Get host name using IP-address

Use IPAddrToName function. This function get host information by using GetHostByAddr function.

function IPAddrToName(IPAddr: string): string;
var
  SockAddrIn: TSockAddrIn;
  HostEnt: PHostEnt;
  WSAData: TWSAData;
begin
  WSAStartup($101, WSAData);
  SockAddrIn.sin_addr.s_addr:=inet_addr(PChar(IPAddr));
  HostEnt:= GetHostByAddr(@SockAddrIn.sin_addr.S_addr, 4, AF_INET);
  if HostEnt<>nil then
  begin
    Rresult:=StrPas(Hostent^.h_name)
  end
  else
  begin
    Result:='';
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Label1.Caption:=IPAddrToName(Edit1.Text);
end;