php smtp发送邮件的函数

php实现的smtp发送邮件的函数，带smtp验证功能，有详细的注释，适合研究smtp发信的朋友参考。

完整代码如下。

".$lb,"250","MAIL FROM error: ");
      //6、发送Rcpt To。期待返回250
      $smtp[] = array("RCPT TO: ".$lb,"250","RCPT TO error: ");
      //7、发送DATA，期待返回354
      $smtp[] = array("DATA".$lb,"354","DATA error: ");
      //8.0、发送From
      $smtp[] = array("From: ".$deliver.$lb,"","");
      //8.2、发送To
      $smtp[] = array("To: ".$to.$lb,"","");
      //8.1、发送标题
      $smtp[] = array("Subject: ".$subject.$lb,"","");
      //8.3、发送其他Header内容
      foreach($hdr as $h) {$smtp[] = array($h.$lb,"","");}
      //8.4、发送一个空行，结束Header发送
      $smtp[] = array($lb,"","");
      //8.5、发送信件主体
      if($bdy) {foreach($bdy as $b) {$smtp[] = array(base64_encode($b.$lb).$lb,"","");}}
      //9、发送“.”表示信件结束，期待返回250
      $smtp[] = array(".".$lb,"250","DATA(end)error: ");
      //10、发送Quit，退出，期待返回221
      $smtp[] = array("QUIT".$lb,"221","QUIT error: ");

        //打开smtp服务器端口
        $fp = @fsockopen($smtp_host, 25);
        if (!$fp) echo "Error: Cannot conect to ".$smtp_host."
";
        while($result = @fgets($fp, 1024)){if(substr($result,3,1) == " ") { break; }}
       
        $result_str="";
        //发送smtp数组中的命令/数据
        foreach($smtp as $req){
                //发送信息
                @fputs($fp, $req[0]);
                //如果需要接收服务器返回信息，则
                if($req[1]){
                        //接收信息
                        while($result = @fgets($fp, 1024)){
                                if(substr($result,3,1) == " ") { break; }
                        };
                        if (!strstr($req[1],substr($result,0,3))){
                                $result_str.=$req[2].$result."
";
                        }
                }
        }
        //关闭连接
        @fclose($fp);
        return $result_str;
}

//调用示例
#echo send_mail($_POST["email"],$tosubject,$_POST["errortext"]);
echo send_mail('[e-mail]','脚本学堂，欢迎大家的光临','程序员之家_bbs.it-home.org');
echo time();
?>