Primary Link

How can I get the Primary link title when my menu are getting build.

I tried something like $link['title'] but all I get is a <..

function dune_primary_links($e) {
  $links = menu_primary_links();
  $i = 1;
  
  if ($links) {
    
    foreach ($links as $link) {

      $link = str_replace('<a ', '<a onclick="<?php print dune_primary_links() ?><?php } ?>" ', $link);

    }

   return $output;
}

cheers