[Libreoffice] how to acquire an ScDocument reference "from scratch"

Hello List,

I'm trying to get hold of an ScDocument "from scratch".  I have naively 
attempted to replicate another section of code, but for the life of me 
can't figure out what I'm missing.  My code crashes with a SIGSEGV on 
this line:

aDocShell = new ScDocShell();

I think I've boiled it down to a null pointer dereference (see attached, 
please), but that implies the existing code is incorrect, which I'm not 
yet ready to admit.

Any pointers very welcome.

Thanks,

Kevin

// ----- My code ...

[...]
#include "docsh.hxx"
[...]

SomeClass::SomeClass ( ) {
        printf("Step 1: Construction ... ");
        fflush( stdout );

        // This call dies, but I don't understand why.  I've traced it to
        // 'getComponentContext' returning a NULL pointer, and below.
        m_pDocSh = new ScDocShell();

        printf("done.\n");  // <-- this line never reached, as a SIGSEGV occurs
}


//
// In case it's pertinent, here's is the call stack at time of SIGSEGV:
//

// SvtViewOptionsBase_Impl::SvtViewOptionsBase_Impl(rtl::OUString const&) (viewoptions.cxx:367)
// SvtViewOptions::AcquireOptions() (viewoptions.cxx:1246)
// SfxApplication::SfxApplication() (app.cxx:314)
// SfxApplication::GetOrCreate() (app.cxx:278)
// SfxGetpApp() (app.hxx:288)
// SfxObjectShell_Impl::SfxObjectShell_Impl(SfxObjectShell&) (objxtor.cxx:287)
// SfxObjectShell::SfxObjectShell(unsigned long) (objxtor.cxx:302)
// ScDocShell::ScDocShell(unsigned long)
// ... a few more irrelevant stack pieces

//
// ----- Tracings through LO code
//   (I start tracing below within unotools/source/config/viewoptions.cxx )
//

// comphelper/source/processfactory/processfactory.cxx:getComponentContext
{
        Reference< XComponentContext > xRet;
        // [...]
        return xRet;  // at this point, xRet is NULL
}

//
// Which then makes this pass a NULL to theDefaultProvider::get
//
css::uno::Reference< css::uno::XInterface > ConfigurationHelper::openConfig(
  const css::uno::Reference< css::lang::XMultiServiceFactory > xSMGR,
  const ::rtl::OUString& sPackage,
  sal_Int32 eMode
) {
        css::uno::Reference< css::lang::XMultiServiceFactory > xConfigProvider(
          css::configuration::theDefaultProvider::get(
            getComponentContext( xSMGR )
          )
        );
        // [...]
}

//
// theDefaultProvider::Get then tries to use the NULL pointer:
//
class theDefaultProvider {
public:
        static ::com::sun::star::uno::Reference< ::com::sun::star::lang::XMultiServiceFactory > get(
          ::com::sun::star::uno::Reference< ::com::sun::star::uno::XComponentContext > const & 
context
        ) {
                ::com::sun::star::uno::Reference< ::com::sun::star::lang::XMultiServiceFactory > 
instance;

                // This line is what appears to fail, as 'context' is currently a
                // NULL pointer
                if ( ! ( context->getValueByName( 
::rtl::OUString(RTL_CONSTASCII_USTRINGPARAM("/singletons/com.sun.star.configuration.theDefaultProvider")))
> > = instance) || !instance.is() )
                        throw 
::com::sun::star::uno::DeploymentException(::rtl::OUString(RTL_CONSTASCII_USTRINGPARAM("component 
context fails to supply singleton com.sun.star.configuration.theDefaultProvider of type 
com.sun.star.lang.XMultiServiceFactory")), context);

                return instance;
        }

// [...]
}