[CMake] How to query compiler definitions?

[Michael Wild]

On 01/19/2011 03:45 PM, SF Markus Elfring wrote:
>> set_source_files_properties(debug_funcs.c PROPERTIES
>>    EXCLUDE_FROM_CONFIGURATIONS "Release;MinSizeRel")
> 
> I do not want to exclude this file based on the value of the variable
> "CMAKE_BUILD_TYPE".   ;-)

Why not? That's mostly equivalent to doing it based on -DNDEBUG (which
is automatically defined for Release and MinSizeRel). Or is it actually
another criterion (such as whether testing is enabled)?

> 
> 
>> I don't think it would make to do this based on preprocessor definitions.
> 
> It seems that our ideas converge.   :-)
> 
> 
>> So, toy.cxx is not actually the problem,
> 
> Correct.
> 
> 
>> but you don't want to link against the XML library.
> 
> Partly. yes.
> 
> I am affected by a general issue from C++ class libraries. The
> corresponding free source files were copied to a subdirectory of the
> project I am interested in because a public shared library (*.so/*.dll)
> seems to be missing for it. (The project has got its own bundle of
> external software.)
> 
> Library features are used in a limited way so far. This has got the
> consequence that its compilation should be optional for specific
> application parts.
> 
> 
>> Do you need the library anyways (e.g. for other targets) [...] ?
> 
> The software test part depends on the C++ class library unconditionally.

So, you always build tinyxml? In that case, simply use this:

------------<8------------

add_library(tinyxml STATIC
  tinyxml/tinystr.cpp
  tinyxml/tinyxml.cpp
  tinyxml/tinyxmlerror.cpp
  tinyxml/tinyxmlparser.cpp)

------------<8------------

add_executable(super a.cpp b.cpp c.cpp toy.cpp)
target_link_libraries(super debug tinyxml)

In that case, super will be linked against the tinyxml target only for
the debugging configurations.

> 
> 
>> However, if libxml is required for debugging only and you don't want to
>> require it unconditionally, you have a problem and I can't see an easy
>> way around it.
> 
> The utility "http://grinninglizard.com/tinyxml/index.html" is needed in
> my case.
> 
> Regards,
> Markus

Michael