pear邮件功能密件抄送不会发送

我从网站复制了 PEAR 邮件的代码，并输入了我的数据。有用。它发送邮件，但是，我想使用密件抄送发送给很多人并保持他们的地址匿名，并且它将发送到 $to 收件人，但不是 $bcc。

代码：

<?php
$message = "yay email!";
require_once("Mail.php");
$from = '[email protected] /cdn-cgi/l/email-protection ';
$to = "[email protected] /cdn-cgi/l/email-protection";
$bcc = "[email protected] /cdn-cgi/l/email-protection";
$subject = " test";
$body = $message;
$host = "smtp.mysite.com";
$username = "myusername";
$password = "mypassword";
$headers = array ('From' => $from,
    'To' => $to,
    'Cc' => $cc,
    'Bcc' => $bcc,
    'Subject' => $subject
);
$recipients = $to;


$smtp = Mail::factory('smtp',
    array ('host' => $host,
        'auth' => true,
        'username' => $username,
        'password' => $password,
        'port' => '25'
    )
);
$mail = $smtp->send($recipients, $headers, $body);
if (PEAR::isError($mail)) {
    echo($mail->getMessage());
}
else {
    echo("Message successfully sent!");
}
?>

附注我在另一个论坛上读到我不应该将标题放入数组中？我无法理解标题的概念。他们做什么以及我应该如何组织他们？我只想要收件人、发件人、主题和密件抄送。

Thanks!

要详细说明 Chaky31 的答案，请发送Bcc使用以下内容，请注意，我们不在标头中指定任何密件抄送信息：

//All other variables should be self explanatory!

//The main recipient
$to = "[email protected] /cdn-cgi/l/email-protection";

//Bcc recipients
$bcc = "[email protected] /cdn-cgi/l/email-protection";

$headers = array ('From' => $from,
  'To' => $to,
  'Subject' => $subject);
$smtp = Mail::factory('smtp',
  array ('host' => $host,
    'port' => $port,
    'auth' => true,
    'username' => $username,
    'password' => $password));

//We append the bcc addresses as comma seperated values to the send method
$mail = $smtp->send($to . "," . $bcc, $headers, $body);