How to know LCL version at compile time?

[theo]

How can I know against which LCL Version my source is compiled?

For example there is a change in GTKDef from 0.9.22 to 0.9.23 SVN:
From "ClipRegion: hRGN;" to "FClipRegion: PGdiObject;"

If I want my code to compile with the current stable version and the SVN version, I have to switch this.

Thanks

[Vincent Snijders]

As far as I know, you cannot know this.

[theo]

Thanks.
But it seems important in this case.
Should I place a feature request in the Bugtracker about this?
What do you think?

[Vincent Snijders]

I think it would be nice to have, but I don't see yet how this can be implemented.

Do you have an idea how this can be implemented?

[theo]

I'm not an expert but FPC does it with predefined Macros:

Table 2.1:    Predefined macros
   
Symbol    Contains
   
FPC_VERSION   The version number of the compiler.
FPC_RELEASE   The release number of the compiler.
FPC_PATCH    The patch number of the compiler.
   
You can then use them like:

{$if (fpc_version=0) and (fpc_release>6) and (fpc_patch>4)}  
{$info At least this is version 0.9.5}  
{$else}  
{$fatal Problem with version check}  
{$endif}


http://www.freepascal.org/docs-html/prog/progse5.html#x109-1090002.2
http://www.freepascal.org/docs-html/prog/progsu100.html#x114-1130002.4.2

[Vincent Snijders]

Yes, a compiler can do that. I don't think it is feasible to patch the compiler each time you change lazarus version.

An option could be that lazarus passes -dLCL_0_9_23 to the compiler if the lazarus version in 0.9.23. I don't know if it is possible to pass constants like lcl_version=0 and lcl_minor=9 to the compiler.

[theo]

Don't know if this is intelligent, but we could put this code in a lazver.inc file in the lcl dir:

  {$MACRO ON}
  {$Define lcl_version:=0}
  {$Define lcl_minor:=9}
  {$Define lcl_patch:=23}    

Then applications which need to know can include this file and use the info like:

{$ifdef lcl_version} {$ifdef lcl_minor} {$ifdef lcl_patch}
   {$if (lcl_version>=0) and (lcl_minor>=9) and (lcl_patch>=23)}
     Caption:='This is a version >= 0.9.23' ;
   {$endif}
  {$endif} {$endif}{$endif}
{$MACRO OFF}

Maybe not so clever for backward compatibility, when the lazver.inc file isn't there.
Maybe in combination with: -dHAVE_LCL_VER_FILE:

  {$IFDEF HAVE_LCL_VER_FILE}
    {$I lazver.inc}
  {$ENDIF}  

But you certainly know a better solution ;-)

[Marc]

I see no need for is. As long as the lcl is not 1.0 interfaces might change. After that is should stay the same.

[Vincent Snijders]

Because it changes, component developers need to know what version they compile against.

I think we need this feature. Theo, can you create a bug report. I will look into it.

[theo]

OK, done:

http://www.freepascal.org/mantis/view.php?id=10250

[Marc]

either way (i' still not convinced), you don't need defines, putting it constants works too (and can evenbe used in code when needed)

[theo]

It's just an idea.
How would you do that with constants?