PHP uses pear_smtp to send emails, pear_smtp sends emails_PHP tutorial

<&#63;php 
 require_once "vendor/autoload.php"; 
  
 $from = "test<test@163.com>"; 
 $to = "test <test@outlook.com>"; 
 $subject = "Hi!"; 
 $body = "Hi,\n\nHow are you&#63;"; 
  
 $host = "smtp.163.com"; 
$port = "25"; 
 $username = "test@163.com"; 
 $password = "test123"; 
  
 $headers = array ('From' => $from, 
  'To' => $to, 
  'Subject' => $subject); 
 $smtp = Mail::factory('smtp', 
  array ('host' => $host, 
   'port' => $port, 
   'auth' => true, 
  // 'debug'=>true, 
   'username' => $username, 
   'password' => $password)); 
  
 $mail = $smtp->send($to, $headers, $body); 
  
 if (PEAR::isError($mail)) { 
  echo("<p>" . $mail->getMessage() . "</p>"); 
 } else { 
  echo("<p>Message successfully sent!</p>"); 
 } 
 &#63;>

 $subject = "This mail is sent from SMTP.";
$mail_body = "This is the body of the mail which is sent using SMTP.";
$from = "From: From Name <fromaddress@xpertdeveloper.com>"; 
$to = "To: To Name <toaddress@xpertdeveloper.com>"; 
$receiver = "toaddress@xpertdeveloper.com"; 
 
// Setting up the headers
$headers["From"] = $from; 
$headers["To"] = $to; 
$headers["Subject"] = $subject; 
$headers["Reply-To"] = "reply@address.com"; 
$headers["Content-Type"] = "text/plain; charset=ISO-2022-JP"; 
$headers["Return-path"] = "returnpath@address.com"; 
 
// Setting up the SMTP setting
$smtp_info["host"] = "smtp.server.com"; 
$smtp_info["port"] = "25"; 
$smtp_info["auth"] = true; 
$smtp_info["username"] = "smtp_user"; 
$smtp_info["password"] = "smtp_password"; 
 
// Creating the PEAR mail object :
$mail_obj =& Mail::factory("smtp", $smtp_info); 
 
// Sending the mail now
$mail_sent = $mail_obj->send($receiver, $headers, $mail_body); 
 
// If any error the see for that here:
if (PEAR::isError($mail_sent)) { print($mail_sent->getMessage());}

; UNIX: "/path1:/path2" 
include_path = ".:./php/pear"
;
; Windows: "\path1;\path2"
;include_path = ".;c:\php\pear"
require 'Net/SMTP.php';
$host = '126.com';//smtp服务器的ip或域名
$username= 'arcow';//登陆smtp服务器的用户名
$password= 'secret';//登陆smtp服务器的密码
$from = 'arcow@126.com';  //谁发的邮件
$rcpt = array('test@test.com', 'arcow@126.com');//可设多个接收者
$subj = "Subject: 你是谁\n";//主题
$body = "test it";//邮件内容
/* 建立一个类 */
if (! ($smtp = new Net_SMTP($host))) {
  die("无法初始化类Net_SMTP!\n");
}
/* 开始连接SMTP服务器*/
if (PEAR::isError($e = $smtp->connect())) {
  die($e->getMessage() . "\n");
}
/* smtp需要身份验证 */
$smtp->auth($username,$password,"PLAIN");
/*设置发送者邮箱 */
if (PEAR::isError($smtp->mailFrom($from))) {
  die("无法设置发送者邮箱为 <$from>\n");
}
/* 设置接收邮件者 */
foreach ($rcpt as $to) {
  if (PEAR::isError($res = $smtp->rcptTo($to))) {
    die("邮件无法投递到 <$to>: " . $res->getMessage() . "\n");
  }
}
/* 开始发送邮件内容 */
if (PEAR::isError($smtp->data($subj . "\r\n" . $body))) {
  die("Unable to send data\n");
}
/* 断开连接 */
$smtp->disconnect();
echo "发送成功！";
&#63;>