Error using dll in Debug call

[myisjwj]

dll code:

Code: Pascal  [Select][+][-]

1. library DllClass;
2.  
3. {$mode objfpc}{$H+}
4.  
5. uses
6.   Classes
7.   { you can add units after this };
8. type
9. TMyCls = class(TObject)
10.   private
11.     temp:Integer;
12.   public
13.     constructor Create(inInt:Integer);
14.     function Foo(inInt: Integer):Integer;virtual;
15.   end;
16.  
17. function TMyCls.Foo(inInt: Integer):Integer;
18. begin
19.   Result:=inInt*inInt*temp;
20. end;
21. constructor TMyCls.Create(inInt:Integer);
22. begin
23.   temp:=inInt;
24. end;
25.  
26. function CreateMyClass(inInt:Integer): TMyCls; stdcall;
27. begin
28.   Result := TMyCls.Create(inInt);
29. end;
30. exports
31.   CreateMyClass;
32. begin
33. end.

EXE code

Code: Pascal  [Select][+][-]

1.   TMyCls = class(TObject)
2.   private
3.   public
4.     function Foo(inInt: Integer):Integer;virtual;abstract;
5.   end;
6.   function CreateMyClass(inInt:Integer):TMyCls;stdcall; external 'DllClass.dll';
7.  
8. var
9.   outint:Integer;
10.   MyObj: TMyCls;
11. begin
12.   MyObj:=CreateMyClass(2);
13.   outint:= MyObj.Foo(5);
14.   ShowMessage(IntToStr(outint));
15.   MyObj.Free;
16. end;    

outint:= MyObj.Foo(5); Error "Invalid type cast" is displayed in Debug mode. It can run in other modes

[PascalDragon]

You should not use classes across the module boundary, this is not supported and can and will only lead to problems. And also you should not free memory that had been allocated in one module in another module unless you also use a shared memory manager.