attachment_cid() public method

Useful for attached inline pictures
public attachment_cid ( string $filename ) : string
$filename string
return string
 public function attachment_cid($filename)
 {
     if ($this->mailer_engine == 'phpmailer') {
         for ($i = 0, $c = count($this->_attachments); $i < $c; $i++) {
             if ($this->_attachments[$i]['name'][0] === $filename) {
                 $this->_attachments[$i]['cid'] = uniqid(basename($this->_attachments[$i]['name'][0]) . '@');
                 return $this->_attachments[$i]['cid'];
             }
         }
     } elseif ($this->_is_ci_3) {
         return parent::attachment_cid($filename);
     }
     return FALSE;
 }