function addAttachment($file,
        $c_type      = 'application/octet-stream',
        $name        = '',
        $isfile      = true,
        $encoding    = 'base64',
        $disposition = 'attachment',
        $charset     = '',
        $language    = '',
        $location    = '',
        $n_encoding  = null,
        $f_encoding  = null,
        $description = '',
        $h_charset   = null,
        $add_headers = array()
    ) {
        $bodyfile = null;

        if ($isfile) {
            // Don't load file into memory
            if ($this->_build_params['delay_file_io']) {
                $filedata = null;
                $bodyfile = $file;
            } else {
                if ($this->_isError($filedata = $this->_file2str($file))) {
                    return $filedata;
                }
            }
            // Force the name the user supplied, otherwise use $file
            $filename = ($name ? $name : $this->_basename($file));
        } else {
            $filedata = $file;
            $filename = $name;
        }

        if (!strlen($filename)) {
            $msg = "The supplied filename for the attachment can't be empty";
            return $this->_raiseError($msg);
        }

        $this->_parts[] = array(
            'body'        => $filedata,
            'body_file'   => $bodyfile,
            'name'        => $filename,
            'c_type'      => $c_type,
            'charset'     => $charset,
            'encoding'    => $encoding,
            'language'    => $language,
            'location'    => $location,
            'disposition' => $disposition,
            'description' => $description,
            'add_headers' => $add_headers,
            'name_encoding'     => $n_encoding,
            'filename_encoding' => $f_encoding,
            'headers_charset'   => $h_charset,
        );

        return true;
    }