calling a javascript callback function from C++

using namespace v8;

    int
    main (int argc, char *argv[])
    {
      //handle scope created
      HandleScope handle_scope;
      //creating context
      Persistent < Context > context = Context::New ();
      Context::Scope context_scope (context);
      // need source scrip and result
      Handle < String > source;
      Handle < Script > script;
      Handle < Value > result;

      // Create a string containing the JavaScript source code.
      source = String:: New(" var obj={name:8}; obj.abc=function(){return 9;};   function xyz() { var match = 0;if(arguments[0] == arguments[1]) { match = 1; }     return match; }   ");

      // Compile the source code.
      script = Script::Compile (source);


      // Run the script to get the result.
      result = script->Run ();
      // Dispose the persistent context.
      context.Dispose ();


      // create the global object
      Handle < v8::Object > global = context->Global ();
      Handle < v8::Value > value = global->Get (String::New ("xyz"));
      Handle < v8::Function > func = v8::Handle < v8::Function >::Cast (value);
      Handle < Value > js_result;


      Handle < Value > ret = func->Call (global, 0, 0);


    if (ret.IsEmpty ())
    {
        if(ret->IsNumber())
        {
            std::cout<<" \nis Number\n";
        }
        else
        {
            std::cout<<" \nNot a Number\n";
        }
    }
    else
    std::cout<< " is null\n";
    return 0;

 }