Zephir\Variable::isDoublePointer PHP Method

    public function isDoublePointer()
    {
        return $this->doublePointer;
    }

 public function ifVariableValueUndefined(Variable $var, CompilationContext $context, $useBody = false, $useCodePrinter = true)
 {
     if ($var->isDoublePointer()) {
         return parent::ifVariableValueUndefined($var, $context, $useBody, $useCodePrinter);
     }
     $body = 'Z_TYPE_P(' . $this->getVariableCode($var) . ') == IS_UNDEF';
     $output = 'if (' . $body . ') {';
     if ($useCodePrinter) {
         $context->codePrinter->output($output);
     }
     return $useBody ? $body : $output;
 }