Hi list,

I'm sure I must be missing something.

I want to compile some grid drawing stuff depending on whether a grid bug has been fixed - i.e. I want to do something like this:

Had a look here:
http://wiki.lazarus.freepascal.org/IDE_Macros_in_paths_and_filenames ... but that only seems to specify support for FPC version, not Lazarus version.

Ideally, I'd be looking at something like:
  {$IF LAZARUSREVISION>=36180}
  // Note: normally, grid DefaultDrawing property must be off to avoid
duplicate drawing
  // This will result in duplicate drawing but should work.
  DefaultDrawing:=true;
  {$ENDIF}

Is something like this possible, or is there an easier way of doing things?

I realize that the code above will be compiled by FPC, not Lazarus; perhaps it is possible to set an environment variable LAZARUSREVISION and/or LAZARUSVERSION and get these into FPC macros in some way?

Thanks,
Reinier

I don't think so, in the general case. The Lazarus revision number can probably be found as a .inc in the ide directory, and post about 0.9.24 you can get the LCL version at runtime, but folding those back into something that could be used by a conditional will be problematic.

The revision is not possible (when using development versions you should try to use the latest revision), but for version you can use the unit LCLVersion. Just add it to the uses clause and then you can use e.g.:

{$if lcl_fullversion>=93100}
   // code that should work with 0.9.31 or newer
{$endif}

Just take a look at the unit to see which constants are supported (Note: it makes use of the feature that constants can be used in compiler conditionals)

Regards,
Sven

Op 22 maart 2012 11:50 heeft Mark Morgan Lloyd
het volgende geschreven:

I don't think so, in the general case. The Lazarus revision number can probably be found as a .inc in the ide directory, and post about 0.9.24 you can get the LCL version at runtime, but folding those back into something that could be used by a conditional will be problematic.

For examles using the version number, see:
http://lazarus-ccr.sourceforge.net/docs/lcl/lclversion/index.html and
http://svn.freepascal.org/svn/lazarus/trunk/examples/lclversion/

Vincent

Great, thanks, that works!

At that point if there's an ./ide/revision.inc file containing

// Created by Svn2RevisionInc
const RevisionStr = '35880M';

can it be included into a unit to make it visible at compile time?

And is there a way of getting $i to do something intelligent if the file it's looking for doesn't exist?

For the record, can you easily say what version of FPC introduced this capability?

According to a svn blame for the corresponding code this is in there at least since 2005 (when FPC switched from CVS to SVN and thus no older history is available to the public)

Regards,
Sven

Which probably makes it safe for 2.2.4, which corresponds approximately to 0.9.24.1 by which time the new-format lcl_fullversion etc. were available.

I was looking at these versions a few days ago, because I've got one project which I'm trying to keep compatible with GTK v1. Being to base coding decisions relating to e.g. Synedit capabilities on Lazarus rather than FPC version, without having to go to RTTI, is obviously a major advantage.

These constants were introduced EXACTLY for the purpose to use them in ifdefs. So yes, they are safe to use in this way ;)

Regards,
Sven

2012/3/22 Mark Morgan Lloyd :

You can add "$(LazarusDir)\ide" to the include paths of the project. Then this works:

{$I revision.inc}
const
  revIntroducedNewFeature = '55555';
begin
  {$IF (RevisionStr >= revIntroducedNewFeature)}
  UseNewFeature;
  {$ENDIF}
end;

True, although what I was really wondering was whether it could be pulled in purely by referencing a unit, rather than having $I all over the place. And there's still the issue of recovering gracefully if the include file isn't available or the version is non-numeric, i.e. has an appended M or reads "exported" because Lazarus wasn't built from SVN.

I've been having a bit of a play with this. Using the example above, am I correct in saying that this works

{$if lcl_fullversion>=93100}
   // code that should work with 0.9.31 or newer
{$endif}

but this doesn't

{$ifdef lcl_fullversion }
   // code that should work with any version that defines lcl_fullversion
{$endif}

As a variation of the latter, am I correct in saying that ifdef can't be used to check whether a function or procedure is implemented in some imported unit?

$ifdef does only work with defines (those done with -dXXX or {$define ...}), but not with identifiers/symbols (lcl_fullversion is a symbol). If you want to check for the existance of a symbol you need to use this:

{$if declared(lcl_fullversion) }
// code that should work with any version that defines lcl_fullversion
{$endif}
// Note: if you need Delphi compatibility you need to use {$ifend}
instead of {$endif} here

Regards,
Sven

Ah /ha/! So in other words I can use something like

{$if declared(SerGetRI) }
   WriteLn('Has SerGetRI');
{$endif }
{$if declared(SerGetCD) }
   WriteLn('Has SerGetCD');
{$endif }

to check whether the updated serial.pp that I attached to bug 18946 is actually available, rather than having to scratch around looking for it when I don't actually need to monitor CD.

Yes, that should work that way.

Regards,
Sven