使用PHP无法在函数内获取值

I have one issue.I am trying to print the file data into one called function its not printing anything using PHP. I am explaining my code below.

$action=$_REQUEST['action'];
if($action=='addSellRent'){
   if(array_key_exists('file1',$_FILES)){
        $result[]=uploadSellImage($_FILES);
  }
}
function uploadSellImage($_FILES){
    print_r($_FILES);exit;
}

Here inside trying to print the file but its showing blank. Here I need to pass the file data to the uploadSellImage function and try to doing some operation there. Please help me.

try this

function uploadSellImage($upload){
    echo "<pre>"; print_r($upload);die;
}