Xerces线程安全吗？

Question

taken from here: http://xerces.apache.org/xerces-c/faq-parse-3.html#faq-6

When two or more parser instances exist in a process, the instances can be used concurrently, without external synchronization. That is, in an application containing two parsers and two threads, one parser can be running within the first thread concurrently with the second parser running within the second thread.

But the below code fails whenever the QMutex is commented and does not whenever it is used.

bool reports::validateSchema( QString fileName )
{
    // QMutexLocker lock( &xercesMutex );
    try
    {
        XMLPlatformUtils::Initialize();
    }
    catch(...)
    {
        this->throw_report_exception(__FILE__,__LINE__,__TIME__,__DATE__,"reports::validateSchema",
                                     "unable to initialize Xerces Plateform");
        return false;
    }


    const char* const xsd = "full absloute path to .xsd ==> hard written";

    XercesDOMParser* parser = new XercesDOMParser();

    try
    {
        parser->setValidationSchemaFullChecking(true);
        parser->setDoSchema(true);
        parser->setDoNamespaces(true);
        parser->setValidationConstraintFatal(true);
        parser->setValidationScheme(XercesDOMParser::Val_Auto);

        ParserErrorHandler errHandler;
        parser->setErrorHandler(&errHandler);

        parser->cacheGrammarFromParse(true);
        parser->loadGrammar(xsd,Grammar::SchemaGrammarType,true);


        parser->parse(fileName.toStdString().c_str());
        std::cout << parser->getErrorCount() << std::endl;
        if(parser->getErrorCount()!=0)
        {
            return false;
        }
    }
    catch (const XMLException& toCatch)
    {
        char* message = XMLString::transcode(toCatch.getMessage());
        std::cout << "Exception message is: \n"
                << message << "\n";
        XMLString::release(&message);
        return false;
    }
    catch (const DOMException& toCatch)
    {
        char* message = XMLString::transcode(toCatch.msg);
        std::cout << "Exception message is: \n"
                << message << "\n";
        XMLString::release(&message);
        return false;
    }
    catch (...)
    {
        std::cout << "Unexpected Exception \n" ;
        return false;
    }

    delete parser;
    XMLPlatformUtils::Terminate();


    return true;
}

What am I missing ?

The functions get executed hundreds of times and at some point, I'm getting a segfault from either:

XercesDOMParser* parser = new XercesDOMParser();

or

parser->loadGrammar(xsd,Grammar::SchemaGrammarType,true);

Answer 1

A quote from the same FAQ answer you refer to:

The application also needs to guarantee that the XMLPlatformUtils::Initialize() and XMLPlatformUtils::Terminate() methods are called from the same thread (usually the initial thread executing main()) or proper synchronization is performed by the application if multiple threads call XMLPlatformUtils::Initialize() and XMLPlatformUtils::Terminate() concurrently.