[CMake] Problems with Qt MOC and conditional compilation.

[Filipe Sousa]

Tim Sutton wrote:
> Hi all
> 
> Can someone help me with getting conditionally #defined code blog to
> compile using cmake?
> My CmakeLists.txt file has: ADD_DEFINITIONS(-DWITH_QGIS) and I have
> some code blocks in .h and .cpp that conditionally compile based on
> this e.g.
> 
> #ifdef WITH_QGIS
>     foo...
> #endif
> 
> The problem I have is that only the ifdefs in the .cpp are properly
> being entered into & compiled, while in the .h the code is skipped. My
> theory is this is because the -DWITH_QGIS is not being passed along to
> MOC when it is run on the header file.
> 
>  87 #ifdef WITH_QGIS
>  88       void zoomInMode();
>  89       void zoomOutMode();
>            etc...
>  99 #endif
> 
> If I comment out the ifdef, MOC runs and my Qt slots work properly.
> Has anyone encountered a similar issue? I am using cmake version
> 2.4-patch 5 on ubuntu feisty. When compiled with qmake the same code
> works fine so I am thinking this is coming back to the way that cmake
> is calling moc?
> 
> Many thanks!

I've been looking into to the code and the preprocessor definitions is 
missing

Add this code after QT4_GET_MOC_INC_DIRS(moc_includes) to the macro 
QT4_WRAP_CPP (FinfQt4.cmake) and see if it works:

GET_DIRECTORY_PROPERTY(_flags DEFINITIONS)
SEPARATE_ARGUMENTS(_flags)
LIST(APPEND moc_includes ${_flags})

I didn't test
--
Filipe Sousa