imap_fetchheader返回空白

Question

我正在使用imap_fetchheader函数从Gmail帐户获取未见过的电子邮件的标题信息。

我在消息ID的循环中使用它。它为某些内容提供了正确的内容，并且在某些内容之后它返回空白。

    for ($i = 0; $i < $unreadCounterGmail; $i++) {
$headers = imap_fetchheader($mbox, $unread[$i]);
        echo "Loop counter = " . $i . " Message Number = " . $unread[$i] . " Header counter = " . count($headers) . "\n";
        $subject = array();
        $date = array();
        $registrar = array();
        preg_match_all('/^Subject: (.*)/m', $headers, $subject);
        preg_match_all('/^Date: (.*)/m', $headers, $date);
        preg_match_all('/^From: (.*)/m', $headers, $registrar);

        $str = $subject[1][0];
        $rgsmail = $registrar[1][0];
        $receiveDate = $date[1][0];
echo "Reading FROM Gmail Acc :: Subject = " . $str . "  :: From = " . $rgsmail . " :: Date = " . $receiveDate . " \n";
}