Thread: checking administrator user

Code:

function IsAdmin:Boolean;
const
  SECURITY_NT_AUTHORITY: TSIDIdentifierAuthority = (Value: (0,0,0,0,0,5));
  SECURITY_BUILTIN_DOMAIN_RID = $00000020;
  DOMAIN_ALIAS_RID_ADMINS     = $00000220;
var
  IsUserAnAdmin: function(): BOOL; stdcall;
  hAccessToken: THandle;
  ptgGroups: PTokenGroups;
  dwInfoBufferSize: DWORD;
  psidAdministrators: PSID;
  xi: Integer;
  bSuccess: BOOL;
  hMod: Thandle;
begin
 Result:=True;
 if IsWin9x then Exit;
 Result:=False;
 hAccessToken:=0;
 hMod:=GetModuleHandle('shell32.dll');
 if hMod=0 then hMod:=LoadLibrary('shell32.dll');
 IsUserAnAdmin:=GetProcAddress(hMod,'IsUserAnAdmin');
 if not Assigned(IsUserAnAdmin) then begin
  bSuccess:=OpenThreadToken(GetCurrentThread,TOKEN_QUERY,True,hAccessToken);
  if not bSuccess then if GetLastError=ERROR_NO_TOKEN then
   bSuccess:=OpenProcessToken(GetCurrentProcess,TOKEN_QUERY,hAccessToken);
  if bSuccess then begin
    GetMem(ptgGroups,1024);
    bSuccess:=GetTokenInformation(hAccessToken,TokenGroups,ptgGroups,1024,dwInfoBufferSize);
    CloseHandle(hAccessToken);
    if bSuccess then begin
      AllocateAndInitializeSid(SECURITY_NT_AUTHORITY,2,SECURITY_BUILTIN_DOMAIN_RID,DOMAIN_ALIAS_RID_ADMINS,0,0,0,0,0,0,psidAdministrators);
      if ptgGroups.GroupCount>0 then
        for xi:=0 to ptgGroups.GroupCount-1 do
         if EqualSid(psidAdministrators,ptgGroups.Groups[xi].Sid) then begin
          Result:=True;
          Break;
         end;
      FreeSid(psidAdministrators);
    end;
    FreeMem(ptgGroups);
  end;
 end
 else Result:=IsUserAnAdmin();
end;

Example of use in formCreate...FormShow or timer

Code:

      if IsAdmin then {ADM} else
Label.Caption := 'Execute como Administrador';