On 24.03.2012 19:35, Mark Morgan Lloyd wrote:
Sven Barth wrote:
Am 22.03.2012 14:10, schrieb Mark Morgan Lloyd:
Sven Barth wrote:
Am 22.03.2012 13:28, schrieb Mark Morgan Lloyd:
Sven Barth wrote:
Am 22.03.2012 11:32, schrieb Reinier Olislagers:
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?
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}
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)
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.
These constants were introduced EXACTLY for the purpose to use them in
ifdefs. So yes, they are safe to use in this way ;)
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
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