PHP sets email as seen in imapserver

For example, I want to read unread emails from imapserver (gmail) and set the email to read after obtaining the content. However, imap_setflag_full does not seem to work. The content can be read now, but cannot be set to seen. The Code is as follows {code ...} parameter... for example, I want to read unread emails from imap server (gmail) and set the email to read after obtaining the content. However, imap_setflag_full does not seem to work. The content can be read now, but cannot be set to seen. The Code is as follows:

$mbox = imap_open("{imap.gmail.com/imap/ssl/novalidate-cert}INBOX", "XXX@gmail.com", "XXX");try{    if($mbox){        //trouver les numéros de mails non-lus        $mails_unseen = imap_search($mbox, 'UNSEEN');        //print_r($mailunseen);        if (!empty($mails_unseen)){            //pour chaque mail non-lu            foreach($mails_unseen as $mail){                //pour les mail unipart                echo "hehe";                imap_setflag_full($mbox, $mail, "\\Seen \\Flagged", ST_UID);   //mettre état de mail à déjà-lu            }        }else{            throw new Exception("Pas de mail recent");        }        imap_close($mbox);    }else{        throw new Exception("Appel echoue");    }}catch(Exception $e){    echo 'Message: '.$e->getMessage().PHP_EOL; }

An answer http://stackoverflow.com/questions/6765736/set-an-mail-as-seen-on-imap-server on stakoverflow has been referenced

But it still doesn't work...

Reply content:

For example, I want to read unread emails from imap server (gmail) and set the email to read after obtaining the content. However, imap_setflag_full does not seem to work. The content can be read now, but cannot be set to seen. The Code is as follows:

$mbox = imap_open("{imap.gmail.com/imap/ssl/novalidate-cert}INBOX", "XXX@gmail.com", "XXX");try{    if($mbox){        //trouver les numéros de mails non-lus        $mails_unseen = imap_search($mbox, 'UNSEEN');        //print_r($mailunseen);        if (!empty($mails_unseen)){            //pour chaque mail non-lu            foreach($mails_unseen as $mail){                //pour les mail unipart                echo "hehe";                imap_setflag_full($mbox, $mail, "\\Seen \\Flagged", ST_UID);   //mettre état de mail à déjà-lu            }        }else{            throw new Exception("Pas de mail recent");        }        imap_close($mbox);    }else{        throw new Exception("Appel echoue");    }}catch(Exception $e){    echo 'Message: '.$e->getMessage().PHP_EOL; }

An answer http://stackoverflow.com/questions/6765736/set-an-mail-as-seen-on-imap-server on stakoverflow has been referenced

But it still doesn't work...