TCP服务器工作正常，但udp服务器在php中显示错误

下面是php代码

    <?php
$hostname = "127.0.0.1";
$portno = "5060";
$sock = socket_create(AF_INET, SOCK_STREAM, 0) or die("Socket create error'n");
socket_bind($sock, $hostname, $portno) or die("Socket bind error'n");
socket_listen($sock, 3) or die("Could not set up socket listener'n");
while(1)
{
    echo "socket connection started'n";
    $accept = socket_accept($sock) or die("Could not accept incoming connection'n");
    while($recv = socket_read($accept, 24000))
    {
        $sent = socket_write($sock, $recv, strlen($recv));
        echo $recv;
    }
    socket_close($accept);
    echo "socket connection done'n";
}
socket_close($sock);
?>

作为TCP服务器。为了将其转换为udp服务器，我修改了创建服务器

$sock = socket_create(AF_INET, SOCK_DGRAM, 0) or die("Socket create error'n");

但是显示错误

Could not set up socket listener