I am trying to create a xmlNode from an XML string with xmlParseBalancedChunkMemory but when the XML string containing a prefix/namespace in it, libxml2 would throw error 201 (XML_NS_ERR_UNDEFINED_NAMESPACE). What is the proper way to parse an XML string?

The code I used to parse the XML string:

    xmlNodePtr newNode = nullptr;
    // int rc = xmlParseBalancedChunkMemory(doc, NULL, NULL, 0,
    //                                 BAD_CAST content,
    //                                 &newNode);
    int rc = xmlParseBalancedChunkMemoryRecover(doc, NULL, NULL, 0,
                                     BAD_CAST content,
                                     &newNode, 1);

The XML string I’m trying to parse:

<ds:X509Certificate>MII...blah</ds:X509Certificate>

The error being thrown:

libxml<Err>: namespace 
libxml<Err>: error : 
libxml<Err>: Namespace prefix ds on X509Certificate is not defined
libxml<Err>: <ds:X509Certificate>MII...blah</ds:X509Certificate>
libxml<Err>:   

I don’t understand why it throws that error when the doc being passed already contains the namespace definitions.

<EDSCrate xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

PS: the same code worked fine on normal, non-prefixed, XML strings such as <a>helloworld</a> or helloworld (text node).