php 发送邮件与pop3邮件登录代码

<?php
function send_msg($to, $subject, $body) {
    $send_addr = &#39;admin@test.com&#39;; //发送人地址
    $header = "from: admin <" . $send_addr . ">rn"; //设置email头
    ini_set(&#39;sendmail_from&#39;, $send_addr);
    mail($to, $subject, $body, $header);
}
?>

<?php
function pop3_login($host, $username, $password) {
    global $debug;
    if (emptyempty($host)) {
        return false;
    }
    if ($debug) echo "open hostname: " . $host . ",port: " . $port . "n";
    $conn = @fsockopen($host, 110, $err_no, $err_str, 5);
    if (!$conn) {
        return false;
    }
    $ret_info = fgets($conn, 1024);
    if (substr($ret_info, 0, 3) == "+ok") {
        if (login($conn, $username, $password)) {
            return true;
        }
    }
    return false;
}
?>

function smtp_login($host, $username, $password) {
    global $debug;
    if (emptyempty($host)) {
        return false;
    }
    if ($debug) echo "open hostname: " . $host . ",port: " . $port . "n";
    $conn = @fsockopen($host, 25, $err_no, $err_str, 5);
    if (!$conn) {
        return false;
    }
    $ret_info = fgets($conn, 1024);
    if (substr($ret_info, 0, 3) == "220") {
        fputs($conn, "helo localhostrn");
        if (substr(fgets($conn, 1024) , 0, 3) == "250") {
            if (login($conn, $username, $password, 25)) {
                return true;
            }
        }
    }
    return false;
}

function imap_login($host, $username, $password) {
    global $debug;
    if (emptyempty($host)) {
        return false;
    }
    if ($debug) echo "open hostname: " . $host . ",port: " . $port . "n";
    $conn = @fsockopen($host, 143, $err_no, $err_str, 5);
    if (!$conn) {
        return false;
    }
    $ret_info = fgets($conn, 1024);
    if (strpos($ret_info, "ok")) {
        fputs($conn, "a001 login $username $passwordrn");
        $ret = fgets($conn, 1024);
        if (strpos($ret, "login ok")) {
            return true;
        }
    }
    return false;
}