function vc_flagcdn_url(?string $cc, int $w = 20): string
{
    $cc = strtolower(trim((string)$cc));
    if ($cc === '' || !preg_match('~^[a-z]{2}$~', $cc)) return '';

    // FlagCDN supports discrete widths. Use nearest safe bucket.
    // Common valid sizes: 20, 40, 80, 160 (and more).
    $w = (int)$w;
    if ($w <= 20) $w = 20;
    elseif ($w <= 40) $w = 40;
    elseif ($w <= 80) $w = 80;
    else $w = 160;

    return 'https://flagcdn.com/w' . $w . '/' . $cc . '.png';
}

function vc_flag_img(?string $cc, int $w = 20, string $class = 'vcFlag', string $extraStyle = ''): string
{
    $url = vc_flagcdn_url($cc, $w);
    if ($url === '') return '';

    $name = vc_country_name($cc);

    $style = $extraStyle !== '' ? ' style="' . h($extraStyle) . '"' : '';
    return '<img class="' . h($class) . '" src="' . h($url) . '" width="18" height="14" alt="' . h($name) . '" title="' . h($name) . '" loading="lazy" referrerpolicy="no-referrer"' . $style . '>';
}
<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function vc_is_valid_username() in /home/voicechatline/htdocs/voicechatline.com/profile.php:11
Stack trace:
#0 {main}
  thrown in <b>/home/voicechatline/htdocs/voicechatline.com/profile.php</b> on line <b>11</b><br />