奇怪问题，高分(300分)

procedure TForm1.FormCreate(Sender: TObject);
var
  __wsadt: TWSAData;
begin
   WSAStartup(MAKEWORD(2, 2), __wsadt);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
   WSACleanUp;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  s, s1, n, l, v: Integer;
  saddr: TSockAddrIn;
  ov: _OVERLAPPED;
  buf: string;
begin
  s := WSASocket(AF_INET, SOCK_STREAM, 0, nil, 0, 1);
  saddr.sin_family := AF_INET;
  saddr.sin_port := htons(10240);
  saddr.sin_addr.S_addr := htonl(INADDR_ANY);
  l := sizeof(saddr);
  bind(s, @saddr, l);
  listen(s, 5);
  while true do
  begin
    s1 := wsaaccept(s, nil, nil, nil, 0);
    setlength(buf, 1024);
    fillchar(ov, sizeof(ov), #0);
    if wsarecv(s1, pwsabuf(integer(buf)-4), 1, cardinal(l), cardinal(n), Pwsaoverlapped(@ov), nil) = SOCKET_ERROR then
    begin
      v := wsagetlasterror;
      showmessage(inttostr(v));
    end
    else showmessage(copy(buf, 1, l));
  end;
end;