问socket_bind()：无法绑定地址

EN

$host = "127.0.0.1";
$port = 80;

//no timeout
set_time_limit(0);

//create socket
$socket=socket_create(AF_INET, SOCK_STREAM, 0) or die("Could not create socket\n");


if (!socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1)) {
    echo socket_strerror(socket_last_error($socket));
    exit;
}

$result = socket_bind($socket, $host, $port) or die("Could not bind socket\n");