php_stream_select_example.php

<?php
$arr = array(
    'www.baidu.com',
    'tieba.baidu.com',
    'www.163.com',
    'www.sina.com.cn',
);
$reads = array();
foreach ($arr as $k=>$r) {
    $writes[] = stream_socket_client("tcp://$r:80",$errno, $errstr, 0.5);
}
$reads = NULL;
$except = NULL;
while ($writes && stream_select($reads, $writes, $except, 0.5) !== false) {
    foreach ($writes as $k=>$fp) {
        stream_set_timeout($fp, 2);
        fwrite($fp, "GET / HTTP/1.0\r\n\r\n");
        $res = fread($fp, 2000);
        $info = stream_get_meta_data($fp);
        unset($writes[$k]);
        fclose($fp);
        var_dump($res);
        var_dump($info);
        var_dump($fp);
    }
}