function GDAL: LongWord;
type
  TDVCLAL = array[0..3] of LongWord;
  PDVCLAL = ^TDVCLAL;
var
  P: Pointer;
  A1, A2: LongWord;
  PAL1s, PAL2s: PDVCLAL;
  ALOK: Boolean;
begin
  P := ALR;//从资源文件获得
  if P <> nil then
  begin
    A1 := AL1(P^);
    A2 := AL2(P^);
    Result := A1;
    PAL1s := @AL1s;
    PAL2s := @AL2s;
    ALOK := ((A1 = PAL1s[0]) and (A2 = PAL2s[0])) or
            ((A1 = PAL1s[1]) and (A2 = PAL2s[1])) or
            ((A1 = PAL1s[2]) and (A2 = PAL2s[2]));
    FreeResource(Integer(P));
    if not ALOK then ALV;//抛出异常,说Application is not licensed to use this feature
  end
  else Result := AL1s[3];
end;

const
  AL1s: array[0..3] of LongWord = ($FFFFFFF0, $FFFFEBF0, 0, $FFFFFFFF);
  AL2s: array[0..3] of LongWord = ($42C3ECEF, $20F7AEB6, $D1C2F74E, $3F6574DE);

procedure ALV;
begin
  raise Exception.CreateRes(@SNL);
end;

function ALR: Pointer;
var
  LibModule: PLibModule;
begin
  if MainInstance <> 0 then
    Result := Pointer(LoadResource(MainInstance, FindResource(MainInstance, 'DVCLAL',
      RT_RCDATA)))
  else
  begin
    Result := nil;
    LibModule := LibModuleList;//这里是一个链表,其实想学习链表的朋友可以来看看
    while LibModule <> nil do//遍历链表
    begin
      with LibModule^ do
      begin
        Result := Pointer(LoadResource(Instance, FindResource(Instance, 'DVCLAL',
          RT_RCDATA)));
        if Result <> nil then Break;
      end;
      LibModule := LibModule.Next;
    end;
  end;
end;

procedure RCS;
var
  P: Pointer;
  ALOK: Boolean;
begin
  P := ALR;
  if P <> nil then
  begin
    ALOK := (AL1(P^) = AL1s[2]) and (AL2(P^) = AL2s[2]);
    FreeResource(Integer(P));
  end
  else
    ALOK := False;
  if not ALOK then
    ALV;
end;

procedure RPR;
var
  AL: LongWord;
begin
  AL := GDAL;
  if (AL <> AL1s[1]) and (AL <> AL1s[2]) then
    ALV;
end;