Compiler definiton for lcl like {$IF LCL_VERSION>2} ?

[jwdietrich]

I have now thoroughly checked this issue again with Lazarus versions 1.2.6, 1.6.2, 1.8.4 and 2.0.2 on Linux, macOS and Windows.

If I use the LCL_FullVersion conditional (or some of its equivalents like LCL_MAJOR) in the implementation part everything works well. However, using it in the interface part raises the error as described. See a short example in the next section or in the attached file with a demo project. This project can only be compiled after commenting out lines 10 to 12 of unit1.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   ExtCtrls, LCLVersion
10.   {$IF LCL_MAJOR >= 2}           // <- This doesn't work
11.     , LazVersion
12.   {$ENDIF}
13.   ;
14.  
15. ...
16.  
17. implementation
18.  
19. ...
20.  
21. procedure TForm1.FormCreate(Sender: TObject);
22. begin
23.   {$IF LCL_MAJOR >= 2}              // <- This works
24.     RadioGroup1.ItemIndex := 2;
25.   {$ELSE}
26.     {$IF LCL_MAJOR >= 1}
27.       RadioGroup1.ItemIndex := 1;
28.     {$ELSE}
29.       RadioGroup1.ItemIndex := 0;
30.     {$ENDIF}
31.   {$ENDIF}
32. end;
33.  
34. end.

This is a pity, since conditionals are much more needed at compile time than at runtime.

[Zoran]

Ah, I see now what you are trying to do.
You are trying to use the constant before uses section ended.
No, you can't do that.

However, you can use it in interface section, but parser needs to finish the uses block before it can see the constants.

This compiles well:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs,
9.   LCLVersion
10.   ;
11.  
12. {$if lcl_major >= 2}
13. type
14.   TSomething = Integer;
15. {$endif}
16.  
17. type
18.   TForm1 = class(TForm)
19.   private
20.  
21.   public
22.  
23.   end;
24.  
25. var
26.   Form1: TForm1;
27.  
28. implementation
29.  
30. {$R *.lfm}
31.  
32. end.
33.  

[wp]

Or, if possible, put the conditionally excluded unit into the uses clause of the implementation section. This works for me:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   ExtCtrls, LCLVersion;
10.  
11. ...
12.  
13. implementation
14.  
15. {$IF LCL_MAJOR >= 2}
16. uses
17.   LazVersion;
18. {$ENDIF}
19.  
20. ...
21.  

[jwdietrich]

Thanks, @Zoran and @wp. It works now. At least for me, a major issue that thwarted the evolution of one of my major projects is solved.