Whitelist get custom field in a array

I’m trying to install a whitelist register in my site. So i’ve found this code :

function buddypress_inscrit_selon_domaine( $result ) {
 $domainesOK = array(
 'gmail.com', 
 'infopower.fr'
 );
 $error = 'Vous devez utiliser un domaine valide.';
 $email = $result['user_email']; 
 $domaine = array_pop(explode('@', $email));
if ( ! in_array($domaine, $domainesOK))
 {
 $result['errors']->add('user_email', __($error, 'bp-restrict-email-domains' ) );
 };
 return $result;
}
add_filter( 'bp_core_validate_user_signup', 'buddypress_inscrit_selon_domaine' );

It works very well. But i’d like to use a custom post and custom field to get back the whitelist domain. Well, i want that the user can add a new domain in a custom field in a post. Well, for each domain a post. My problem is how to get back this custom field of all this post type in a array, and put the array on the place of this :

$domainesOK = array( 'gmail.com',  'infopower.fr' );

I’ve tried with this :

$domainesOK = $wpdb->get_col("SELECT meta_value FROM $wpdb->postmeta WHERE meta_key = 'urldudomaine'" );

But the program doesn’t filter the whitelist.

Well, thanks a lot for any help. And sorry for my bad english ;-)

Françoise

via Chebli Mohamed