得到本地计算机名

function GetComputerName: AnsiString;
var
  lpBuffer: array [0 .. MAX_PATH] of char;
  dwSize: DWORD;
begin
  dwSize := MAX_PATH;
  if not Windows.GetComputerName(lpBuffer, dwSize) then
    raise Exception.Create(SysErrorMessage(GetLastError()));
  Result := StrPas(lpBuffer);
end;

得到系统登录名

procedure TForm1.btn4Click(Sender: TObject);
var
  Username: pChar;
  nSize: Cardinal;
begin
  Username := StrAlloc(30);
  nSize := 30;
  GetUserName(Username, nSize);
  ShowMessage(Username);
  StrDispose(Username);
end;

得到系统的IP地址

function ComputerLocalIp: string;
var
  ch: array [1 .. 32] of char;
  wsData: TWSAData;
  myHost: phostEnt;
  i: Integer;
begin
  Result := '';
  if wsastartup(2, wsData) <> 0 then // can't start winsock
    exit;
  try
    if gethostname(@ch[1], 32) <> 0 then
      exit; // gethost fiald;
  except
    exit;
  end;
  myHost := gethostbyname(@ch[1]); //
  if myHost = nil then
    exit;
  for i := 1 to 4 do
  begin
    Result := Result + IntToStr(Ord(myHost.h_addr^[i - 1]));
    if i < 4 then
      Result := Result + '.';
  end;
end;