how to pass parameter in wordpress plugin

I am trying to pass argument in function and print the output in wordpress plugin i was not able to pass parameter here's my code

global $postidd;
$postidd=$_REQUEST["postid"];
function getcontent($postidd)
{
   // do something with the args


if($postidd)
{

      $args12 = array(
                    'p'=>15,
                    'post_type' => 'offers',
                    'orderby' => 'title',
                    'order' => 'ASC'
                );
      $the_query12 = new WP_Query( $args12 );           
      if ( $the_query12->have_posts() ) : while ( $the_query12->have_posts() ) : $the_query12->the_post(); 

     return   $postidd;

      endwhile;endif;     

         return   $postidd;

}
}

via Chebli Mohamed