXML type library in Visual C++, the wrapper implementation created for selectSingleNode looks like this (in the Msxml.tli file):

inline IXMLDOMNodePtr IXMLDOMNode::selectSingleNode ( _bstr_t queryString )
{
    struct IXMLDOMNode * _result;
    HRESULT _hr = raw_selectSingleNode(queryString, &_result);
    if (FAILED(_hr)) _com_issue_errorex(_hr, this, __uuidof(this));
    return IXMLDOMNodePtr(_result, false);

}

If the query does not find the node then raw_selectSingleNode returns S_FALSE. The variable _result is not properly assigned to NULL, so the smart pointer that is returned to the node is invalid.

REFERENCES

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

269238 INFO: Version List of the Microsoft XML Parser

Modification Type:	Major	Last Reviewed:	12/5/2003
Keywords:	kbBug kbfix kbMSXML250fix kbMSXMLnosweep KB269511 kbAudDeveloper