socket php

$socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP);
socket_bind($socket,'0.0.0.0',6666);

while(true){
    socket_listen($socket);
    $sock = socket_accept($socket);
    $res = socket_read($sock,2048);
    echo $res.PHP_EOL;
    socket_write($sock,'收到客户端消息: '.$res);
}

$socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP);
socket_connect($socket,'0.0.0.0',6666);
$msg = 'hlllo server';
socket_write($socket,$msg);
$res = socket_read($socket,2048);
echo $res;