OLE and Widestring

[dseligo]

I have a question regarding OLE and Widestring type.

I am creating OLE object, then calling some method with parameters, something like that:

Code: Pascal  [Select][+][-]

1. var ole: OleVariant;
2.     sParameter:String;
3. ...
4. sParameter:='test_string';
5. ole := CreateOLEObject('...ole object...');
6. ole.SomeFunction(sParameter);
7.  

And this doesn't work well.

If instead of variable I use literal string then it works fine:

Code: Pascal  [Select][+][-]

1. ole.SomeFunction('test_string');

I made it working by declaring widestring variable and use it like this:

Code: Pascal  [Select][+][-]

1. wsParameter:Widestring;
2. ...
3. wsParameter:=sParameter;
4. ...
5. ole.Somefunction(wsParameter);
6.  

My question is: Is there a simpler way to use "String" type variable to call OLE method? I tried casting, without luck:

Code: Pascal  [Select][+][-]

1. ole.Somefunction(WideString(sParameter));

And here (https://wiki.freepascal.org/Widestring) it says that correct way is to use UTF8ToUTF16 function from LazUTF8, I tried like that and it doesn't work either (I get SIGSEGV exception):

Code: Pascal  [Select][+][-]

1. ole.Somefunction(UTF8ToUTF16(sParameter));

I have this string variable declared elsewhere, and I use it in multiple places in program so I don't want to declare it as a Widestring in a first place - I need to convert it before calling OLE method.

[PascalDragon]

Turns out that most of the problems you have (likely) seen where due to a buggy implementation of the parameter dispatching. I have now fixed this in trunk (revisions 47516-47519). If you'd please check whether it works correctly there it would be great and I'd merge that back to 3.2.1 then (so that it will be in the upcoming 3.2.2).

As a workaround (in 3.2.0 and older) you should indeed best use WideString variables.

[dseligo]

Thanks for help. It is somewhat better but it isn't solved yet.

I enabled DEBUG_COMDISPATCH in ComObj.pas. This is test program I used:

Code: Pascal  [Select][+][-]

1. program proba;
2. uses ComObj, Variants;
3.  
4. { $define ws}
5.  
6. var ole: OleVariant;
7.     sPar1,sPar2,sPar3,sPar4,sPar5,sPar6,sPar7:{$ifdef ws}WideString{$else}String{$endif};
8.  
9. begin
10.   sPar1:='FISKAL 4';
11.   sPar2:='98765432109';
12.   sPar3:='19.11.2020 09:09:32';
13.   sPar4:='100';
14.   sPar5:='P1';
15.   sPar6:='333';
16.   sPar7:='99.99';
17.  
18.   ole := CreateOLEObject('Raverus.FiskalizacijaDEV.COM.CentralniInformacijskiSustav');
19.   WriteLn(ole.ZastitniKodIzracun(sPar1,sPar2,sPar3,sPar4,sPar5,sPar6,sPar7));
20.   VarClear(ole);
21. end.

This is the output when parameters are WideString:

Code: Pascal  [Select][+][-]

1. ComObjDispatchInvoke called
2. ComObjDispatchInvoke: @CallDesc = $0044004C CallDesc^.ArgCount = 7
3. SearchIDs: Searching 1 IDs
4. SearchIDs: Original name: ZastitniKodIzracun Len: 18
5. SearchIDs: Translated name: ZastitniKodIzracun
6. SearchIDs: GetIDsOfNames result = 00000000
7. SearchIDs: ID[0] = 1610743821
8. DispatchInvoke: Got 7 arguments   NamedArgs = 0
9. DispatchInvoke: Params = 0145FF1C
10. DispatchInvoke: Got ref argument with type = 8 Value = 99.99
11. DispatchInvoke: Params = 0145FF20
12. DispatchInvoke: Got ref argument with type = 8 Value = 333
13. DispatchInvoke: Params = 0145FF24
14. DispatchInvoke: Got ref argument with type = 8 Value = P1
15. DispatchInvoke: Params = 0145FF28
16. DispatchInvoke: Got ref argument with type = 8 Value = 100
17. DispatchInvoke: Params = 0145FF2C
18. DispatchInvoke: Got ref argument with type = 8 Value = 19.11.2020 09:09:32
19. DispatchInvoke: Params = 0145FF30
20. DispatchInvoke: Got ref argument with type = 8 Value = 98765432109
21. DispatchInvoke: Params = 0145FF34
22. DispatchInvoke: Got ref argument with type = 8 Value = FISKAL 4
23. DispatchInvoke: MethodID: 1610743821 InvokeKind: 3
24. f9990122fd1b5fb0abe6bd43b54f94b6

And this is output when parameters are declared as String:

Code: Pascal  [Select][+][-]

1. ComObjDispatchInvoke called
2. ComObjDispatchInvoke: @CallDesc = $0044004C CallDesc^.ArgCount = 7
3. SearchIDs: Searching 1 IDs
4. SearchIDs: Original name: ZastitniKodIzracun Len: 18
5. SearchIDs: Translated name: ZastitniKodIzracun
6. SearchIDs: GetIDsOfNames result = 00000000
7. SearchIDs: ID[0] = 1610743821
8. DispatchInvoke: Got 7 arguments   NamedArgs = 0
9. DispatchInvoke: Params = 0145FF1C
10. DispatchInvoke: Got argument with type 8 Value = 100
11. DispatchInvoke: Params = 0145FF20
12. DispatchInvoke: Got argument with type 8 Value = 100
13. DispatchInvoke: Params = 0145FF24
14. DispatchInvoke: Got argument with type 8 Value = 100
15. DispatchInvoke: Params = 0145FF28
16. DispatchInvoke: Got argument with type 8 Value = 100
17. DispatchInvoke: Params = 0145FF2C
18. DispatchInvoke: Got argument with type 8 Value = ZastitniKodIzracun
19. DispatchInvoke: Params = 0145FF30
20. DispatchInvoke: Got argument with type 8 Value = FISKAL 4
21. DispatchInvoke: Params = 0145FF34
22. DispatchInvoke: Got argument with type 8 Value = FISKAL 4
23. DispatchInvoke: MethodID: 1610743821 InvokeKind: 3
24. 561d46a69e250b902276864552986b40

I couldn't find where "CallDesc" and "Params" are initially set, and I suspect the problem is there.
One more thing. At the beginning of the procedure ComObjDispatchInvoke 3rd parameter was still '19.11.2020 09:09:32', but after call to the SearchIDs procedure it was changed to 'ZastitniKodIzracun'.

I can give you needed dll's if you are willing to further debug this problem.

[PascalDragon]

Thanks for help. It is somewhat better but it isn't solved yet.

I enabled DEBUG_COMDISPATCH in ComObj.pas. This is test program I used:

Add {$mode objfpc}{$H+} at the top. By default FPC uses String = ShortString and those indeed don't work. (I've tested your code and I can reproduce your findings only with ShortStrings)

[dseligo]

You are right, that was the problem.

These are results with those compiler directives:

Code: Pascal  [Select][+][-]

1. ComObjDispatchInvoke called
2. ComObjDispatchInvoke: @CallDesc = $0044004C CallDesc^.ArgCount = 7
3. SearchIDs: Searching 1 IDs
4. SearchIDs: Original name: ZastitniKodIzracun Len: 18
5. SearchIDs: Translated name: ZastitniKodIzracun
6. SearchIDs: GetIDsOfNames result = 00000000
7. SearchIDs: ID[0] = 1610743821
8. DispatchInvoke: Got 7 arguments   NamedArgs = 0
9. DispatchInvoke: Params = 0145FF1C
10. Translating var ansistring argument 99.99
11. DispatchInvoke: Params = 0145FF20
12. Translating var ansistring argument 333
13. DispatchInvoke: Params = 0145FF24
14. Translating var ansistring argument P1
15. DispatchInvoke: Params = 0145FF28
16. Translating var ansistring argument 100
17. DispatchInvoke: Params = 0145FF2C
18. Translating var ansistring argument 19.11.2020 09:09:32
19. DispatchInvoke: Params = 0145FF30
20. Translating var ansistring argument 98765432109
21. DispatchInvoke: Params = 0145FF34
22. Translating var ansistring argument FISKAL 4
23. DispatchInvoke: MethodID: 1610743821 InvokeKind: 3
24. f9990122fd1b5fb0abe6bd43b54f94b6

[PascalDragon]

You are right, that was the problem.

Okay, then I'll make sure that the fixes I've done are merged to 3.2.1 so that they'll be in 3.2.2.